Analytica doi: 10.3390/analytica7020032

Authors: Vladimir V. Poborchii Dmitrij Rappoport

We studied experimentally and computationally the structures and optical properties of sulfur (S), selenium (Se) and tellurium (Te) ring clusters. We encapsulated S, Se and Te into AFI, MOR, CHA and LTA zeolites via vapor adsorption or high-pressure injection from melt and studied Raman and optical absorption spectra (RS and OAS, respectively) of zeolite single crystals with incorporated S, Se and Te ring clusters. Importantly, strict orientation of the rings in zeolite crystals allowed us to study the polarization/orientation dependency of ring RS and OAS. The obtained experimental spectra are found to be in agreement with density functional theory results (DFT using the PBE0 functional and def2-TZVP basis sets) for S8, Se6, Se8, Se12, Te6 and Te8 ring molecules. The agreement is especially good for Te rings, while for S and Se rings harmonic frequency scaling factors are required. The S and Se rings display light-induced effects, which we attribute to the presence of conical intersections between their ground and excited electronic states, resulting in isomerization and subsequent fragmentation. We consider this effect using the Se6 ring example. This phenomenon is important for understanding photostructural changes not only in chalcogen clusters but also in bulk materials such as amorphous selenium.

Analytica doi: 10.3390/analytica7020031

Authors: Virginia G. Correia Victor F. Jesus Rodolfo S. Barboza Alviclér Magalhães Leonardo N. Seito Mário Gomes Marcelo R. R. Tappin Ligia M. M. Valente

The species Psychotria densicostata Müll.Arg. is a shrub belonging to the Rubiaceae family, endemic to Brazil. So far, there are reports neither of phytochemical work on nor of biological evaluation of it. This study investigated its alkaloid profile and evaluated the inhibitory effects of extracts, alkaloid-enriched fractions and one of its major constituents on human neutrophil elastase (HNE). The monoterpene indole alkaloids (MIAs) strictosidine (1), (3α,5α)-5-carboxystrictosidine (2), strictosidine lactam (3), lyaloside (4), lyalosidic acid (5), 5-carboxystrictosamide (6), 3,4-dehydrostrictosidinic acid (7), and N-glucopyranosyl vincosamide (8) were characterized in mixture, in its leaves, and/or stems by using an integrated approach combining nuclear magnetic resonance (NMR) techniques, high performance liquid chromatography coupled to a tandem mass spectrometer with an electrospray ionization source (HPLC-ESI-MS/MS), and molecular networks. The crude leaf extract and an alkaloid-enriched fraction derived from it showed inhibitory activity against HNE. These results contribute to the chemical knowledge of the species and suggest its potential biological property.

Analytica doi: 10.3390/analytica7020030

Authors: Stela Jokić Ema Pavičić Valentina Masala Carlo Ignazio Giovanni Tuberoso Snježana Keleković Drago Šubarić Martin Lalić Krunoslav Aladić

The herbal tea industry has experienced substantial growth, particularly regarding green tea (Camellia sinensis). In the manufacturing of filter tea, fine herbal dust is generated as a residual by-product during grinding and sieving and is typically discarded as waste. This study aims to explore the application of ultrasound-assisted extraction (UAE) for secondary valorisation of green tea herbal dust by investigating the effects of various parameters on extraction efficiency. Antiradical activity of UAE extracts was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the total phenolic content (TPC) was measured using Folin–Ciocalteu’s assay. Furthermore, selected phenolics were quantified by HPLC and qualitatively characterised by liquid chromatography coupled with electrospray ionisation and quadrupole time-of-flight tandem mass spectrometry (LC-ESI-QToF-MS/MS). The results demonstrate that UAE parameters have a pronounced influence on the antioxidant activity, TPC, and individual polyphenolic profile of green tea herbal dust extracts. Ethanol–water mixtures at a ratio of around 40–60%, as well as moderate impulse regimes (around 60%) and extraction times (around 10 min), were the most suitable for extracting green tea polyphenols. Epigallocatechin gallate was the predominant phenolic component in most extracts, alongside epicatechin, epigallocatechin, catechin, and gallic acid. The findings highlight the UAE technique as a robust, green, and scalable method for valorising green tea by-products, thereby facilitating the development of high-value natural extracts for applications in the food, pharmaceutical, and cosmetic industries.

Analytica doi: 10.3390/analytica7020029

Authors: Sebastian Scharf Lara Preuß Peter Winterhalter Recep Gök

C13-Norisoprenoids are important contributors to the aroma of Riesling wine. Their quantification is analytically challenging due to their low concentrations, the lack of commercial standards and their pronounced sensitivity to analytical conditions, reflecting their chemical lability, as well as the dynamic nature of the wine matrix, leading to high reactivity and, consequently, remarkable structural diversity. Here, we developed an assay for the analysis of C13-norisoprenoids in wine using headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry (HS-SPME–GC-MS/MS). After evaluating different fiber materials, a statistical design of experiments (DoE) approach was employed to systematically optimize key HS-SPME parameters, including incubation, extraction and desorption conditions. Selected reaction monitoring (SRM) transitions were established for all targeted C13-norisoprenoids, allowing the assay to provide relative quantification of more than 40 compounds using representative labeled and unlabeled standards to generate linear calibration curves. Following method validation, this approach was applied to a young German Riesling wine to investigate the effect of various acidic hydrolysis conditions on the norisoprenoid profile as well as on specific compounds. A central composite design (CCD) was used to systematically study the impact of pH, temperature, and hydrolysis time. Quantitative data were obtained for 22 C13-norisoprenoids demonstrating that hydrolysis conditions strongly affected the norisoprenoid composition. pH and temperature showed a greater influence than reaction time. Response surface models (RSM) indicated that TDN, Vitispirane and TPB in particular are predominantly formed under strongly acidic and high-temperature conditions, whereas others such as Riesling acetal and actinidols are formed under milder conditions. The results indicate that hydrolysis conditions should be tailored to the specific norisoprenoid under investigation and the research question, particularly when simulating conditions of accelerated wine ageing for analytical purposes.

Analytica doi: 10.3390/analytica7020028

Authors: Isabella C. S. Nascimento Andressa M. Souza Andrea P. Parente Edna M. M. Oliveira Andrea Valdman Rossana O. M. Folly Andrea M. Salgado

A quartz crystal microbalance-based biosensor for the specific detection of the first transgenic common bean (L.) cultivar (BRS FC401 RMD) with resistance to Bean golden mosaic virus (BGMV) was developed. The immobilization chemistry relies on the strong bond between the thiolated probe and the gold electrode surface. The probe sequence is internal to a region of the BGMV rep gene that was introduced into the common bean genome. The sensor’s analytical performance was determined using synthetic oligonucleotides. Real samples of transgenic and wild-type bean seeds were also tested. Sample pretreatment consisted only of enzymatic fragmentation, followed by a thermal denaturation step combined with blocking oligonucleotides. Different biosensor regeneration approaches were studied. Immobilization showed good reproducibility (CV% of 5.8%). The biosensor proved specific for both synthetic oligonucleotides and non-amplified genomic DNA. A linear detection range of 0–1.4 ng/µL was observed, with a detection limit of 0.18 ng/µL. Three sequential detections were performed without loss of surface activity. The results demonstrate the biosensor’s potential for direct, real-time, label-free detection of DNA samples for field screening of transgenic common bean cultivars.

Analytica doi: 10.3390/analytica7020027

Authors: Diego García-Gómez Ana Ballester-Caudet María Esther Fernández Laespada

Secondary electrospray ionization mass spectrometry (SESI-MS) has emerged as a powerful technique for the real-time, non-invasive analysis of volatile organic compounds (VOCs) in complex matrices, such as exhaled breath and microbial volatilomes. However, its transition to routine application is hindered by significant challenges in absolute quantification, unambiguous identification, and standardization. This review provides a comprehensive overview of these limitations and the emerging solutions proposed to overcome them. Matrix effects, including gas-phase ion suppression and C-trap competition, are examined alongside mitigation strategies such as spectral stitching and standard addition. To enhance quantification stability, advanced standard delivery systems and dynamic quality control protocols are evaluated. The identification bottleneck—stemming from the absence of chromatographic separation—is addressed through the use of curated databases and advanced fragmentation techniques, such as incremental quadrupole acquisition to resolve overlapping spectra (IQAROS), to resolve isobaric interferences. Furthermore, the role of chemometrics in extracting biological fingerprints is discussed. Finally, the need for harmonized reporting standards and multicenter validation is emphasized to ensure cross-study reproducibility. Resolving these methodological gaps is essential for the clinical and industrial translation of SESI-MS.

Analytica doi: 10.3390/analytica7020026

Authors: Andrey Shishov Ekaterina Davydova Yaroslava Chepasova Nikita Tsvetov Alexey Savko Ilya B. Zavodnik

Natural deep eutectic solvents (NADES) offer sustainable alternatives to conventional solvents for plant extraction, yet their influence on extract composition and bioactivity preservation requires further study. Here, choline chloride-based NADES with lactic acid or propylene glycol were evaluated for ultrasound-assisted extraction (60 °C, 30 min, 1:20 w/v) of polyphenol-rich fractions from Sanguisorba officinalis and Symphytum officinale. Spectrophotometric analysis yielded total phenolic contents of 6.49–9.67 mg GAE g−1 and total flavonoids of 0.08–0.52 mg g−1, with values dependent on the plant matrix and the NADES formulation. Targeted HPLC-MS/MS enabled identification of representative phenolic acids (chlorogenic, caffeic, ferulic, rosmarinic) and flavonoid markers (rutin, quercetin derivatives), showing qualitative differences in the detected marker profiles between solvents and matrices. Functional assays demonstrated pronounced antioxidant-related effects, including DPPH radical scavenging at 0.5–25 µg mL−1 (polyphenols), inhibition of lipid peroxidation in rat erythrocytes at 0.25–1.20 µg mL−1, and modulation of mitochondrial respiration and permeability transition in isolated rat liver mitochondria. Overall, the results indicate that choline chloride-based NADES can be used to obtain polyphenol-rich plant extracts compatible with the applied analytical workflow while preserving redox-active fractions, supporting their utility in green analytical sample preparation.

Analytica doi: 10.3390/analytica7010025

Authors: Yiling Liu Jinjuan Xue Fan Xia Jia Chen Jianfeng Wu Shuxuan Cao Wei You Jinqiao Jiang Xiaolei Zhang Jianwei Xie

Phosphonyl tyrosine is one of the main biomarkers to confirm exposure to highly lethal organophosphorus nerve agents (OPNAs) in vivo. However, a critical challenge remains unresolved: ionization suppression occurs during the analysis of phosphonyl tyrosine by high-resolution mass spectrometry (HRMS) or tandem mass spectrometry (MS/MS), which is induced by the high concentrations of free amino acids present in the digestion solution. In this study, based on the broad-spectrum immunomagnetic beads with high affinity antibodies, a non-targeted early warning and verification strategy was developed. Compared with the recommended operating procedures for analysis in the verification of chemical disarmament, the total analysis time was reduced from several hours to about 30 min. Moreover, the detection sensitivity was increased by nearly one order of magnitude, and the detection limit (LOD) was 0.01 ng/mL. Furthermore, the screening strategy can cover all OPNAs listed as 1A.01, 1A.02 and 1A.03 in Schedule 1 of the CWC. Therefore, we have developed a rapid, sensitive, and broad-spectrum approach to accurately screen for OPNAs exposure, while also offering a novel strategy and technical support for chemical defense and occupational health assessment.

Analytica doi: 10.3390/analytica7010024

Authors: Milena Rmandić Marija Rašević Kostas Gkountanas Ana Protić Anđelija Malenović Yannis Dotsikas

Impurity profiling is of significant analytical and regulatory importance, particularly in the context of lifecycle quality management. A robust chaotropic chromatography method was developed for the determination of olanzapine and its two oxidative degradation products in tablets, in accordance with the ICH Q14 guideline and the principles of Analytical Quality by Design (AQbD). Risk assessment was performed using a combination of the Ishikawa diagram, CNX (Control, Noise and eXperimental) classification, and Failure Mode and Effect Analysis (FMEA). This multistep evaluation identified the critical analytical procedure parameters (APPs) as the acetonitrile content in the mobile phase, the concentration of perchloric acid in the aqueous phase, and the pH of the aqueous phase. These APPs were studied using an experimental design approach to model their effects on key analytical procedure attributes and to compute a multidimensional design space. Robust optimization supported by Monte Carlo simulations ensured compliance with predefined acceptance criteria with a probability of at least 95%. Method validation demonstrated adequate selectivity, limits of quantification of 0.75 µg/mL and 0.5 µg/mL for impurities B and D, linearity with correlation coefficients ≥0.990, accuracy of 98–102% for olanzapine and 70–130% for impurities, and repeatability with RSD ≤2% for the assay and ≤10% for impurities. The method was successfully applied to commercial tablet analysis.

Analytica doi: 10.3390/analytica7010023

Authors: Renata Karpicz Viktorija Rapalyte Danielis Rutkauskas

Light-sensitive protecting chemical groups play an important role in the control of chemical reactions with high spatial and temporal resolution. Various forms of o-nitrobenzyl as a protecting compound are used for light-directed DNA synthesis. The suitability of a particular derivative for the application is defined by its photolytic efficiency, a characteristic, that is commonly extracted from a repetitive HPLC procedure. Here, using an example of a phosphoramidite compound with improved properties of deprotection, we delineate a simplified and economic approach based on a measurement of absorbance spectra to evaluate the photolytic efficiency. The obtained values are in close agreement with those determined previously.

Analytica doi: 10.3390/analytica7010022

Authors: Mina Kim Sang Yun Han

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a powerful technique for polymer identification because it can ionize intact macromolecules with large molecular weights (>100 kDa) and detect them over a theoretically unlimited mass range. However, limited mass resolution, accuracy, and sensitivity in the high-mass region restrict detailed structural characterization of polymers. Depolymerization into smaller fragments using established chemistry, such as transesterification, provides a versatile alternative approach. The resulting characteristic fragments (<3 kDa) are polymer-specific and enable both polymer identification and detailed structural analysis, benefiting from the higher mass accuracy and sensitivity in the low-mass range and allowing MS/MS-based identification. To establish general sample-preparation conditions, this study systematically investigated the effects of transesterification of biodegradable polyesters using MeO−/MeOH, EtO−/EtOH, and t-BuO−/t-BuOH on subsequent MALDI-TOF MS analysis. Among the reagents examined, EtO−/EtOH combined with THAP/THF matrix treatment was found to be the most efficient, enabling rapid polyester analysis by MALDI-TOF MS within 10 min when the reaction time and reagent concentration were carefully controlled within an optimal window.

Analytica doi: 10.3390/analytica7010021

Authors: Atikah Mohd Nasir Nur Hanis Najihah Mohd Kamal Noor Hazfalinda Hamzah

The forensic reliability of biological fluids in sexual assault investigations depends on substrate type, environmental exposure, time since deposition, and analytical methodology. This systematic review evaluates the forensic reliability of major biological fluids, semen, blood, saliva, and vaginal secretions by comparing detectability and persistence on porous and non-porous substrates, assessing environmental and temporal effects on DNA integrity, and examining the performance of identification methods. A systematic search of PubMed, Scopus, and Web of Science (2001–2025) was conducted following PRISMA 2020 guidelines. Eligible studies investigated fluid persistence, degradation, or identification reliability under controlled or casework-relevant conditions. A weighted scoring framework categorised relative reliability. Twenty-seven studies met inclusion criteria. Semen and blood demonstrated higher reliability across substrates, particularly when collected within recommended timeframes. Porous substrates reduced surface detectability but occasionally preserved DNA from rapid degradation. Elevated temperature, humidity, and prolonged intervals consistently reduced DNA quality and detection success. Molecular approaches, including mRNA profiling, showed enhanced specificity in degraded or mixed samples, though methodological variability limited direct comparability across studies. The forensic reliability of biological fluids is context-dependent, shaped by complex interactions between substrate characteristics, environmental exposure, and analytical technique. Semen and blood remain robust DNA sources, while emerging technologies offer improved specificity in challenging scenarios. Standardised evaluation frameworks and timely evidence collection remain essential to enhance evidential value and minimise misinterpretation in sexual assault investigations.

Analytica doi: 10.3390/analytica7010020

Authors: Samuel King Brock Wright Cenk Suphioglu

Objectives: Using high-performance liquid chromatography (HPLC), we developed and validated an in vitro assay for the quantitative determination of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) activity, supplementing limited current methodologies to assess the efficacy of BACE1 inhibitor compounds. A hexa-histidine tagged peptide substrate of BACE1 was used as the analyte for the determination of in vitro BACE1 activity; it was validated according to ICH guidelines. Methods: The HPLC analysis was performed on the Agilent 1290 Series Infinity II UHPLC System equipped with a Phenomenex Kinetex EVO C18 (100 × 3 mm) 5 µm column. The method was developed using a gradient programme comprising 10% aqueous acetonitrile (0.02 M TFA) to 30% aqueous acetonitrile (0.02 M TFA) for 5 min at a flow rate of 0.6 mL/min. Results: The method showed linearity over the range of 14.92 to 72 µM with r2=0.9997. The accuracy of the method in terms of mean recovery ranged between 96.62 and 98.38%. The %RSD for intra- and inter-day precision was less than 5%. Two commercial inhibitors, AZD3839 and OM99-2, were used to evaluate the performance of the method at their respective IC50, resulting in inhibition of 53.46 and 50.74%, respectively. The described method addresses the void for a practical and cheap alternative to quantitatively determine the activity of BACE1 compared to current commercially available detection assays. Conclusions: We have successfully developed an HPLC method to measure the inhibitory function of two commercial inhibitors of BACE1, indicating the suitability of the method for the identification and characterisation of novel BACE1 inhibitors.

Analytica doi: 10.3390/analytica7010019

Authors: Fotouh R. Mansour Marcello Locatelli Reem H. Obaydo Amir Shaaban Farag Alaa Bedair

White Analytical Chemistry (WAC) provides a holistic framework for evaluating analytical methods by balancing analytical performance, environmental sustainability, and practical efficiency. Existing WAC assessment tools offer structured evaluation but often lack flexibility or comprehensiveness. To bridge this gap, we introduce the Whiteness Evaluation for Chemical Analysis (WECA) tool as a dynamic, web-based application that enables customizable, context-aware assessment of analytical methods. WECA allows users to select 2–4 criteria per RGB domain (Red: analytical performance; Green: environmental impact; Blue: practical efficiency), assign user-defined weights, and visualize results through an intuitive color-coded interface. The tool calculates a composite WECA score (%) that reflects overall method “whiteness”. Three case studies, covering HPLC-DAD, micellar electrokinetic chromatography, and electrochemical sensing, demonstrate WECA’s applicability and its ability to highlight method strengths and weaknesses across diverse analytical scenarios. WECA represents a step toward more adaptable, transparent, and visually intuitive method evaluation in alignment with the evolving principles of WAC.

Analytica doi: 10.3390/analytica7010018

Authors: Camila Bardy Luis Manuel Menéndez-Quintanal Gemma Montalvo Carmen García-Ruiz Begoña Bravo Serrano Jose Manuel Matey

High-resolution mass spectrometry (HRMS) enables non-targeted detection of drugs and metabolites in complex matrices. Phase II metabolites—especially glucuronides—are often the only detectable biomarkers in late or postmortem samples but are underrepresented in commercial libraries. This work pursued the prediction of phase II-glucuronide conjugates in diluted urine samples by non-targeted/targeted LC-HRMS workflows. A simply “dilute-and-shoot” qualitative UHPLC-HRMS/MS method (Q Exactive HF, ddMS2) was integrated with Compound Discoverer® software for data processing. The workflow incorporated predictive strategies such as exact mass suspect lists, Structured Query Language (SQL)-based filters, compound-class and diagnostic neutral-loss rules (including the characteristic loss of 176.0321 Da for glucuronides) and MS/MS confirmation using both in-house and public spectral libraries. An additional part of the application’s performance assessment involved its validation for diluted urine sample. A qualitative validated method for more than two hundred drugs in urine samples was performed, including the method’s selectivity/specificity, limit of identification, matrix effects, and potential carryover. Most analytes fulfilled the qualitative acceptance criteria, with more than 60% successfully identified at a concentration of at least 2.5 ng/mL. Matrix effects were within acceptable limits for most compounds, and no severe ion suppression was observed. A non-targeted workflow was applied to real forensic samples (n = 16), allowing a reduction of approximately 66,800 detected features to 225 glucuronide candidates, while a targeted workflow based on exact mass lists yielded 31 high-confidence identifications. Characteristic neutral losses and diagnostic fragment ions led to the tentative identification of some glucuronide phase II metabolites such as mirtazapine–glucuronide, morphine-6–glucuronide, and glucuronide conjugates of benzodiazepines and synthetic opioids. In conclusion, the integration of biotransformation knowledge with HRMS-based predictive filtering allows for the efficient and hydrolysis-free detection of glucuronide metabolites, thereby extending detection windows and enhancing toxicological interpretation in complex forensic scenarios. This adaptable and library-independent workflow also facilitates retrospective data mining, making it suitable for the identification of emerging substances and newly characterized metabolites.

Analytica doi: 10.3390/analytica7010017

Authors: Nurcan Dedeoğlu Seçil Karahüseyin

Taraxacum mirabile Wagenitz, one of the endemic riches of Anatolia, is a species that has remained largely unexplored regarding its enzyme inhibition profile despite its pharmacological potential. The effects of T. mirabile aerial and root extracts, obtained at different polarities, were scrutinized in this study against two important enzymes: lactoperoxidase (LPO), which plays a vital role in the innate immune system, and xanthine oxidase (XO), which is prominently associated with hyperuricemia and oxidative stress. The aerial and root portions of the plant were extracted into fractions of varying polarities using petroleum ether, dichloromethane, ethyl acetate, and butanol. LPO was isolated from buffalo milk (881.6-fold purification, 22.5% yield, and 1249.9 EU/mg specific activity) via affinity chromatography and used in in vitro inhibition assays alongside commercial bovine XO enzyme. The results showed that the ethyl acetate fraction of the aerial part of the plant exhibited the strongest LPO inhibition (IC50: 15.60 ± 0.77 µg/mL) among the fractions. The petroleum ether fraction of both the aerial part (IC50: 11.17 ± 0.94 µg/mL) and the root part (IC50: 11.61 ± 0.59 µg/mL) had the highest inhibitory effect for the XO enzyme. These distinct inhibition profiles allow for significant insights into how plant extracts with varying polarities modulate XO and LPO enzymes. In conclusion, the significant inhibitory activity of T. mirabile extracts toward LPO and XO enzymes highlights their potential as a natural source for developing effective enzyme inhibitors, which could be useful for therapeutic applications.

Analytica doi: 10.3390/analytica7010016

Authors: Paolo Inaudi Gabriele Ruggieri Elena Orrù Ornella Abollino Agnese Giacomino Letizia Mazzoni Mery Malandrino Francesca Durbiano

A simple mechanical polishing treatment of commercial solid-gold electrodes (SGEs) can renew the active gold surface, reduce manufacturing-related grooves, and markedly improve the repeatability of geometric-area estimation and the analytical performance in stripping voltammetry. The work focuses on the accurate determination of the geometric area of a SGE by two voltammetric techniques. Cyclic voltammetry (CV) at different scan rates, referred to as the Randles–Ševčik equation, and voltage scans at different electrode rotation rates, based on the Levich equation, were performed. The geometric area of the SGE was also evaluated by scanning electron microscopy (SEM). Commercial SGEs show grooves on their surface, derived from the fabrication processes. The effects of these grooves on the voltammetric response were investigated. The measurements were carried out on the SGE both as received from the manufacturer and after a reduction in the grooves height by a drastic mechanical treatment. After the treatment, the estimated area values were lower and more precise (3.05 ± 0.02 mm2). Moreover, the reduction in the grooves’ height affected the area estimations in contrast with the meaning of the geometric area, as intended by the Randles–Ševčik and Levich equations. Furthermore, the gold exposed surface was measured by CV in sulphuric acid. Finally, the SGE was tested for the detection of Hg in a NaCl solution by anodic stripping voltammetry: the repeatability of the response improved after the mechanical treatment, confirming the usefulness of this step before electrode usage.

Analytica doi: 10.3390/analytica7010015

Authors: Alissa Jonas Ian Gering Elena Schartmann Sarah Schemmert Dieter Willbold Beatrix Santiago-Schübel Janine Kutzsche

The all-d-enantiomeric-peptide RD2 was developed for the treatment of Alzheimer’s disease. This study aimed to develop a specific and highly sensitive liquid chromatography-mass-spectrometric (UHPLC-ESI-QTOF) method for quantifying RD2 in the mouse brain and to validate it according to the ICH M10 guideline to investigate the pharmacokinetic profile of RD2 in its target organ. Sample preparation, chromatographic separation and quantification were very challenging due to RD2’s highly hydrophilic properties, the complex matrix and the required lower limit of quantification (LLOQ). Chromatographic separation was performed on an Acquity UPLC BEH C18 column (2.1 × 100 mm, 1.7 μm particle size) within 5 min at 50 °C with a flow rate of 0.5 mL·min−1. Mobile phases consisted of water and acetonitrile with 0.2% formic acid and 0.015% heptafluorobutyric acid. Ions were generated by electrospray ionization in the positive mode, and RD2 was quantified by QTOF-MS. The developed extraction method revealed complete recovery. The linearity of the calibration curve was in the range of 2 ng·mL−1 to 500 ng·mL−1 (R2 > 0.99) with a LLOQ of 5 ng·mL−1. The intraday and interday accuracy and precision ranged from 0.4% to 12.2% and from 1.0% to 12.0%. RD2 remained stable in the freshly homogenized brain even after several freeze–thaw cycles, but stability decreased over time during long-term storage at −80 °C. Using this validated method, RD2-spiked brain homogenate samples and samples of a pharmacokinetic study with RD2 in mice were analyzed.

Analytica doi: 10.3390/analytica7010014

Authors: Zine Eddine Hamoum Hervé Carrier Brice Bouyssiere Marie Larregieu Pierre Chiquet Isabelle Le Hécho

In the context of the energy transition and the increasing deployment of low-carbon gases (hydrogen, biomethane), reliable analytical monitoring is required to support integrity assessment and traceability of gas infrastructures under diverse on-site conditions while limiting analytical costs through standardized sampling and a single analytical system. We developed and validated integrated workflows combining sampling and laboratory analysis for chemical and compound-specific isotope analysis (CSIA) of natural gas and associated gaseous effluents in underground storage. An original quantification approach was implemented, linking sampling pressure to the amount of each compound collected in vials, and coupled with δ13C and δ2H measurements of alkanes (C1–C3), CO2 and H2. Two complementary sampling modes were optimized and compared: conventional high-pressure cylinders and direct collection into vacuum-sealed vials suitable for a broad range of pressures and field conditions. Using reference gas mixtures and operational samples, both approaches showed good reproducibility and isotopic accuracy during laboratory validation and over two years of monitoring. In particular, δ2H determinations for alkanes and H2 remained robust under low-pressure sampling typical of annular spaces (~1–2 bar), despite gas-composition fluctuations. These validated methodologies provide a flexible basis for routine, standardized monitoring of stored and circulating gases, including emerging low-carbon components.

Analytica doi: 10.3390/analytica7010013

Authors: Emiliane Daher José Emeri Helvecio Vinicius Antunes Rocha Livia Deris Prado José Carlos Pinto

The primary objective of the current study is to establish and validate for the first time a method to determine and quantify praziquantel (PZQ) and its main degradation products loaded in poly(methyl methacrylate–co-2-(diethylamino)ethyl methacrylate) P(MMA-co-DEAEMA) microparticles. A high-performance liquid chromatography (HPLC) approach was developed and validated in accordance with the United States Pharmacopeia (USP) guidelines, addressing parameters such as accuracy, linearity, solution stability, precision, specificity, robustness, sensitivity, and system suitability. The method employed a gradient mobile phase consisting of ultrapure water and acetonitrile, flowing at a rate of 1 mL/minute over a Phenomenex Kinetex® C18 column (5 µm, 100 Å, 250 × 4.6 mm) maintained at 35 °C. Detection was performed at the wavelength of 210 nm using a DAD/UV detector. Samples of the active pharmaceutical ingredient (API) praziquantel, microencapsulated praziquantel, placebo, and a mixture of related substances (A, B, and C) were prepared with 0.5% formic acid in water/ethanol, 45:55 v/v as the diluent, and injected at 20 °C. The method demonstrated a limit of quantification (LOQ) of 0.20 µg/mL for praziquantel and related substances. The method exhibited an excellent linear response, with all correlation coefficients (R2) values exceeding 0.998, which is well above the recommended specified limit of R2 > 0.995. Percent recoveries fell within the acceptable range of (95.0–105.0%), and all results indicated a percentage of relative standard deviation (%RSD) ≤ 2.0, indicating a robust methodology. Thus, the proposed HPLC technique proved to be selective, accurate, sensitive, and consistent in analyzing both the material content and its main degradation products.

Analytica doi: 10.3390/analytica7010012

Authors: Marianna Ntorkou Christina Patakidou Styliani Nisyriou Constantinos K. Zacharis

The rapid growth and diversification of the cosmetic industry have led to increasingly complex formulations containing numerous bioactive ingredients, excipients, and synthetic additives, often delivered through advanced nanostructured systems. Ensuring product safety, efficacy, and regulatory compliance requires analytical approaches capable of accurately detecting both declared components and hazardous contaminants such as heavy metals, phthalates, nitrosamines, and banned preservatives or dyes. Traditional sample preparation methods are often solvent-intensive, time-consuming, and environmentally burdensome, prompting a shift toward green microextraction strategies aligned with the principles of green analytical chemistry. Techniques including solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE), and dispersive liquid–liquid microextraction (DLLME) offer miniaturized, solvent-efficient workflows with improved selectivity and sensitivity for complex cosmetic matrices. This review summarizes advances from the past five years in green microextraction methods for the determination of organic and inorganic species in cosmetic products. Emphasis is placed on their integration with separation techniques and applicability across product categories. Emerging trends, analytical challenges, and future directions toward more sustainable cosmetic safety assessment are also highlighted.

Analytica doi: 10.3390/analytica7010011

Authors: Laura Favilli Valentina Isaja Paolo Inaudi Agnese Giacomino Mery Malandrino Stefano Bertinetti Egle Trincas Hatice Cansu Sezer Ornella Abollino

Molting is an important biological and physiological stage in penguins, influenced by environmental and nutritional factors. Feather composition analysis before and after molting can consequently place boundaries on element bioaccumulation and excretion. We quantified and compared elemental concentrations in African penguin (Spheniscus demersus) feathers collected pre- and post-molt across three zoos to evaluate how molt stage and zoo-specific conditions influence feather elemental composition. Feathers were retrieved from individual penguins at Zoom Torino (Italy), Overloon ZooParc (Netherlands), and Zoo Magdeburg (Germany). Quantification of elemental concentrations were performed by analytical methods, with both ICP-OES and HR-ICP-MS techniques. A statistical approach involving MANOVA and factorial analysis helped identify important trends. Pre-molt features had more variability than post-molt, with both showing significant differences in elemental concentrations. Factorial analysis showed geogenic trends in Mg, Sr, and Ni trends as well as anthropogenic trends in Pb. While Na and K differed among all treatment groups, this likely points to physiological adaptations in response to increased demand during feather regrowth. Additionally, inter-zoo comparisons highlighted distinct elemental profiles linked to local environmental and dietary conditions, particularly in Zoo Magdeburg, where Na levels were markedly elevated. This study highlights the influence of environmental and dietary conditions on feather composition during molt, offering insights for improving captive penguin welfare and broader ecological implications related to climate change and pollution.

Analytica doi: 10.3390/analytica7010010

Authors: Lucie Jurkaninová Ivan Švec Soňa Gavurníková Marcela Sluková Peter Hozlár Michaela Havrlentová

Oats (Avena sativa L.) are a rich source of β-d-glucans, dietary fibre, proteins, and lipids. However, the behaviour of these components in wheat–oat composite systems during baking, particularly with regard to matrix-dependent analytical responses, remains unclear. This study evaluated the compositional changes, technological performance, and sensory quality of wheat bread enriched with various forms of oat. Composite flours containing 5–15% wholegrain oat flour, commercial oat bran, milled commercial oat flakes, or milled sprouted oat grain (sprouted under laboratory conditions for three days at 25 °C) were prepared using the Slovakian oat cultivar ‘Peter’. The raw materials, flour blends, and baked breads were analysed for β-d-glucans (BG), total dietary fibre (TDF), starch, proteins, and lipids using standardised enzymatic, gravimetric, and polarimetric methods. Bread quality was assessed through loaf volume measurements and a sensory evaluation using a 5-point hedonic scale by seven trained panellists. Multivariate statistical analysis was applied to integrate compositional, technological, and sensory data. Compared to wheat flour (0.24% BG and 3.45% TDF), the incorporation of oats significantly increased the contents of BG, TDF, proteins, and lipids, with oat bran showing the strongest enrichment effect (owing to 15.69% TDF in the raw material). Baking induced oat-form-dependent changes in the measured BG and TDF content. The level of BG diminished in wholegrain oat blends but increased or remained stable in bran-rich systems. This reflects differences in matrix structure and analytical extractability, rather than true compositional gains. Meanwhile, starch content consistently declined across all composite breads. Fibre-rich formulations exhibited reduced loaf volume and altered both bread geometry and morphology, particularly at 15% substitution. Breads containing 5% oat flour or moderate levels of oat bran (5 or 10%) were considered the most acceptable in terms of nutritional enhancement and quality attributes. Germinated oat breads showed the greatest technological impairment and the lowest sensory scores. Overall, moderate oat enrichment strikes a balance between nutritional improvement and technological performance without significantly compromising sensory quality. These findings emphasise the significance of matrix effects when interpreting standard total dietary fibre and β-d-glucans analyses and offer an integrated analytical and technological framework for the rational design of fibre-enriched cereal products.

Analytica doi: 10.3390/analytica7010009

Authors: Francesca Sebastiani Francesca Tombolini Fabio Boccuni Claudio Natale Silvia Canepari Riccardo Ferrante

Titanium dioxide (TiO2) nano- and submicrometric particles’ widespread use in different sectors raised concerns about human and environmental exposure. The validation of analytical methods is essential to ensure reliability in risk assessment studies. In this study, a single-particle inductively coupled plasma mass spectrometry (spICP-MS) method was validated for the detection, quantification, and dimensional characterization of TiO2 particles in biological tissues. Tissue samples collected after exposure to TiO2 particles underwent mild acidic digestion using a HNO3/H2O2 mixture to achieve complete matrix decomposition while preserving particle integrity. The resulting digests were analyzed by ICP-MS operated in single-particle mode to quantify and size TiO2 particles. Method validation was conducted according to ISO/IEC 17025:2017 and included linearity, repeatability, recovery, and detection limit assessments. The limit of detection for TiO2 particles was 0.04 µg/g, and 55.7 nm was the size the detection limit. Repeatability was within 0.5–11.5% for both TiO2 mass concentrations and particle size determination. The validated method was applied to tissues from inhalation-exposed subjects, showing TiO2 levels of 80 ± 20 µg TiO2/g and particle number concentrations of 5.0 × 105 ± 1.2 × 105 part. TiO2/mg. Detected TiO2 particles’ mean diameter ranged from 230 to 330 nm. The developed and validated spICP-MS method provides robust and sensitive quantification of TiO2 particles in biological matrices, supporting its use in human biomonitoring and exposure assessment studies.

Analytica doi: 10.3390/analytica7010008

Authors: Igor E. Uflyand Anastasiya O. Zarubina Aleksandr A. Shcherbatykh Vladimir A. Zhinzhilo

The present paper reports the preparation of a nanocomposite thin film consisting of calcium itaconate and graphene oxide (GO). The composite is a black powder consisting of individual shiny prismatic crystals at varying degrees of maturity. The crystal size distribution is quite narrow: from 3.6 to 6.2 μm in length and from 0.7 to 1.1 μm in width. Thin-film-based acetone sensor made of a nanocomposite was fabricated by spin coating of calcium itaconate–GO nanoparticles on glass plates. The thin-film acetone sensor was characterized using FTIR, XRD, SEM, TEM, and the low-temperature nitrogen sorption–desorption method. The sensor response time is 7.66 ± 0.07 s (sr = 0.92%), and the relaxation time when blowing the surface with clean air or inert gas (nitrogen, argon) is 9.26 ± 0.12 s (sr = 1.28%). The sensing mechanism of the sensor for detecting acetone at room temperature was also is proposed based on phenomenological understanding due to the absence of direct electronic/charge-transport evidence.

Analytica doi: 10.3390/analytica7010007

Authors: Dagmar Remeteiová Silvia Ružičková Ľubomír Pikna Mária Heželová

Interactions between alkaline solutions and the surface of pyrolytically coated graphite tubes (PCGTs) with/without a platform for determination of vanadium using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS) are discussed. Changes on the surface of tubes, lifetime of tubes, and formation of memory effect in the determination of vanadium in alkaline solutions (NaOH, Na2CO3, and real alkaline slag leachates) were investigated. Based on the results obtained, it is possible to state that HR CS GFAAS determination of vanadium content in alkaline solutions reveals that PCGTs with a platform are more susceptible than those without a platform to the formation of deposits and degradation of the platform surface, especially after the application of hydroxide environments. More marked and faster formation of deposits leads to shortening of the analytical lifetime of PCGTs with a platform (approx. 70 atomization/analytical cycles (ACs)) compared to PCGTs without a platform (approx. 290 ACs). The mechanical life of both types of tubes is comparable (approx. 500 ACs). Deposits formed on the internal surface of PCGTs can be removed in the presence of a carbonate environment and higher temperatures. Damage to the PCGT surface leads to the formation of scaled shapes and cavities, which can result in decreased absorbance due to losses of vanadium in the cavities (negative measurement error), or in increased absorbance by washing out of vanadium from the cavities (positive measurement error, and formation of memory effect). It was found that more frequent cleaning of PCGTs by performing ACs in an environment of 4 mol L−1 HNO3 can eliminate these unfavourable phenomena. Our results have shown that in the case of samples analysed with different sample environments (acidic vs. alkaline), the surface material of the tube/platform wears out more quickly, and therefore it is necessary to include a cleaning stage after changing the nature of the environment.

Analytica doi: 10.3390/analytica7010006

Authors: Thieli Schaefer Nunes Lucas Schmidt Kayla Peterson Rosalind Wright Julio Alberto Landero-Figueroa

Iodine is essential for thyroid hormone synthesis and is particularly critical during pregnancy, where excess and mainly its deficiencies can impair fetal neurodevelopment and increase maternal complications. Bromine has also gained attention due to its potential to interfere with iodine metabolism and contribute to adverse health effects when present in excess. Monitoring iodine and bromine in biological samples, especially urine and serum, is therefore important for assessing thyroid function and population health. This work presents a simple and robust ICP-MS method for simultaneous determination of bromine and iodine in urine and serum. The procedure uses a 20-fold dilution with 10 mmol L−1 ammonia containing 0.1% (w/w) EDTA-2Na, ensuring solution stability, minimizing sample-to-sample variability, and eliminating the need for matrix-matched calibration. EDTA-2Na effectively prevents precipitation of metal species at high pH, avoiding blockages in the sample introduction system. Method accuracy was confirmed through certified reference materials and spike-recovery experiments, both showing suitable agreement for the two analytes. Precision was consistently strong (RSD < 6%), and low detection limits were achieved (0.78 μg L−1 for Br and 0.24 μg L−1 for I). The use of a high-efficiency nebulizer enabled analysis with only 50 µL of sample, making the method suitable for limited-volume specimens. Overall, this approach provides a sensitive, accurate, and practical solution for large-scale population studies and clinical applications.

Analytica doi: 10.3390/analytica7010005

Authors: Ilias Barrak Ikrame Ayouch Zineb Kassab Youness Abdellaoui Jaber Raissouni Said Sair Mounir El Achaby Khalid Draoui

The objective of this research is to develop environmentally friendly, risk-free and effective adsorbent composite beads that remove Cu(II) ions from aqueous solutions using cost-effective biopolymers (Carboxymethylcellulose (CMC) and sodium alginate (AL)). The synthesized hydrogel beads (AL@CMC) were dried using two drying modes, namely air-drying and freeze-drying, and characterized using scanning electron microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and Brunauer–Emmett–Teller (BET) analysis. The study investigated factors such as pH, adsorbent dosage, reaction time, Cu(II) ions concentration, and temperature to elucidate the adsorption mechanisms involved in removing copper ions. The results indicated that the hydrogel exhibited a maximum adsorption capacity of 99.05 mg·g−1, which is highly competitive compared to previous studies; the AL@CMC beads prepared in this work show a significantly higher adsorption capacity, improved stability due to the interpenetrated biopolymer network, and a clear enhancement from freeze-drying, which greatly increases porosity and active surface area. In addition, the pseudo-second-order nonlinear kinetic model best described the experimental data, implying the chemical nature of the adsorption process. Furthermore, the thermodynamic studies revealed that the adsorption process was endothermic, spontaneous, and homogenous. A Monte Carlo simulation model was utilized to ensure compatibility with the adsorption mechanism, in order to delve deeper into the intricacies of the adsorption process and gain a more comprehensive understanding of its underlying mechanisms and behavior. In conclusion, the prepared hydrogel beads proved to be an effective adsorbent for efficiently removing copper ions, making them a promising solution for addressing Cu(II) ion pollution.

Analytica doi: 10.3390/analytica7010004

Authors: Scarlat Ohanna Dávila da Trindade Thaís Cristina de Oliveira Cândido Matheus Martins Guedes Arnaldo César Pereira

Additive manufacturing, particularly fused deposition modeling (FDM), has emerged as a promising approach for producing electrochemical sensors based on conductive thermoplastic composites. In this study, the effects of various printing parameters (extrusion temperature, layer height and width, printing speed, and the number of conductive layers) on the electrochemical performance of PLA/CB electrodes fabricated via FDM were investigated. Electrochemical impedance spectroscopy analyses showed that properly adjusting these parameters promoted the formation of more efficient conductive pathways and reduced charge transfer resistance during monitoring of the redox behavior of the potassium ferrocyanide/ferricyanide probe. Furthermore, the electrochemical performance of the device was demonstrated through the detection of different model analytes, including dopamine, catechol, hydroquinone, paracetamol, and uric acid. The device was also applied to the determination of dopamine, achieving a detection limit of 0.16 µmol L−1. Overall, the results highlighted that optimizing printing conditions is essential for improving the electrochemical performance of 3D-printed devices, reinforcing the potential of 3D printing as a promising route for the fabrication of electrodes for electroanalytical applications.

Analytica doi: 10.3390/analytica7010003

Authors: Ignjat Filipović Snežana Stojanović Jelena Petronijević Milena Milutinović Danijela Nikodijević Nevena Petrović Marijana Kosanić Nenad Joksimović

The urgent need for effective therapies against cancer and antimicrobial-resistant pathogens motivates the development of novel metal-based complexes. Herein, we report the synthesis and characterization of four novel cobalt(II) complexes with biologically relevant β-diketo ester ligands. The complexes were characterized via UV-Vis, FTIR, mass spectrometry, and elemental analysis. Their biological activities were evaluated through antimicrobial and cytotoxic assays. Complex B1 exhibited the strongest antimicrobial activity, with minimum inhibitory concentrations (MICs) of 0.23 mg/mL against Staphylococcus aureus and Proteus mirabilis, and 0.01 mg/mL against Mucor mucedo, exceeding the performance of ketoconazole. Cytotoxicity studies on SW480 colorectal cancer cells and HaCaT normal keratinocytes identified B3 as the most potent anticancer agent (IC50 = 11.49 µM), selectively targeting tumor cells. Morphological analysis indicated apoptosis as the primary mode of cell death. Mechanistic studies were performed to elucidate interactions with biomolecules. UV-Vis and fluorescence spectroscopy, viscosity measurements, and molecular docking revealed that B3 binds strongly to calf thymus DNA via hydrophobic interactions and groove binding, and exhibits selective binding to bovine serum albumin (site II, subdomain IIIA). These results highlight the potential of cobalt(II) complexes as multifunctional agents with significant antimicrobial and antitumor activities and provide detailed insight into their molecular interactions with DNA and serum proteins.

Analytica doi: 10.3390/analytica7010002

Authors: Miriam Demtschuk Priska Heinz

In clinical medicine it is of interest to know vitamin C blood levels. There are numerous variations in published sample preparation methods for quantifying vitamin C using HPLC. For the determination of vitamin C in human probes, the method needs to be simple, fast, and accurate. A systematic search in Pubmed was carried out to identify the methods for the quantification of vitamin C with HPLC in combination with a UV detector in human plasma. A total of 83 reports were screened, from which seven methods were selected and examined in detail. Tabular overviews compare the different sample preparation options, HPLC parameters, and validation criteria. Different reagents for protein precipitation and extraction are discussed. By allowing the user to see the criteria of interest at a glance, it can be used as a tool for the rapid development and establishment of a vitamin C determination method using HPLC.

Analytica doi: 10.3390/analytica7010001

Authors: Pasant T. Elbanna Mohamed A. Hammad Inas A. Abdallah Marcello Locatelli Fotouh R. Mansour

Exploring green organic solvents is a global demand. Most of the currently used solvents pose some concerns regarding environmental sustainability and occupational health risks. In this work, propylene glycol was employed for the first time as a green solvent for mobile phase preparation in the reversed phase chromatographic separation of a mixture of two antioxidants, glutathione and ascorbic acid. The slight viscosity of propylene glycol was manipulated by using water as a co-fluidizing agent to facilitate pumping. Method optimization was performed using factorial design experimental Expert 13® Software (Minneapolis, MN, USA) to achieve the maximum resolution and the minimum run time. The reported method was properly validated according to the International Conference on Harmonization criteria at the linearity range of 1–500 µg/mL, with acceptable accuracy and precision for both drugs. The method was effectively applied for the quantification of both drugs in their commercial pharmaceutical formulation. The proposed method was assessed for environmental and operator safety by means of global tools like AGREE and MoGAPI and has proved high degrees of greenness. Propylene glycol has several benign properties, such as low volatility, less toxicity, compatibility with UV detectors and very low flammability, that will soon assemble it as a promising alternative for the conventionally used solvents.

Analytica doi: 10.3390/analytica6040059

Authors: Olga V. Levitskaya Tatiana V. Pleteneva Elena V. Uspenskaya Daria A. Galkina Daiaana D. Ogotoeva Nadezda A. Khodorovich Anton V. Syroeshkin

Quality control of herbal medicinal products (HMPs) is challenging due to their multicomponent composition. For most HMPs, chemical reference standards (CRSs) required for traditional chromatographic and spectral analyses are unavailable. According to USP and Ph. Eur., an exception is valerian tincture, for which highly specific CRSs have been developed. The aim of this study was to use principal component analysis (PCA) and the novel two-dimensional diffuse laser scattering (2D-DLS) method to identify HMPs and their aqueous-ethanolic extracts according to their botanical genera without relying on specific marker compounds. Spectral data were compiled into an extensive library covering a wide wavelength range—from 0.02 nm to 15,000 nm. PCA of the spectral data (UV spectrophotometry, fluorimetry, FTIR spectroscopy, and X-ray diffraction) enabled clustering of samples by individual botanical genera. The most significant information for sample differentiation was provided by wavenumbers of 1400, 1180, and 931 cm−1 in the IR spectra and wavelengths of 450 nm and 672 nm in the UV and fluorescence spectra, respectively. During model cross-validation, all “blind samples” were correctly classified by botanical genus, achieving a non-error rate (NER) of 100%. Furthermore, the unique 2D-DLS method was used to rapidly identify tinctures without opening the glass bottles.

Analytica doi: 10.3390/analytica6040058

Authors: Maksim N. Zavalishin Gleb A. Nikitin Vladimir S. Osokin George A. Gamov

This paper presents the design and evaluation of a fluorescent probe based on fluorescein hydrazide for the selective detection of hypochlorite (ClO−), bromide (Br−), and iodide (I−) ions in solution. The starting chemosensor, fluorescein hydrazide, is suitable for detecting hypochlorite anions in solution, as observed for the first time. The Br− and I− ions could be discovered after activating the probe with hypochlorite. Upon interaction with ClO− ions, the proposed probe exhibits a significant increase in fluorescence emission, a sharp rise in absorbance, and a distinct color change, which is attributed to the conversion from the spirolactam closed form to the open form of the fluorescein ring. ClO− and Br− ions added together were found to brominate the probe in an acetonitrile–water mixture, resulting in a pronounced bathochromic shift in both absorption and emission spectra. Notably, the combination of ClO− and I− was more effective in cleaving the spirolactam ring than hypochlorite alone. Quantum chemical calculations were used to understand the detection mechanism of Br and I ions in a probe–hypochlorite mixture. The probe demonstrated exceptional selectivity and rapid response towards the target analytes, with detection limits determined to be 2.61 μM for ClO−, 66 nM for Br−, and 13 nM for I−. Furthermore, it successfully monitored fluctuations in ClO−, Br−, and I− concentrations within complex systems, highlighting its potential application in environmental and biological monitoring.

Analytica doi: 10.3390/analytica6040057

Authors: Juan Pablo Hervás-Pérez Laura Martín-Carbajo Marta Sánchez-Paniagua

Alterations in the expression of the Klotho gene have been associated with chronic kidney disease (CKD), and its potential as an early diagnostic biomarker is currently under active investigation. In this work, we report the development of a highly sensitive, label-free electrochemical DNA-based biosensor for the detection of a 100 mer DNA fragment corresponding to a partial region of Klotho mRNA. The proposed bioplatform integrates mixed self-assembled monolayers (SAMs) and gold nanoparticles for efficient DNA immobilization within a sandwich-type configuration, coupled with impedimetric detection. Different SAM architectures were evaluated by cyclic voltammetry and electrochemical impedance spectroscopy, with the binary monolayer composed of 1-hexadecanethiol (HDT) and the capture probe (CP) exhibiting the best analytical performance. The use of gold nanoparticle-modified screen-printed carbon electrodes (AuNPs–SPCEs) resulted in a 1.4-fold increase in the signal-to-noise ratio compared to screen-printed gold electrodes. Additionally, the incorporation of a blocking step using bovine serum albumin (BSA–HDT–CP–AuNPs–SPCE) enhanced the sensitivity by 1.6-fold compared to the unblocked system. The genosensor displayed a linear response in the concentration range of 3 × 10−10 to 7.5 × 10−8 M, achieving a detection limit of 0.09 nM. Relative standard deviations below 7.5% were obtained for different Klotho concentrations, confirming high intra-assay and intermediary precision. Selectivity assays demonstrated negligible signals for non-complementary sequences, while recovery experiments in spiked human serum samples yielded satisfactory values between 96.5% and 103.4%.

Analytica doi: 10.3390/analytica6040056

Authors: Hiba Agnaou Hela Refai Spyros Grigorakis Dimitris P. Makris

Waste orange peels (WOP) are a major orange processing residue, and they may be a rich source of precious bioactive polyphenols. Amongst the various WOP constituents, hesperidin holds a prominent position as the most abundant polyphenolic metabolite, with proven biological properties. The current work was performed to provide detailed information on the effect of various acid catalysts to assist hesperidin recovery, using an ethanol organosolv treatment. The treatment developed was first examined by comparing inorganic (HCl) and natural organic (oxalic, citric) acids for their influence on process performance, extraction kinetics, and severity. Following this, optimization was accomplished through response surface methodology, and the extracts produced were investigated with respect to their polyphenolic composition and antioxidant characteristics. The HCl-catalyzed treatment, carried out with 70% ethanol/2% HCl, was proven the most efficacious, giving a total polyphenol yield of 30.7 mg gallic acid equivalents per g of dry mass, and it was shown that the treatment yield was related to severity, obeying a power model. Liquid chromatography–tandem mass spectrometry analysis of the extract generated under optimized conditions (170 min, 80 °C) revealed that hesperidin was extensively hydrolyzed into hesperetin 7-O-glucoside and aglycone (hesperetin). Such an effect was very limited with the oxalic acid-catalyzed treatment, whereas citric acid did not affect the original polyphenolic composition. Overall, the HCl-catalyzed treatment was of significantly higher performance, providing a total flavanone yield of 21.22 mg per g dry mass. The results of this investigation may be of value in adjusting treatment settings for (i) increased flavonoid recovery from WOP and (ii) producing extracts enriched in hesperidin and/or its hydrolysis derivatives. Such practical recommendations may assist the establishment of WOP valorization processes in an integrated biorefinery prospect.

Analytica doi: 10.3390/analytica6040055

Authors: Vitaliy Fomin Milana Turovets Nabira Kelesbek Assanali Ainabayev Daniyar Sadyrbekov Dauletkhan Kaykenov Askhat Borsynbayev Nurbakyt Azhibay Saule Aldabergenova

A probabilistic–deterministic design of experiments (PDDoE) approach was employed to optimize laser-induced breakdown spectroscopy (LIBS) parameters for the quantitative determination of minor components in lead-based alloys. The PDDoE optimization identified 18 J laser pump lamp energy, 1 µs delay, and 1 µs exposure as optimal conditions, minimizing spectral dispersion (5–8%) and ensuring stable plasma formation. The acquired spectra were subsequently processed in an R-based automated workflow, where Linear, Lasso, and Ridge regression models were used to establish quantitative relationships between normalized line intensities and atomic absorption spectroscopy (AAS) reference data. The resulting models demonstrated high accuracy (R2 = 0.97 for Sn, 0.985 for Sb, 0.982 for Bi, 0.919 for As, and 0.905 for Ag), with prediction errors (RMSE) below 10% and limits of quantification (LOQ) under 0.05 wt.%. Principal component analysis (PCA) applied to 43 historical (19th–20th century) and technogenic samples (19th–20th century) allowed us to isolate clusters of Pb–Sb alloys corresponding to secondary accumulator materials, alongside a diffuse group of nearly pure Pb specimens containing variable minor impurities. The combined PDDoE–LIBS–R analytical framework provides a reproducible, non-destructive, and chemometrically validated methodology for the quantitative characterization and classification of archeological and industrial lead alloys.

Analytica doi: 10.3390/analytica6040054

Authors: Keita Saito Yuki Takeuchi Hiroyuki Kataoka

Volatile organic compounds (VOCs) emitted from human skin are promising biomarkers for non-invasive health assessment and disease diagnosis. However, efficient collection and sensitive analytical methods for skin VOCs remain challenging. We developed a method for measuring ethanol, acetaldehyde, and acetone from palmar skin using glass cup aqueous sampling followed by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Compounds were extracted using a carboxen/polydimethylsiloxane fiber by HS-SPME and separated using a DB-1 capillary column within 5 min. The HS-SPME/GC-MS method showed linearity (5–1000 ng/mL, r ≥ 0.990) with detection limits of 0.56, 1.01, and 0.15 ng/mL for ethanol, acetaldehyde, and acetone, respectively. Intra-day and inter-day precision were ≤9.3% and ≤9.7%, with accuracy ranged of 94–110%. Five-minute palm contact with water caused VOC release to increase linearly, and samples remained stable for 24 h at −20 °C. Following ingestion of a 500 mL alcoholic beverage (5% ethanol), ethanol and acetaldehyde emissions peaked at 95 and 24 ng/cm2/min after 1 h, while acetone gradually increased to 1.3 ng/cm2/min after 6 h. This simple, rapid method enables practical assessment of skin VOCs for health monitoring and environmental exposure evaluation.

Analytica doi: 10.3390/analytica6040053

Authors: Jiawei Xu Tatsuya Fujino

We have developed mold matrices that can be employed to distinguish between enantiomers (D- and L-glucose) and structural isomers (n- and iso-stearic acid) in matrix-assisted laser desorption/ionization mass spectrometry. Utilizing a temperature-responsive polymer, a molecular structure recognition film was created around metal or semiconductor particles, such as silver (Ag) or cadmium telluride (CdTe), forming the core. Molecules that fit the template structure were selectively ionized. To elucidate the properties of the mold matrix, the relationship between molecular recognition rate and peak intensity of analyte ion was investigated by varying polymer film thickness around the core. The relationship between molecular recognition rate and hydrophobicity of the template molecule was also examined. It was found that increasing the amount of polymer forming the molecular recognition film improved the molecular recognition rate. However, the peak intensity of the analyte ion decreased. It was also found that using highly hydrophobic molecules as template molecules resulted in high molecular recognition rates. In addition, a water-splitting photocatalyst was synthesized and utilized to fabricate the mold matrix. It was applicable to both positive and negative ion generation while recognizing the molecular structure of the analyte.

Analytica doi: 10.3390/analytica6040052

Authors: Amalia Ridichie Adriana Ledeţi Cosmina Bengescu Laura Sbârcea Răzvan Adrian Bertici Denisa Laura Ivan Gabriela Vlase Titus Vlase Francisc Peter Ionuţ Ledeţi

Estrogens are cholesterol-derived hormones, with four endogenous estrogens being presented in the scientific literature, namely, estradiol, estrone, estriol, and estetrol. In this study, we aim to obtain a complete thermoanalytical profile for the three most important endogenous estrogens: estradiol, estriol, and estrone. To achieve this, the TG/DTG were registered in non-isothermal conditions at five different heating rates (β = 2, 4, 6, 8, and 10 °C min−1). To describe the mechanisms of the degradation processes, a complex kinetic analysis was performed by applying a preliminary method (ASTM E698), two isoconversional methods (Flynn–Wall–Ozawa and Friedman), and the non-parametric kinetic method. The results indicate that estradiol undergoes a single-step degradation process, while estriol and estrone present a complex degradation process. The determination of the shelf life of pharmaceutical products represents a critical factor in ensuring their safety and efficacy. This parameter can be estimated from the activation energy derived from non-isothermal experiments through the application of the Arrhenius equation and appropriate kinetic models.

Analytica doi: 10.3390/analytica6040051

Authors: Ebenezer O. Olaniyi Christopher Kucha Fanbin Kong

Nuts such as pecans, almonds, peanuts, pistachios, and walnuts are nutrient-dense foods rich in unsaturated fatty acids and antioxidant compounds. Their regular consumption has been linked to significant health benefits, including reduced risks of cardiovascular disease, diabetes, and high cholesterol. With increasing global demand, ensuring the quality of nuts before they reach consumers is critical. Conventional quality assessment methods dominate the industry but are often subjective, destructive, time-intensive, environmentally burdensome, and laborious. Therefore, there is an urgent need for rapid, non-destructive, and objective alternatives capable of meeting modern quality standards. In this systematic review, we summarize traditional approaches for evaluating nut quality parameters and introduce hyperspectral imaging as a novel technique with promising applications. We examine its use in detecting nut adulteration, assessing chemical composition, identifying defects, and evaluating other quality traits. Limitations of hyperspectral imaging in industrial settings are also discussed, along with potential solutions and future directions. Given the relatively limited research area, approximately 44 relevant studies were critically reviewed. This work provides valuable insights for researchers and industry stakeholders developing innovative technologies for nut quality assessment.

Analytica doi: 10.3390/analytica6040050

Authors: Peera Tabboon Ekapol Limpongsa Rapee Jarungsirawat Supawan Wechprakhon Jidapa Niyommoh Amika Wantong Napaphak Jaipakdee

A high-performance liquid chromatography method coupled with diode array detection (HPLC-DAD) was developed for simultaneous quantification of andrographolide (AG) and 14-deoxy-11,12-didehydroandrographolide (DDAG) in rat plasma. A salt-assisted liquid–liquid extraction (SALLE) procedure was optimized, with MgSO4 yielding the highest extraction efficiency (>90% for both AG and DDAG), outperforming conventional solvent extraction, and being comparable to solid-phase extraction. The method exhibited acceptable linearity (125–2000 ng/mL, R2 > 0.99), with low limits of detection and quantification of 60 and 70 ng/mL for AG and 201 and 234 ng/mL for DDAG, respectively, while adhering to the ICH M10 criteria for accuracy, precision, and stability under various storage conditions. Stability testing of the prepared samples demonstrated that >99% AG and 95% DDAG were retained when stored at low temperatures, specifically below 4 °C. The developed method was successfully applied in a pharmacokinetic study following oral administration of Andrographis paniculata extract (containing AG 7.5 mg/kg) to healthy Wistar rats. The SALLE-HPLC-DAD method developed herein enables selective AG quantification without significant matrix interference. In conclusion, this study introduces an alternative sample preparation and analytical method that is fast, cost-effective, and reliable, making it suitable for pharmacokinetic studies of the principal biomarker of Andrographis paniculata.

Analytica doi: 10.3390/analytica6040049

Authors: Luoana Florentina Pascu Valentina Andreea Petre Vasile Ion Iancu Ioana Antonia Cimpean Florentina Laura Chiriac

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants that tend to accumulate in solid matrices such as sewage sludge, raising concerns regarding their fate and potential ecological risks. This study aimed to develop and validate a robust analytical method for the accurate determination of PFAS in dehydrated sludge. A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was optimized for 28 PFAS, including perfluoroalkyl carboxylic acids (PFCAs) and sulfonic acids (PFSAs). Solid–liquid extraction with basic methanol was followed by cleanup using a cartridge packed with ferrite and sodium sulfate to remove moisture and particulate interferences. Chromatographic separation was performed with an Avantor® ACE® PFAS Delay column coupled to an Agilent triple quadrupole MS operating in negative electrospray ionization mode. The method achieved excellent sensitivity (MDL < 0.02 µg/g dry weight for most compounds), satisfactory precision (RSD < 15%), and recoveries between 80–118%. Optimization of mobile phase additives, gradient conditions, and MS parameters enhanced chromatographic resolution and signal-to-noise ratio. The validated method demonstrates high reliability for PFAS determination in complex solid matrices and can be applied as a valuable tool for environmental monitoring and risk assessment of sludge management practices.

Analytica doi: 10.3390/analytica6040048

Authors: Abraham Kabutey Su Su Soe Mahmud Musayev Sonia Habtamu Kibret

The study evaluated the effect of moderate heating temperatures on physical, mechanical, and spectral properties of bulk flaxseeds and pressed oils. The samples of bulk flaxseeds were measured at 60 mm pressing height and subjected to pretreatment temperatures between 40 °C and 60 °C at 5 °C intervals at a constant heating time of 30 min. The uniaxial compression process, comprising a pressing chamber of a diameter of 60 mm with a plunger, was used for extracting the oil under a load of 300 kN and a speed of 5 mm/min. Prior to the oil extraction, the moisture content of the flaxseeds samples was determined to be 8.15 ± 0.07% d.b., and that of oil content was 40.32 ± 0.02%. Based on the results obtained, porosity, density, oil yield, and oil expression efficiency significantly correlated positively (p-value < 0.05) with the increase in heating temperatures. However, kinematic and dynamic viscosities, compressive stress, deformation energy, and hardness did not significantly correlate (p-value > 0.05) with heating temperature. The study revealed that heating temperatures increased oil yield from 11.54% to 24.18% and oil expression efficiency from 28.62% to 59.96% with the corresponding deformation energy of 0.698 ± 0.011 kJ at 60 °C. The findings suggest that mild thermal pretreatment of flaxseeds improves oil recovery with minimal energy requirement under the linear compression process.

Analytica doi: 10.3390/analytica6040047

Authors: Julio C. Avalos Eugenia Aldeco-Pérez Julieta Torres-González Raul Garcia-Garcia German Orozco

Major vibrational spectroscopy studies have focused on the preparation of chromium coatings via chemical processes (conversion coatings), and few studies have focused on electrochemical processes (electrodeposition). Initially, the chemical precursors were hexavalent chromium salts, but these compounds are now replaced by less toxic trivalent ions. There is a profound understanding of the process when vibrational spectroscopy is used in combination with other techniques. This is the case for chromium(VI) conversion coatings, and the results of several techniques, such as synchrotron infrared microspectroscopy, have made it possible to understand the structure of the two-layer coating and the chemical composition of each layer. Vibrational spectroscopy confirmed the mechanism for coating formation, in which ferricyanide was a redox mediator. In addition, vibrational spectroscopy was effective in determining the mechanism of corrosion resistance of the coatings. Conversely, there are very few studies on the electrodeposition of trivalent chromium ions, and the mechanics of electrodeposition are unknown. To simplify the use of spectroscopy, spectra of potassium dichromate and chromium(III) sulfate are presented as references for coating studies, and a compilation of Cr(III)−O and Cr(VI)−O vibrational modes is provided to facilitate band assignment. Our review highlights that spectroscopic techniques have been insufficiently applied in this field; however, the results of vibrational spectroscopy accelerate the transition to safer Cr(III) technology.

Analytica doi: 10.3390/analytica6040046

Authors: Olivia-Stella Salm Jaan Kers Maria Kulp

In modern circular-economy value chains, wood is frequently processed into fines, chips, or powders—forms in which anatomical features are no longer visible, rendering traditional visual identification methods ineffective. This study introduces a rapid, non-destructive attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopy approach, combined with chemometric modeling, to address this challenge by enabling both the classification and compositional profiling of processed wood fractions. Using full-spectrum ATR-FTIR data, partial least squares discriminant analysis (PLS-DA) models achieved high-accuracy classification of wood by type, species, and provenance, with sensitivity and specificity reaching up to 1.00. In addition, PLS and backward interval BiPLS models predicted total lignin, acid-soluble lignin, and extractives with strong performance (R2 > 0.90, RPD > 2). Interval selection further enhanced prediction accuracy by reducing RMSEP by up to 30%, improving model stability for real-world application. By replacing slow, reagent-intensive wet chemistry with a rapid, green, and scalable technique, the presented methodology provides a valuable tool for authentication, quality control, and resource optimization when dealing with mechanically processed or recycled wood.

Analytica doi: 10.3390/analytica6040045

Authors: Huijun Wang Yuangui Yang Yueyi He Hongbo Xu Shizhong Chen

In this study, an integrated analytical method coupling ultra-high-performance liquid chromatography–photodiode array detection–quadrupole time-of-flight mass spectrometry with total antioxidant capacity determination (UHPLC-PDA-Q-TOF/MS-TACD) was developed for the rapid screening and identification of antioxidants in complex natural extracts. The system enables simultaneous chromatographic separation, mass spectrometric characterization, and on-line activity assessment by combining 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and ferric ion reducing antioxidant power (FRAP) assays. When applied to Rosa rugosa samples from five different origins, the approach efficiently separated the extract and successfully localized antioxidants directly from the chromatographic profile. A total of 86 compounds were identified, including flavonoids, tannins, and phenolic acids. Among them, 60 exhibited free radical scavenging capacity and 59 showed reducing activity. Activity verification experiments showed that all seven compounds exhibited good antioxidant activity. The IC50 values of gallic acid, ellagic acid, quercetin 3-O-rhamnoside, and rutin were 0.019, 0.025, 0.043, and 0.046 mM, respectively, which were significantly better than the positive control (vitamin C). This method provides methodological and technical support for the rapid discovery of antioxidant components in complex natural products.

Analytica doi: 10.3390/analytica6040044

Authors: Sara Madji Julien Antih Malak Tabib Charlotte Silvestre Anissa Ghennai Audrey Warnery Fabrice Vaillant Florence Bichon Aude Echalier Patrick Poucheret

In recent years, research and development in the field of green extraction of bioactive compounds from plants has intensified. This increased focus is driven by market trends, environmental concerns, and consumers’ growing interest in natural and healthy ingredients, as well as bioactive compounds. This development aligns with a global trend toward more sustainable use of natural resources. In this context, macroalgae have been recognized as valuable sources of bioactive compounds with various health benefits. These molecules include proteins, fatty acids, vitamins, and pigments. Phycobiliproteins (PBPs) are pigments and metabolites of particular interest that can be extracted from microalgae. This group of colored proteins, mainly present in cyanobacteria and red algae, is known to have a wide range of potential applications. However, conventional methods for extracting PBPs, such as homogenization, maceration, and freezing, are time-consuming and energy-intensive, often producing unsatisfactory yields. As a result, new extraction technologies have been developed, including ultrasound-assisted extraction, ionic liquid extraction methods, and the use of natural deep eutectic solvents. This review summarizes existing green processes for extracting and purifying PBPs, with the aim of enabling feasible and sustainable valorization of algae. Specifically, it covers various extraction and purification techniques of PBPs, as well as the effects of environmental growth conditions on the production of these metabolites. It also highlights the biological and pharmacological activities of PBPs and explores their potential applications in the food, cosmetic, and biomedical sectors.

Analytica doi: 10.3390/analytica6040043

Authors: Ardiana Topi Agim Kasaj Daniel Hudhra Hasim Kelebek Gamze Guclu Serkan Selli Dritan Topi

Wine phenolics serve as robust chemical signatures correlated to grape variety, processing, and regional identity. This study explores the potential of machine learning algorithms, combined with the phenolic profiles of Albanian wines, to classify them according to grape variety. Geographic origin analysis was conducted as a preliminary exploration. The dataset of phenolic compounds included white and red wines, spanning the 2017 to 2021 vintages. Using five supervised algorithms—Support Vector Machine (SVM), Random Forest, XGBoost, Logistic Regression, and K-Nearest Neighbors—a high classification accuracy was achieved, with SVM reaching 100% under Leave-One-Out Cross-Validation (LOOCV). To address class imbalance, the Synthetic Minority Over-sampling Technique (SMOTE) and stratified cross-validation were applied. Random Forest feature importance consistently highlighted trans-Fertaric acid and Procyanidin B3 as dominant discriminants. Parallel coordinates plots demonstrated clear varietal patterns driven by phenolic differences, while PCA and hierarchical clustering confirmed unsupervised grouping consistent with wine type and maceration level. Permutation testing (1000 iterations) confirmed the non-randomness of model performance. These findings show that a small set of phenolic markers can offer high classification accuracy, supporting chemically based wine authentication. Although the dataset is relatively small, thorough cross-validation, non-redundant modeling, and chemical interpretability provide a solid foundation for scalable methods. Future work will expand the dataset and explore sensor-based phenolic measurement to enable rapid authentication in wine.

Analytica doi: 10.3390/analytica6040042

Authors: Ayşe Pınar Yağcılar Emre Şefik Çağlar Neslihan Üstündağ Okur

This study was designed for the analytical method development and validation for Calcium butyrate (CAB) using High-Performance Liquid Chromatography (HPLC). 1H and 13C Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) spectroscopy analysis were carried out to examine the molecular structure. For HPLC analysis, a blend of acetonitrile and phosphoric acid solution (0.1%) (20:80) (v/v) was used as a mobile phase. A C18 column (5 µm, 250 × 4.6 mm) was used as a stationary phase. The eluent of CAB was monitored with a UV detector at a wavelength of 206 nm and a flow rate of 1 mL/min. According to the results, FTIR and NMR spectra were consistent with the structural characteristics of CAB, and the expected proton and carbon signals were observed. During the HPLC analysis, due to the ionization of CAB, three distinct retention times were observed in the chromatograms at 3.4, 4.5, and 7.4 min. The validation was performed according to ICH guidelines. The obtained results demonstrated that the analytical method was successfully validated, with LOD values of 1.211, 0.606, and 1.816 µg/mL, and LOQ values of 3.670, 1.835, and 3.676 µg/mL. The assay displayed a linear range of 5–1000 µg/L concentration and was found suitable for further formulation content analysis.

Analytica doi: 10.3390/analytica6040041

Authors: Maxime Chivaley Samia Bassim Vicmary Vargas Didier Lartigue Brice Bouyssiere Florence Pannier

As one of the world’s most widely used packaging materials, paper obtains its properties from its major component: wood. Variations in the species of wood result in variations in the paper’s mechanical properties. The pulp and paper production industry is known to be a polluting industry and a consumer of a large amount of energy but remains an essential heavy industry globally. Paper production, based largely on the kraft process, is mainly intended for the food packaging sector and, thus, is associated with contamination risks. The lack of standardized regulations and the different analytical techniques used make information on the subject complex, particularly for inorganic elements where little information is available in the literature. Most research in this field is based on sample preparation using mineralization via acid digestion to obtain a liquid and homogeneous matrix, mainly with a HNO3/H2O2 mixture. The most commonly used techniques are Atomic Absorption Spectrometry (AAS), Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), each with its advantages and disadvantages, which complicates the use of these tech-niques for routine analyses on an industrial site. In the same field of inorganic compound analysis, Microwave Plasma Atomic Emission Spectrometry (MP-AES) has become a real alternative to techniques such as AAS or ICP-AES. This technique has been used in several studies in the food and environmental fields. This publication aims to examine, for the first time, the state of the art regarding the analysis of inorganic elements in food packaging and different matrices using MP-AES. The entire manufacturing process is studied to identify possible sources of inorganic contaminants. Various analytical techniques used in the field are also presented, as well as research conducted with MP-AES to highlight the potential benefits of this technique in the field.

Analytica doi: 10.3390/analytica6040040

Authors: Suhail Alghanem Ewelina Dziurkowska

(1) Background: Caffeine is one of the most widely consumed psychoactive substances. Its safety profile and short half-life make it an ideal drug model for studying the pharmacokinetics of caffeine. This study aimed to develop a method for determination of caffeine in a small volume of saliva (200 µL). (2) Methods: Solid-phase extraction was employed to isolate caffeine from saliva, followed by quantitative analysis using liquid chromatography coupled with diode-array detection. Chromatographic separation was achieved on a C18 column, using a gradient mobile phase of acetonitrile and 0.1% formic acid. (3) Results: The method was validated for selectivity, linearity, precision, and accuracy. Linearity was established over the range of 10–10,000 ng/mL (R2 = 0.995). The coefficients of variation for intra- and inter-day precision for the three tested caffeine concentrations did not exceed 12.11%. Recovery from spiked saliva samples exceeded 90.53%. The developed method was applied to preliminary studies to follow the pharmacokinetics of caffeine in saliva. The concentration of the substance was studied in the saliva obtained from a volunteer after espresso consumption. (4) Conclusions: The developed method will offer a reliable approach for non-invasive caffeine monitoring in clinical and research applications.

Analytica doi: 10.3390/analytica6040039

Authors: David Kleiner David Muscatiello Zugeily Gutierrez Vanessa Asare Yong Guo

Nucleosides are of significant interest to biomedical and pharmaceutical research and have been successfully separated in hydrophilic interaction liquid chromatography (HILIC). However, there have been few studies focusing on the retention mechanisms, and detailed retention mechanisms are not clearly understood. The quantitative assessment methodology based on the linear relationship between the observed retention factors and the phase ratio has been shown to be a new tool to investigate the retention mechanisms of polar compounds in HILIC. This study evaluated the retention mechanisms of 16 nucleosides on a bare silica column. The retention contributions by partitioning, adsorption, and electrostatic attractions are quantitatively determined, and the main retention mechanism can be unambiguously identified for each nucleoside. The study results indicate that the main retention mechanism can shift with the salt concentration in the mobile phase, but partitioning seems to dominate at higher salt concentrations. In addition, the partitioning coefficients are measured using the quantitative assessment methodology and have a relatively strong correlation with the log P values of the nucleosides. Considering large errors in the log P values for these very polar compounds, the partitioning coefficients measured experimentally in the HILIC system may provide a more accurate measure for polarity assessment.

Analytica doi: 10.3390/analytica6040038

Authors: Slađana V. Dončić Dragan Z. Troter Miroslav M. Sovrlić Nebojša D. Zdravković Aleksandar G. Kočović Miloš N. Milosavljević Milos Stepovic Emina M. Mrkalić Jelena B. Zvezdanović Dušica P. Ilić Sandra S. Konstantinović

Significant depletion of natural resources, coupled with increased environmental pollution resulting from the constant evolution of global industrialization, poses a considerable problem. Therefore, it is unsurprising that sustainable “green” chemistry and technology are gathering the worldwide scientific community, whose common goal is to find applicable solutions for the abovementioned problems. This paper combined the ultrasonic extraction method (a form of “green” technology) with natural deep eutectic solvents (NADESs, a type of “green” solvent) for the production of extracts from an industrial by-product (discarded waste wild apple dust). Waste wild apple dust was pretreated with different NADESs in order to explore the pretreatment benefits regarding ultrasonic extraction of bioactive compounds. Among all solvents used, aqueous propylene glycol was chosen as the best system, which, combined with Reline NADES pretreatment, provided the highest TPC and TFC values, together with the best antioxidant activities. UHPLC-DAD-MS analyses of extracts revealed the presence of natural organic acids, quercetin and kaempferol derivatives, tannins, and flavones. Following this procedure, valorization of agro-industrial apple herbal waste resulted in obtaining extracts with high potential for utilization in different industrial branches (food and pharmaceutical industries), contributing to both cleaner production and reduced environmental impact.

Analytica doi: 10.3390/analytica6030037

Authors: Piyanat Issarangkura Na Ayutthaya Chanchana Thanachayanont Khan-Un Thongdeevimornwong Tanagorn Sirisakulchaiyaporn Patinya Khummanee Nattawadee Wisitruangsakul Monnapat Vongboot

The synthesis of new molecularly imprinted polyurethane foam (MIPUF) using an herbicide of atrazine (Atz) as a template for selective solid-phase extraction for Atz was proposed for the first time. The MIPUF was simply synthesized under mild conditions, without requiring an oxygen-free environment. Some household apparatuses were adapted for the preparation, such as a plastic cup and bamboo chopstick. The ready-to-use MIPUF minicolumns could be obtained within 4 h with more than 10 minicolumns. The proposed material was characterized using FT-IR and SEM. The MIPUF minicolumn was used in a solid-phase extraction. The eluate of free Atz was determined using the fluorescence technique without further derivatization at 343 nm. The MIPUF offered a good sensitivity and selectivity over non-molecularly imprinted polyurethane foam (NIPUF), enhancing fluorescence intensity by 15.6 times. The linear equation and linear range for Atz detection at y = 87.25x + 311.58, R2 = 0.9887 and 0.2–1.0 µM were obtained. The LOD and LOQ were 35 and 110 nM, respectively. The MIPUF revealed a more selective Atz than some potential pesticides. The ready-to-use minicolumn has been used for sample preparation and Atz assays in surface water in orchards and river water samples with recoveries (%) at 90–110%.

Analytica doi: 10.3390/analytica6030036

Authors: Emrah Kirtil

Pesticide residue violations continue to challenge the compliance of Turkish horticultural exports with European Union food safety regulations. This study examined 1138 RASFF alerts (1660 detections) issued between 2020 and 2025 using statistical enrichment, time-series modeling, and unsupervised machine learning. Pepper was the most frequently rejected commodity, with strong enrichments of formetanate (71-fold), pyridaben (35-fold), and acetamiprid (5-fold). Notably, chlorpyrifos and chlorpyrifos-methyl remained among the most commonly detected residues despite EU bans, suggesting continued use of stockpiled or illicit products and prolonged environmental persistence. Rejections peaked during winter and spring, particularly for citrus and greenhouse-grown crops. Clustering and association rule mining revealed modular commodity–pesticide structures and recurrent co-detection patterns. Anomaly detection further identified discrete periods of irregular contamination. Overall, the results indicate that violations are seasonally patterned and structurally embedded. Targeted monitoring aligned with crop calendars and stricter enforcement of legacy pesticide phase-outs could significantly improve compliance and reduce export rejections.

Analytica doi: 10.3390/analytica6030035

Authors: Heru Agung Saputra Demas Aji Badrut Tamam Ibnu Ali Asranudin

Fundamental research, exploration, extraction, and metallurgical studies of rare earth elements (REEs) require the use of analytical techniques. Recently, emerging developments of analytical instrumentation for REEs have taken place, with some of them having shrunk in size, becoming handheld devices. The Flame and Graphite Furnace AAS, ICP-OES, and MP-AES are standard laboratory techniques used for the analysis of REEs. ICP-MS, ICP-MS/MS, ICP-TOF-MS, HR-ICP-MS, MH-ICP-MS, and MC-ICP-MS are popular techniques for REE analysis thanks to their ultrahigh sensitivity, minimal interference effects, and broad applicability. The INAA, XRF, LIBS, and LA-based ICP-MS techniques are widely employed for the direct analysis of solid samples. The TIMS, SIMS, and SHRIMP are common techniques used for dating isotopic REE deposits. The portable XRF, LIBS, and Raman spectrometer devices can perform on-the-spot in situ analysis, which may help make speedy decisions in the exploration study of REEs. Currently, hyperspectral remote sensing platforms, such as handheld, drone, and satellite-based devices, are preferred for the exploration of REEs due to their cost-effectiveness, which enables the coverage of large areas in a limited amount of time. The use of microanalytical sensors installed on remotely operated vehicles has been successfully applied in analyzing rich REE-bearing deposits in the deep sea. In general, this review provides in-depth information on all essential aspects, from analytical instruments to cutting-edge developments in the analysis of REE-bearing resources.

Analytica doi: 10.3390/analytica6030034

Authors: Maria Tarapoulouzi Małgorzata Ruggiero-Mikołajczyk Ioannis Pashalidis Charis R. Theocharis

Halloumi cheese, a traditional Cypriot dairy product with Protected Designation of Origin (PDO) status, is renowned for its unique texture and high melting point. PDO certification is crucial for Halloumi cheese as it ensures the product’s authenticity, protects its traditional production methods and geographical origin, and safeguards consumers and producers against fraud and mislabeling. However, concerns over adulteration, particularly through the addition of skim milk powder, pose challenges to its authenticity and quality control. This study is the first to analyze Halloumi cheese using Brunauer–Emmett–Teller (BET) analysis and Fourier Transform Infrared (FTIR) spectroscopy, providing a novel approach to assessing its composition and authenticity. Furthermore, it marks the first time Halloumi samples have been examined in the context of PDO certification. Alongside PDO-certified Halloumi, two additional sample sets were produced following PDO specifications for moisture, fat, and salt content, with the controlled incorporation of skim milk powder as an adulterant at concentrations of 1% and 5%. Principal component analysis (PCA) was employed to visualize and interpret the spectral data, revealing promising results. Chemometric analysis showed that the specific surface area from BET measurements and the FTIR spectral subregion between 1650 and 1100 cm−1 were key factors, and they were retained for model construction. These findings could play a crucial role in establishing official food fraud detection methodologies, particularly for the Cyprus and EU markets. While this study serves as an initial investigation, additional samples will be tested in future studies to validate these preliminary results and to assess the potential of applying these techniques in real-world food fraud detection scenarios.

Analytica doi: 10.3390/analytica6030033

Authors: Saulo Alves de Souza Cristiane dos Reis Feliciano Grazielle Cabral de Lima Ítalo Agnis da Silva Gomes Nathália Carvalho Costa Bruno Alves Rocha Mariane Gonçalves Santos

The contamination of food and beverages with heavy metals, such as Cd, presents significant health risks, underscoring the need for reliable and sensitive analytical methods. This study introduces the development of a rapid, cost-effective, and environmentally friendly method for Cd determination in cachaça, a traditional Brazilian sugarcane spirit. Magnetic nanoparticles (Fe3O4) functionalized with tetraethyl orthosilicate are synthesized and employed as adsorbents in a dispersive magnetic solid-phase extraction procedure. The extracted Cd is quantified using flame atomic absorption spectrometry. A full factorial experimental design is used to optimize key parameters, including the sorbent mass, adsorption time, desorption time, and acid concentration. The method demonstrates excellent analytical performance, with a linear calibration range (R2 = 0.99), detection limit of 0.0046 mg L−1, and quantification limit of 0.0200 mg L−1. Moreover, validation results show high precision (coefficient of variation < 9.10%) and accuracy (recovery rates between 92.00% and 120.00%). When analyzing commercial cachaça samples, cadmium was detected in all five specimens. Notably, in one sample the cadmium concentration exceeded Brazil’s maximum permissible limit of 0.0200 mg kg−1, underscoring the importance of this work for ensuring food safety. The proposed method offers a sensitive, reproducible, and sustainable approach for analysis of potentially toxic trace metals in alcoholic beverages, reinforcing its potential for routine monitoring and regulatory compliance.

Analytica doi: 10.3390/analytica6030032

Authors: Dritan Topi Hasim Kelebek Gazmend Shehi Gamze Guclu Serkan Selli

Merlot red wines rank among the most distinguished varietals globally. This study aimed to characterize the phenolic compound profiles of Merlot wines and assess the influence of geographical origin and vintage on samples from two Albanian wine regions. Using liquid chromatography coupled with tandem mass spectrometry, a total of 31 phenolic compounds were identified and quantified. These were classified into hydroxybenzoic acids and flavan-3-ols (13 compounds), phenolic acids (9), flavonols (5), and stilbenoids (4). The total phenolic content ranged from 294 mg L−1 in wines from the Mati–Mirdita region to 480 mg L−1 in those from the Durrës–Kavaja region, demonstrating significant regional variation. Notably, the hydroxybenzoic acids and flavan-3-ols exhibited the most pronounced differences, with gallic acid concentrations varying from 123 mg L−1 (Mati–Mirdita) to 170 mg L−1 (Durrës–Kavaja). Both regions’ wines were rich in catechin, epicatechin, procyanidin derivatives, trans-caftaric acid, and ethyl gallate. However, procyanidins were found in higher concentrations in the Mati–Mirdita wines, while other phenolics were more abundant in Durrës–Kavaja samples. These findings underscore the influence of geographical and climatic factors on phenolic composition, offering a robust chemical fingerprinting approach for assessing wine authenticity and quality.

Analytica doi: 10.3390/analytica6030031

Authors: Angel Nikolov Nely Grozeva Miroslav Vasilev Daniela Orozova Zlatin Zlatev

The growing demand for functional bakery products necessitates research on the enrichment of wheat bread with pigweed (Amaranthus spp.) and purslane (Portulaca oleracea) flour. Although these plant-based raw materials offer nutritional and environmental benefits, their inclusion in wheat bread formulations poses challenges in the creation of formulations that may compromise the sensory and structural qualities of the final product. The main objective of this work is to systematically determine the optimal amounts of these alternative flour using multimodal bread characterization techniques that include physicochemical, organoleptic, geometric, and optical evaluations, supported by advanced data reduction techniques and regression models. A total of 70 features were analyzed and reduced to 22 for pigweed flour and 15 for purslane flour informative features. Predictive models (R2 = 0.85 for pigweed flour, R2 = 0.84 for purslane flour) were developed to optimize the inclusion of alternative flour, resulting in appropriate concentrations of 3.69% for pigweed flour and 7.13% for purslane flour. These formulations balance improved nutritional profiles with acceptable sensory and structural properties. The results obtained not only complement the potential of pigweed and purslane as sustainable functional raw materials but also demonstrate the efficacy of an automated, image-based approach to formulating recipes in food manufacturing.

Analytica doi: 10.3390/analytica6030030

Authors: Najlae El Bouanani Bouchaib Bencharki Hafsa Houmairi

This study analyzes the nutritional quality and mycotoxin contamination of three key feed ingredients—corn, soybean meal (SBM), and sunflower meal (SFM)—imported into Morocco during the years 2019, 2020, and 2021. Samples were collected upon reception at the plant and analyzed in triplicate under standardized laboratory conditions. Chemical composition was evaluated using classical and NIR-based methods, while mycotoxin levels were assessed through ELISA and confirmed by HPLC. Corn samples from Argentina, Brazil, and Ukraine were assessed for their proximate composition and mycotoxin burden. While most nutritional parameters showed no significant differences between origins (p > 0.05), water activity (Aw) and digestible threonine content were significantly affected by origin (p < 0.01). Brazilian corn had the highest Aw (0.716), followed by Argentina (0.680), and Ukraine (0.662), a factor linked to its higher susceptibility to mold and mycotoxin development. Soybean meal from the U.S. and Argentina showed a general positive trend in favor of U.S. imports, with higher average crude protein (the CP content of American soybean meal was 46.912%, compared to 46.610% in Argentine soybean meal), fat, digestible lysine, and metabolizable energy. However, statistical differences were limited to water activity and moisture content (p < 0.05). American soybean meals are generally recognized for their consistent processing quality and superior amino acid digestibility. Sunflower meal, sourced exclusively from Ukraine, showed a steady improvement in crude protein (from 35.97% in 2019 to 36.99% in 2021) and metabolizable energy, alongside reduced crude fiber content, enhancing its nutritional value in poultry diets. The consistent use of Ukrainian SFM in Morocco reflects both supply stability and quality. Regarding mycotoxins, origin had a significant effect on several compounds. Argentine and Brazilian corn showed higher mean levels of fumonisins (1165.26 and 1019.52 ppb), ochratoxin A (2.26 and 3.02 ppb), and zearalenone (36.99 and 21.92 ppb) compared to Ukrainian corn, which consistently had the lowest levels across all major mycotoxins (e.g., fumonisins = 200 ppb; zearalenone = 4.90 ppb). Aflatoxin B1 levels remained constant at 0.2 ppb across all origins. These findings confirm the influence of geographic origin—particularly water activity—on mycotoxin risk in imported maize.

Analytica doi: 10.3390/analytica6030029

Authors: Jinan Sabsabi Andressa Adame Francis Vanier Nii Patterson Allan Feurtado Aïssa Harhira Mohamad Sabsabi François Vidal

Rapid and accurate assessment of nutritional quality, particularly crude protein content and essential nutrient concentrations, remains a major challenge in the food and feed industries. In this study, laser-induced breakdown spectroscopy (LIBS) was combined with advanced chemometric modeling to predict the levels of crude protein and key macro- and micronutrients (Ca, Mg, K, Na, Fe, Mn, P, Zn) in 61 barley forage samples composed of whole aerial plant parts ground prior to analysis. LIBS offers a compelling alternative to traditional analytical methods by enabling real-time analysis with minimal sample preparation. To minimize interference from atmospheric nitrogen, nitrogen spectral lines were excluded from the protein calibration model in favor of spectral lines from elements biochemically associated with proteins. We compared the performance of Partial Least Squares (PLSR) regression and Extreme Learning Machine (ELM) using fivefold cross-validation. ELM outperformed PLS in terms of prediction, achieving a coefficient of determination (R2) close to 1 and a ratio of performance to deviation (RPD) exceeding 2.5 for proteins and several nutrients. These results underscore the potential of LIBS-ELM integration as a robust, non-destructive, and in situ tool for rapid forage quality assessment, particularly in complex and heterogeneous plant matrices.

Analytica doi: 10.3390/analytica6030028

Authors: Julia D. Bryantseva Marina O. Gorbunova Vladimir A. Zhinzhilo Igor E. Uflyand

The reaction of zirconium tetrachloride with 2-amino-1,4-benzenedicarboxylic acid in N,N-dimethylformamide with the addition of HCl leads to the formation of zirconium 2-amino-1,4-benzenedicarboxylate. Zirconium 2-amino-1,4-benzenedicarboxylate was characterized by elemental analysis, infrared spectrometry, X-ray diffraction, scanning electron microscopy, and volumetric nitrogen adsorption/desorption. The sample has a constant porosity with an average pore diameter of 7.97 nm and both microporous and mesoporous structure with a large surface area (820 m2/g) corresponding to the type IV adsorption. Zirconium 2-amino-1,4-benzenedicarboxylate was used for solid-phase extraction (SPE) of chlortetracycline hydrochloride from the aqueous solution. The obtained results confirmed the possibility of using the proposed analytical technique as a new, convenient approach to the extraction of chlortetracycline hydrochloride from industrial or other wastewaters, where such substance is contained in insignificant concentrations and its determination requires expensive and complex equipment. In the future, this method can be used not only for the effective removal of pollutants from industrial wastewater with subsequent regeneration of the sorbent, but also as a sample-preparation method for concentrating chlortetracycline hydrochloride from dilute solutions with its subsequent elution and analysis by available methods, for example, spectrophotometry, since the limit of detection is 0.06 mg/L. Experimental data are described by the isotherm of SPE (R2 = 0.998–0.999) and show the ability of zirconium 2-amino-1,4-benzenedicarboxylate to extract up to 578 mg/g of sorbent at 5 °C under optimal conditions.

Analytica doi: 10.3390/analytica6030027

Authors: Merle Käberich Lisann Nemetz Frank Sacher

Melamine (MEL) has broad applications and can be released to the aquatic environment from various sources, including industry, agriculture, traffic, and household articles. In addition, MEL derivatives ammeline (AMN), ammelide (AMD), and cyanuric acid (CYA) as well as potential precursors cyromazine (CYRO) and hexa(methoxymethyl)melamine (HMMM) are relevant related substances. However, occurrence and transformation in water resources has not yet been thoroughly investigated. Here, we developed a sensitive analytical method for quantification of these analytes by hydrophilic interaction liquid chromatography (HILIC) coupled to tandem mass spectrometry (MS/MS). Direct injection achieved limits of quantification (LOQs) of 0.1 µg/L (AMN 0.2 µg/L; CYA 1 µg/L), while LOQs could be improved to 0.01 µg/L (CYA 0.05 µg/L) by applying evaporation for analyte pre-concentration. The method was extensively validated, showing good recovery, repeatability, and linearity. The evaluation of the matrix effects revealed method applicability for various water matrices, including surface water and wastewater. During proof-of-concept measurements, HMMM in combination with MEL and its derivatives was found in multiple samples, emphasizing the importance of including precursors. In the future, the developed method with its novelty of covering both MEL derivatives and precursors can be applied for comprehensive monitoring programs elucidating MEL sources and transformation in water resources.

Analytica doi: 10.3390/analytica6030026

Authors: Yolisa A. Lucwaba Khakhathi L. Mandiwana

Cement manufacturing is the second largest anthropogenic source of Hg emissions in the environment. Therefore, the establishment of analytical methodologies that can be utilized in the determination of Hg concentration from cement raw materials and cement is of great importance. The total Hg and Hg thermospecies in cement raw materials and cements were determined by thermal desorption techniques with a Zeeman Hg analyzer. No chemical pre-treatment of samples is required for this technique prior to analysis. An optimum single-stage temperature program was applied to determine total Hg at an optimum heating rate of approximately 5 °C s−1 while Hg thermospecies were determined over four stages at an optimum heating rate of approximately 0.2 °C s−1 per stage from ambient temperature to 720 °C. Total mercury concentrations in cement raw materials ranged between 2.19 ng g−1 and 395 ng g−1, while in cement, concentrations ranged between 1.32 ng g−1 and 31.0 ng g−1. The highest Hg contents were found in dust return (580 ng g−1 and 679 ng g−1). Hg thermospecies determination showed that cement raw materials and cements contain one Hg thermospecies that is released at 20–180 °C while dust return contained one to four Hg thermospecies that could be released at 20–180 °C, 180–360 °C, 360–540 °C, and/or 540–720 °C, thus indicating that new Hg compounds are formed during cement production.

Analytica doi: 10.3390/analytica6030025

Authors: Fotouh R. Mansour Marcello Locatelli Alaa Bedair

The Stability Toolkit for the Appraisal of Bio/Pharmaceuticals’ Level of Endurance (STABLE) is introduced and proposed as a comprehensive tool and software to evaluate the stability of active pharmaceutical ingredients (APIs) under various stress conditions. In the pharmaceutical industry, stability testing is a critical step in the drug development process, ensuring the quality, safety, and efficacy of APIs. Traditional stability tests—such as real-time, accelerated, and forced degradation testing—often face challenges, including inconsistent interpretation and implementation across different regions and organizations. STABLE addresses these challenges by providing a standardized and holistic approach to assessing drug stability across five key stress conditions: oxidative, thermal, acid-catalyzed hydrolysis, base-catalyzed hydrolysis, and photostability. Beyond its role as an evaluation tool, STABLE also serves as a practical guide for chemists, encouraging a more complete and thoughtful approach to stability studies. While many investigations focus solely on acid- and base-catalyzed hydrolysis, other critical conditions—such as photostability—are often underexplored or entirely omitted. By highlighting the importance of evaluating all relevant degradation pathways, STABLE promotes more robust and informed stability testing protocols. The index utilizes a color-coded scoring system to quantify and compare stability, facilitating consistent assessments across different APIs. This paper discusses the methodology of STABLE, including the scoring system and specific criteria applied under each condition. This tool is introduced to reflect intrinsic degradation susceptibility under forced conditions. The software is freely available as an open-source tool at bit.ly/STABLE2025, enabling broader accessibility and implementation across the pharmaceutical research community.

Analytica doi: 10.3390/analytica6030024

Authors: Cielo Urquijo Mauricio Maldonado

The dichromate ion (Cr2O72−), a highly toxic chromium VI species, is widely used in industrial processes, generating serious environmental problems when released into water bodies. This investigation proposes the use of a functionalized polymer as an adsorbent material for its removal in the aqueous phase. Poly(butyl methacrylate) (PBMA) was synthesized and modified by impregnation with resorcinarenes derived from long-chain aliphatic aldehydes. To improve the affinity for the dichromate, the resorcinarenes were functionalized with sulfomethyl groups by treatment with Na2SO3. The resulting matrices were characterized using IR-ATR, 1H-NMR, and 13C-NMR, and their adsorbent performance was evaluated via UV-Vis spectroscopy in batch extraction assays. The results showed that the functionalized polymer exhibited a higher adsorption capacity than the base polymer, reaching up to 81.1% removal at pH 5.0 in one hour. These results highlight the potential of PBMA as an effective support and raise a promising research perspective for functionalized resorcinarenes in the development of new materials for the treatment of contaminated water.

Analytica doi: 10.3390/analytica6030023

Authors: Margarita A. Tokareva Evgeny S. Melnikov Elizaveta N. Fisher Tatiana A. Rodina Igor E. Shohin Maria V. Belova

The application of high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) in the analysis of peptide therapeutics demonstrates its capacity to achieve high sensitivity and selectivity, which are essential qualities for the expanding peptide therapeutic industry. Given the challenges posed by hydrophilic peptides in reversed-phase chromatography, we investigated the necessity of a derivatization procedure to improve chromatographic separation and quasimolecular ion fragmentation during MS/MS detection. We investigated how eight different derivatizing agents react with a hydrophilic lysine- and arginine-containing human ezrin peptide-1 (HEP-1) to identify the most suitable one. The results showed that the reaction of HEP-1 with propionic anhydride proceeds most rapidly and completely, providing a high and reproducible yield of the product, which has sufficient retention on the RP column. The 4-propionylated derivative of HEP-1, compared to the other derivatives considered, demonstrates the most pronounced MS/MS fragmentation. The retention time of 2.42 min allows the separation of the substance from the interfering components of the blood plasma matrix and provides a limit of quantification of 5.00 ng/mL, which allows the use of this derivatizing agent for subsequent applications in pharmacokinetic studies, and this approach can improve the analytical parameters of similar peptides in other HPLC-MS/MS studies.

Analytica doi: 10.3390/analytica6030022

Authors: Valvanuz Cahuantzi Rosalba Patiño Herrera Norma Verónica Zavala Alonso Daniela Salado Leza María Selene Berber Mendoza Elías Pérez

This study focuses on the stabilization of a natural hair dye derived from Lawsonia inermis L. (henna) and Indigofera suffruticosa (indigo). Although various formulations already exist, they are designed for immediate use and cannot be stored. Lawsonia, a primary component of the dye, tends to degrade after release. To ensure its stability, freeze-drying was implemented as a protective measure. Colorimetric analysis confirmed the dye’s ability to maintain an intense, uniform coloration even after multiple washing cycles. Stability tests demonstrate that freeze-drying effectively enhances the dye’s stability and capacity to retain its physical properties and color under various environmental conditions, demonstrating its potential for long-term use. The dye’s pH (5.05) aligns with the natural pH of hair, promoting cuticle sealing and improving hair health. Cytotoxicity tests confirmed the dye’s safety, showing no harmful effects. Gray hair exhibited a total color difference (ΔE) of 64.06 after the initial application, using natural gray hair as a reference. By the third application, ΔE increased to 69.86 and gradually decreased to 68.20 after 15 washing cycles, highlighting its long-term durability. Gray hair exposed to 720 h of UV radiation showed a ΔE of 17.34, whereas dyed gray hair exhibited a ΔE of 2.96 compared to non-UV-exposed samples. This indicates superior resistance to color degradation in dyed hair. Also, SEM imaging revealed the dye’s restorative effects, progressively improving hair cuticle structure with each application.

Analytica doi: 10.3390/analytica6020021

Authors: Eliabe Sousa da Silva Jorge Machado Freitas João Pedro Cezário Brandão Ivana Ferreira Simões Alexandre Rafael Lenz Mariana de Paula Drewinski Ágata Carvalho Morais Nelson Menolli Aníbal de Freitas Santos

Edible mushrooms are macroscopic fungi that have been recognized as the “new superfoods” due to their high nutritional and medicinal values. The aim of this study was to develop and optimize a method for the wet digestion of edible mushrooms using a closed digestion block for the determination of macro- and micronutrients (Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, and Zn) using microwave-induced plasma emission spectrometry (MIP OES). For the digestion of the samples, a 23 factorial design was used to evaluate the amount of HNO3 65% (m m−1), H2O2 30% (m m−1) and the digestion time, in 500 mg of the sample (dry and crushed) at 200° C. The method was applied to eleven species of edible or medicinal mushrooms (edible cultivated from wild strains, wild edible, and commercials medicinal). The average concentrations (in mg kg−1) showed higher levels of K (1442.85–17,534.97), Mg (1295.40–13,550.72), Fe (11.33–27.38), Zn (28.86–36.09), and Mn (10.22–10.97). This study contributed to the determination of the multi-element composition and nutritional potential of edible mushrooms from Brazil.

Analytica doi: 10.3390/analytica6020020

Authors: Daniel Hernández-Ramírez Carlos Ríos-Martínez José Luis Pinedo-Vega Fernando Mireles-García Fernando De la Torre Aguilar Edmundo Escareño-Juárez

This study investigated the spatial distribution and radiological risks of naturally occurring radionuclides (226Ra, 232Th, 40K) in 37 soil samples from Zacatecas, located in north-central Mexico, using high-resolution gamma spectrometry. Results revealed 40K concentrations (mean: 736.81 Bq kg−1), nearly double the global average, while 226Ra (29.96 Bq kg−1) and 232Th (29.72 Bq kg−1) aligned with worldwide norms. Geoaccumulation indices identified moderate 40K accumulation at 22 sites, with El Capulín classified as moderately contaminated (Igeo = 1.07). Radiological risk indices showed absorbed dose rates (62.52 nGy h−1) and excess lifetime cancer risk (0.330 × 10−3) exceeding global thresholds by 4% and 14%, respectively. Multivariate analyses demonstrated strong Spearman correlations (ρ = 0.75–1.00) among risk indices, while spatial interpolation identified southern/western regions as high-risk zones. These findings emphasize the necessity of integrating spatial analysis with multivariate statistical techniques in environmental radioprotection frameworks. While most of the study area complies with international safety standards, the identified zones exceeding dose thresholds warrant prioritized management to mitigate potential cumulative health risks.

Analytica doi: 10.3390/analytica6020019

Authors: Antonella Maria Aresta Giovanna Mancini Nicoletta De Vietro Carlo Zambonin

A solid phase microextraction (SPME) method coupled with liquid chromatography (LC) and fluorescence/ultraviolet-diode array detection was developed for the simultaneous determination of quercetin and trans-resveratrol. The chromatographic, detection, and SPME extraction/desorption conditions were systematically optimized. The performance of four commercial SPME fibers—polyacrylate (PA), polyethylene glycol (PEG), polydimethylsiloxane (PDMS), and polydimethylsiloxane-divinylbenzene (PDMS-DVB)—was evaluated and compared with a homemade polydopamine (PDA)-coated fiber. While all of the fibers successfully extracted the target analytes, their efficiencies varied significantly. The PA, PEG, and PDA fibers demonstrated superior performance, exhibiting wide linearity ranges (0.03–1 µg/mL (PA and PEG) and 0.06–1 µg/mL (PDA) for quercetin, 0.01–1 µg/mL for trans-resveratrol); high sensitivity (LODs of 0.01 µg/mL (PA and PEG) and 0.02 µg/mL (PDA) for quercetin, 0.003 µg/mL for trans-resveratrol); and excellent precision. Among these, the polyacrylate coating delivered the best analytical performance and was selected for further application. The optimized method was applied to analyze winemaking by-products (seeds, skins, and stalks) using SPME on ethanol-macerated extracts subjected to brief ultrasonication. Quercetin and trans-resveratrol were quantified in pomace extracts at concentrations of 104.3 ± 8.2 µg/g and 38.5 ± 4.1 µg/g, respectively. Recovery experiments confirmed the method’s accuracy, with recoveries of 99.1 ± 7.4% for quercetin and 98.5 ± 9.8% for trans-resveratrol. This study establishes a reliable, sensitive, and efficient approach for the determination of these bioactive compounds in complex matrices, with potential applications in the food and pharmaceutical industries.

Analytica doi: 10.3390/analytica6020018

Authors: Sophia R. Ginet Frank Gonzalez Maxine L. Marano Megha D. Salecha Joseph E. Reiner Gregory A. Caputo

Early detection of cancer can dramatically improve long-term prognosis and survivability in a variety of different cancer types. However, for many cancer types, the ability to effectively detect early-developing tumors is challenging, especially in physiological locations with limited visibility or access. Previously, we reported a sensing platform and methodology to detect biomarker peptides found in urine from ovarian cancer patients. This sensing platform relies on peptide interactions with gold nanoclusters through thiol-mediated linkages; thus, the sensitivity of the biomarker assay is directly related to appropriate redox states of the biomarkers in question. Here, we report on an expansion of the traditional thiol-reactivity assay originally developed by Ellman to include and evaluate a variety of solution modifications that may be used in conjunction with the biomarker-sensing platform. Because biomarker peptides may be isolated from a variety of biological tissues or fluids, depending on the target condition or disease, we screened numerous solution conditions that may be directly used in sample preparation and peptide extraction. The data demonstrate that the assay maintains linearity under these various conditions. The assay was then applied to a variety of models and biomarker peptides and exhibits the expected linear response. These results demonstrate the applicability of the thiol-reactivity assay to biologically derived samples, and the flexibility to ensure sample preparation and treatment will retain the appropriate sample redox conditions to ensure optimal interactions with the biosensor platform. It also facilitates the ability to perform quality control on clinically derived biological samples to ensure appropriate preparations, and concentrations are available for application to the nanopore biosensor platform.

Analytica doi: 10.3390/analytica6020017

Authors: Enrico Greco

Over the past decade, more than a thousand new psychoactive substances (NPSs) have emerged worldwide. This rapid proliferation of “designer drugs” poses significant challenges for drug control, forensic analysis, and public health. Artificial intelligence (AI) has increasingly been applied to address these challenges in NPS design and analysis. This review provides a comprehensive overview of AI methodologies—including deep learning, generative models, and quantitative structure–activity relationship (QSAR) modeling—and their applications in the synthesis, prediction, and identification of NPSs. We discuss how AI-driven generative models have been used to design novel psychoactive compounds and predict their pharmacological activity, how QSAR models can forecast potency and toxicological profiles, and how machine learning is enhancing analytical chemistry workflows for NPS identification. Special emphasis is placed on mass spectrometry (MS)-based techniques, where AI algorithms (e.g., for spectral prediction and pattern recognition) are revolutionizing the detection and characterization of unknown NPSs. A dedicated section examines the legal and regulatory implications of AI-generated psychoactive substances in the European Union (EU) and United States (USA), highlighting current policies, potential gaps, and the need for proactive regulatory responses. The review concludes with a discussion of the benefits and limitations of AI in this domain and outlines future directions for research at the intersection of AI, analytical chemistry, and drug policy.

Analytica doi: 10.3390/analytica6020016

Authors: Nassima Boutaoui Meryem Acila Nesrine Lariche Redouane Lemoui Asma Khellafi Cristina Campestre Francesco Melfi Marcello Locatelli

The objective of this work is to study the anti-inflammatory effect in vitro and in vivo of microwave (MW) extracts of Thymus algeriensis. The in vitro study was performed by the human red blood cell protection test, while the in vivo study used the carrageenan-induced rat paw edema model. The experimental results were confirmed by a molecular docking calculation. The results indicated that all the microwave extracts have a moderate anti-inflammatory effect, depending on their richness in phenolic compounds. Among the extracts studied, the one obtained at 100 °C for 15 min exhibited the most pronounced anti-inflammatory effect, with an inhibition of 78.52%, which is attributed to its high flavonoid content. In particular, the flavonoids naringin and catechin showed the best affinity for the target protein, with values of −10.3 kcal/mol and −9.2 kcal/mol, respectively, as well as low inhibition constants of 0.028 μM and 0.18 μM. These results indicate that these flavonoids generate interactions that enhance the stability of the target ligand–protein complex, thus contributing to the observed anti-inflammatory effect.

Analytica doi: 10.3390/analytica6020015

Authors: Sayed M. Saleh Shahad Altaiyah Reham Ali

This research introduces a novel synthetic method for introducing highly luminescent silver nanoclusters (AgNCs). The technique relies on coffee Arabica seed extraction (CSE), which is the focus of this study. Our developed and manufactured ecologically friendly approach has enhanced the selectivity of AgNCs for Hg(II) ions. The coffee extract was employed in the synthesis process to stabilize and enhance the quantity of AgNCs generated. Various advanced techniques were used to characterize the AgNCs precisely in their prepared condition concerning size, surface modification, and composition. The fluorescence quenching of the AgNCs was the mechanism via which the CSE-AgNCs reacted to the principal metal ions in the experiment. Using this sensing methodology, a very accurate and selective sensing method is provided for Hg(II) in the dynamic range of 0.117 µM to 1.4 µM, with a limit of detection (LOD) equal to 35.21 nM. Comparative research was conducted to determine how selective CSE-AgNCs are for Hg(II) ions compared to other ions. Consequently, a notable degree of selectivity of AgNCs towards these Hg(II) metal ions was achieved, allowing the sensitive detection of Hg(II) metal ions, even their interfering metal ions, in the environment. AgNCs can detect Hg(II) at acceptable values within the nanomolar range. Based on their characteristics, Hg(II) ions were detected in real samples using CSE-AgNCs.

Analytica doi: 10.3390/analytica6020014

Authors: Ivana Vrca Dora Jukić Josip Radić Ivana Anđelić

Tropaeolum majus L. is an edible plant known for its therapeutic and medicinal effects, as it possesses bioactive compounds (polyphenols, glucosinolates, fatty acids) and has various biological activities, which makes it interesting and makes it the research objective of this work. The aim of this study was to extract the phenolic compounds present in the T. majus plant by maceration and ultrasound-assisted extraction techniques using two solvents: 80% ethanol and water. In vitro digestion was performed to see how stable the phenolic components are after digestion. An LC-MS/MS instrument was used to identify and quantify the phenolic components. The highest extraction yield for the T. majus extract was obtained when 80% ethanol was used as the solvent after ultrasound-assisted extraction (32.63 ± 2.28 mg/0.5 g fresh material), while the opposite was true for the T. majus extract when water was used as the solvent and maceration as the technique (21.00 ± 3.26 mg/0.5 g fresh material). However, water extracted more phenolic components for identification. In general, the major compounds before in vitro digestion with commercial enzymes and with 80% ethanol and water as the solvents were p-hydroxybenzoic acid, protocatechuic acid, p-coumaric acid, caffeic acid and chlorogenic acid. After in vitro digestion using both solvents and extraction procedures, the stable phenolic compounds were p-hydroxybenzoic acid (>67%) and p-coumaric acid (>35%). Caffeic acid and quinic acid were not detected after digestion. The stability of certain phenolic components could influence the use of such extracts as dietary supplements with beneficial effects on human health, making them interesting for the general population.

Analytica doi: 10.3390/analytica6020013

Authors: Miao Fan Huinan Yang Jun Chen

With the rise in global temperatures, it is of great significance to achieve rapid and accurate detection of greenhouse gases, such as carbon dioxide and methane. Raman spectroscopy not only overcomes the weakness of absorption spectroscopy in simultaneously measuring homonuclear diatomic molecules but also enables the simultaneous detection of multiple gases using a single-wavelength laser. However, due to the small Raman scattering cross-section and weak intensity of molecules, its application in gas detection is limited. To enhance the intensity of Raman scattering, this paper designs and constructs a multi-pass enhanced Raman spectroscopy setup. This study focuses on the effects of Raman scattering collection geometry, laser multi-pass patterns, and laser polarization relative to the Raman collection direction on signal intensity. Investigations into Raman scattering collection angles of 30°, 60°, and 90° reveal that the Raman scattering signal intensity increases as the collection angle decreases. Different laser multi-pass patterns also impact the signal, with the near-concentric linear multi-pass pattern found to collect more signals. To minimize the influence of excitation light on the signal, a side collection system is employed. Experiments show that the Raman scattering signal is stronger when the laser polarization is perpendicular to the collection direction. This study achieves overall system performance enhancement through coordinated optimization of multiple physical mechanisms, including Raman scattering collection geometry, laser multi-pass patterns, and laser polarization characteristics. The optimized setup was employed to characterize the laser power dependence for nitrogen, oxygen, and carbon dioxide detection. The results showed that the Raman scattering intensity varied linearly with the laser power of the gases, with linear fitting goodness R2 values of 0.9902, 0.9848, and 0.9969, respectively. Finally, by configuring different concentrations of carbon dioxide gas using nitrogen, it was found that the Raman scattering intensity varied linearly with the concentration of carbon dioxide, with a linear fitting goodness R2 of 0.9812. The system achieves a CO2 detection limit of 500 ppm at 200 s integration time, meeting the requirements for greenhouse gas emission monitoring applications.

Analytica doi: 10.3390/analytica6020012

Authors: Ram Kumar Sushant Salwan Pawan Kumar Nisha Bansal Bhupinder Kumar

Electroanalysis has emerged as a critical tool in the pharmaceutical industry, offering versatile and sensitive methods for drug analysis. This review explores the principles, techniques, and applications of electroanalysis in pharmaceuticals, emphasizing its role in drug development, quality assurance, pharmacokinetics, and environmental monitoring. Key electroanalytical methods, including voltammetry, potentiometry, and amperometry, are detailed along with their practical applications, such as detecting active pharmaceutical ingredients, monitoring drug metabolites, and ensuring product stability. Innovations in electrode materials and biosensors have enhanced their sensitivity and specificity, paving the way for advanced drug screening and therapeutic monitoring. Challenges like electrode fouling, selectivity issues, and regulatory constraints are discussed, along with strategies to overcome them. Future trends highlight the integration of nanotechnology, AI, and portable sensors to facilitate real-time analysis and personalized medicine. These advancements position electroanalysis as an indispensable component of modern pharmaceutical research and healthcare. Future perspectives emphasize the integration of nanotechnology and artificial intelligence (AI) to optimize experimental processes and data interpretation. This study also predicts the increased adoption of lab-on-a-chip systems and bioelectrochemical sensors to meet the growing demand for precision medicine and sustainable pharmaceutical practices. These advancements position electroanalysis as a cornerstone of pharmaceutical research, paving the way for more efficient drug development, improved patient outcomes and better environmental management. This comprehensive review underscores the transformative potential of electroanalysis in addressing the evolving challenges of the pharmaceutical industry and provides a foundation for future innovations. This review does not explicitly define the timeframe for the considered advancements. However, it discusses recent technological developments, including innovations in nanostructured electrodes, microfluidic integration, and AI-driven data analysis, indicating a focus on advancements primarily from the last few years, i.e., from 2020 to 2025.

Analytica doi: 10.3390/analytica6010011

Authors: Mauro Castrucci Mauro Tomassetti Emanuele Dell’Aglio Giovanni Visco Maria Pia Sammartino Marco Castracane

A diagnostic chemical analysis has been performed on a Roman Cippus funebris in precious white marble located close to an ancient Roman road. The Cippus was in good condition but almost completely covered by a black patina, requiring a conservative cleaning intervention. The restorer in charge of the restoration asked us to make a preliminary diagnosis, on the basis of which we could suggest the most appropriate intervention. The Cippus was dedicated to the young Quintus Cornelius Proclianus, who died at the age of 15, by his mother Valeria Calpurnia Scopele. It perfectly fits into the Roman funerary liturgy and also shows an Etruscan-type iconography that seems to confirm the Etruscan Gens of the family and its dating to the 1st century AD. Ion chromatography (IC) analyses were performed to determine anions and cations on solutions obtained from the extraction of salts from the four samples of the Cippus. pH, conductivity, and red-ox potential measures, as well as UV-visible spectra were carried out on the same solutions. A small fragment, spontaneously fallen from the Cippus’ surface, was also observed by optical microscopy (OM) and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS). From the analyses, the dark patina that covered the surface before cleaning turned out to be made of black crusts, that is, smog particles adsorbed on sulfates, but above all, by a layer of microflora. The results allowed us to suggest some conservative interventions.

Analytica doi: 10.3390/analytica6010010

Authors: Anil Kumar Meher Akli Zarouri

Green analytical chemistry represents a transformative approach to analytical science, emphasizing sustainability and environmental stewardship while maintaining high standards of accuracy and precision. This review highlights recent innovations in green analytical chemistry, including the use of green solvents, such as water, supercritical carbon dioxide, ionic liquids, and bio-based alternatives, as well as energy-efficient techniques like microwave-assisted, ultrasound-assisted, and photo-induced processes. Advances in green instrumentation, including miniaturized and portable devices, and the integration of automation and chemometric tools, have further enhanced efficiency and reduced the environmental footprint of analytical workflows. Despite these advancements, challenges remain, including the need to balance analytical performance with eco-friendliness and the lack of global standards to measure and promote sustainable practices consistently. However, the future of green analytical chemistry looks promising, with emerging technologies like artificial intelligence and digital tools offering new ways to optimize workflows, minimize waste, and streamline analytical processes. By focusing on these areas, green analytical chemistry is transforming analytical methodologies into tools that not only achieve high performance but also align with global sustainability goals. This review underscores how green analytical chemistry is more than just a scientific discipline, but a pathway for reducing the ecological impact of analytical processes while driving innovation in science and industry. With the continued commitment to research, collaboration, and the adoption of cutting-edge technologies, green analytical chemistry has the potential to shape a greener and more sustainable future for analytical chemistry and its diverse applications.

Analytica doi: 10.3390/analytica6010009

Authors: Thiago Gabry Barbosa Daniela Nunes da Silva Marcella Matos Cordeiro Borges Scarlat Ohanna Dávila da Trindade Thaís Cristina de Oliveira Cândido Arnaldo César Pereira

This study investigated the effect of surface treatments on the electrochemical performance of 3D-printed electrodes for versatile applications. The conductive filament was obtained from a mixture of polylactic acid (PLA) and carbon black (CB) at a 7:3 ratio (PLA/CB) dispersed in acetic acid and dichloroethane (3:1) medium. The treatments used were HNO3, NaOH, DMF (immersion for 30, 30, and 15 min, respectively), and electrochemical activation (amperometry 150 s, 1.8 V). In general, the treatments allow greater exposure of the conductive material and active sites present on the sensor surface. This was confirmed using cyclic voltammetry and electrochemical impedance spectroscopy. The analyses were conducted with a 0.10 M KCl solution containing the redox pair ferricyanide/ferrocyanide 5.00 mmol L−1. Based on the results obtained, the electroactive area, kinetic constant and resistance to electron transfer were determined for each treatment. The treatment in basic medium stood out as the treatment that was most appropriate for the device used in this work. The device was also tested for its potential in the analysis of acetaminophen, demonstrating satisfactory results permitting the application of 3D-SBasic in the analysis of acetaminophen.

Analytica doi: 10.3390/analytica6010008

Authors: Adrián Fuente-Ballesteros Ana Jano Ana M. Ares Silvia Valverde José Bernal

GLANCE (Graphical Layout Tool for Analytical Chemistry Evaluation) is an innovative and adaptable free, editable template specifically designed to help researchers visually summarize their analytical chemistry methods in a structured and clear manner. It provides an accessible solution to the challenge of presenting complex scientific data, offering a significant advantage over traditional reporting methods, which often lack visual clarity. This is crucial because no previous tool has been developed to summarize analytical methods in such a comprehensive and concise visual format, significantly enhancing the process of gathering and presenting key information, particularly in review articles. The GLANCE template (bit.ly/409cwDd) is composed of twelve distinct attributes, each targeting critical aspects of method development (novelty, analytes, sample preparation, reagents, instrumentation, method validation, matrix effects and recoveries, application to real samples, analytical metrics, main results, limitations, and additional information). By filling out each block with keywords or short phrases, authors can provide a concise yet thorough overview of their method. Once completed, the template can be easily downloaded and included in scientific articles. This straightforward integration enhances both the clarity and accessibility of publications, providing the scientific community with a quick snapshot of the principal features of research.

Analytica doi: 10.3390/analytica6010007

Authors: Jaehyun Park Ki Hyun Nam

Serial femtosecond crystallography (SFX) using X-ray free-electron lasers (XFELs) enables the determination of biological and chemical structures without radiation damage. In SFX experiments, a sample delivery system is essential for delivering numerous crystals to the X-ray interaction point in a serial and stable manner. Among the various sample delivery methods, the fixed-target (FT) sample delivery system is straightforward and widely used for collecting SFX data due to its advantages of low sample consumption and reduced physical damage to crystals during data collection. Here, we review the development of the FT sample delivery system for SFX with the Pohang Accelerator Laboratory X-ray free-electron laser (PAL-XFEL). The specifications and operational conditions of the FT-SFX sample chamber are described. The design, specifications, and applications of the one- and two-dimensional FT sample holders developed for SFX with the PAL-XFEL are also detailed. Furthermore, the applications of each FT sample delivery system are discussed. This review not only provides valuable information on the FT system used in SFX experiments with the PAL-XFEL but also offers insights into the development of FT sample delivery systems.

Analytica doi: 10.3390/analytica6010006

Authors: Amin Fatoni Mekar Dwi Anggraeni Eni Rahmawati

Neonatal jaundice affects over 80% of newborns globally, posing significant health risks if untreated. Current diagnostic methods either lack accuracy or are prohibitively expensive, limiting accessibility in low-resource settings. This study presents a cost-effective, wearable device for non-invasive bilirubin monitoring based on forehead skin tone analysis. The device, comprising a TCS34725 color sensor and ESP32-C3 microcontroller, offers real-time bilirubin predictions validated against standard clinical methods. Calibration ensures reproducibility across devices, with recovery rates of 91–107%, meeting analytical validation standards. This innovation has the potential to revolutionize neonatal care by providing accessible, sustainable, and accurate monitoring, especially in underserved regions.

Analytica doi: 10.3390/analytica6010005

Authors: Ki Hyun Nam

Serial crystallography (SX) determines the crystal structures of target molecules at room temperature with minimal radiation damage. During SX data collection, the stable delivery of many microcrystals to the X-ray interaction point is crucial for efficient sample consumption and effective beamtime usage. Most microcrystal delivery techniques for SX require sophisticated devices or specialized techniques, which can be challenging for data collection. This review introduces a straightforward method that delivers microcrystal samples in SX experiments using a commercially available syringe and syringe pump. This method does not require specialized skills for sample delivery and can be tested in the laboratory prior to SX data collection at the beamline. Advantages and disadvantages of this method are also discussed, along with various application cases. This straightforward sample delivery approach is concluded to facilitate efficient SX data collection.

Analytica doi: 10.3390/analytica6010004

Authors: Chiravoot Pechyen Calin Trif Benya Cherdhirunkorn Surachet Toommee Yardnapar Parcharoen

In recent years, Thailand’s agriculture sector has seen a significant rise in pesticide usage due to its vital role in the economy and global food trade. However, the uncontrolled use of pesticides poses severe health and environmental risks. This research focuses on the detection of pesticide residues, particularly carbaryl and paraoxon-ethyl, which are prevalent due to their high efficacy in pest control but pose neurological health risks by inhibiting acetylcholinesterase (AChE) activity, potentially impacting human health. The developed method assesses pesticide concentration by measuring changes in the CIE-LAB color space using a smartphone camera. Testing several concentrations (0.2, 0.6, and 1.0 ppm) over time revealed significant differences via ANOVA (F = 32.8, p < 0.001) and a strong linear relationship with R2 values from 0.9129 to 0.9973 through regression analysis. Additionally, principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were utilized to further understand the relationship between color changes and pesticide type and concentration. PCA showed that the L* and b* values contributed most to explaining the variance in the data (96.24%), while PLS-DA provided classification models. These strong linear relationships between pesticide concentration and colorimetric changes showcase the method’s accuracy and potential for on-site pesticide monitoring in agricultural produce, emphasizing technological advancements in sustainable agriculture practices. This research presents encouraging findings from an inexpensive and straightforward method for detecting pesticide residues, suggesting that a specialized mobile application could enhance the implementation of the proposed system.

Analytica doi: 10.3390/analytica6010003

Authors: Victor Alexandre Ribeiro Leite Sthephane Pereira de Oliveira Larissa Cristina de Souza Léa Júlia de Paula Silva Laís Fonseca Silva Thaís Cristina de Oliveira Cândido Daniela Nunes da Silva Arnaldo César Pereira

The development of screen-printed electrochemical sensors represents a rapidly expanding research field with great potential for applications in the rapid and sensitive determination of drugs in complex matrices. This work presents a review of the state-of-the-art examples of this technology, focusing on its application in real matrices such as water, pharmaceutical formulations, and biological fluids. We discuss the main materials used in developing conductive inks, highlighting their properties and influence on sensor performance. The characterization of materials and sensors is crucial to ensure the reproducibility and reliability of results. Additionally, we address the challenges associated with the application of these sensors in complex matrices, such as interferences from other components and the need for sample pretreatment. Finally, we present future perspectives for developing screen-printed electrochemical sensors, with an emphasis on new technologies and materials that can improve the sensitivity, selectivity, and stability of these devices.

Analytica doi: 10.3390/analytica6010002

Authors: Usha Sabharwal Piyush Kant Rai Kamlesh Choure R. B. Subramanian Jeong Chan Joo Ashutosh Pandey

The role of pipecolic acid (Pip) in plant immune responses, particularly against bacterial wilt pathogens, is significant. This research aimed to understand the interaction between plant defense-responsive enzymes and Pip by analyzing methanolic extracts from different treatments of tolerant (GAT5) and susceptible (GT2) tomato cultivars. LC-MS analysis demonstrated that the foliar application of Pip significantly influenced tomato metabolites, especially in bacterial wilt-infected plants, with a more pronounced effect in tolerant varieties. Principal component analysis (PCA) revealed that Pip-treated plants of tolerant varieties exhibited better coordinated metabolome profiles than those of susceptible varieties. Notable variations were observed in the levels of specialized metabolites, such as salicylic acid (SA), N-hydroxy pipecolic acid (NHP), and Pip, which are essential for producing defense compounds. Molecular docking studies further explored Pip’s interactions with key plant enzymes involved in defense mechanisms and showed that Pip acts as an effective organic inducer of systemic acquired resistance (SAR). These findings highlight Pip’s potential as a natural agent for enhancing plant tolerance to pathogens, offering promising implications for agricultural practices and improving crop resilience against diseases. This study enhances our understanding of Pip’s role in plant defense and provides a foundation for developing Pip-based strategies for sustainable agriculture.

Analytica doi: 10.3390/analytica6010001

Authors: Juan Hidalgo Luis Hidalgo Carlos Serrano Diego Punina Erik Rea Marlon Ilbay Javier E. Vilasó-Cadre Ivan A. Reyes-Domínguez

Corrosion is a critical industrial problem. To solve this problem, the present research analyzed the influence of corrosive media on the efficiency of a guayusa inhibitor. Therefore, guayusa extract was obtained, and five groups of ASTMS A36 steel test tubes were prepared, each with variable extract concentrations (200 ppm, 400 ppm, 600 ppm, 800 ppm, and 1000 ppm) that were exposed to different corrosive media (5% NaCl, 5% NaCl + acetic acid, 1% HNO3, and 10% HNO3). The results obtained were compared to determine the percentage efficiency of the inhibitor in each of the corrosive media. This study provides a detailed understanding of how the corrosive environment influences the effectiveness of a guayusa inhibitor, which is used as a green inhibitor for the first time, allowing its viability and performance to be assessed under various conditions.

Analytica doi: 10.3390/analytica5040043

Authors: Anastasia Yu. Sholokhova Svetlana A. Borovikova Dmitriy D. Matyushin

Substituted phenols, including chlorophenols, are important analytes, particularly in the context of environmental analysis. Chlorophenols are formed during the disinfection of drinking water by chlorination and are important water pollutants. Gas chromatography–mass spectrometry (GC-MS) is an important method for the analysis of chlorophenols. Retention indices are used in GC-MS analysis to improve the accuracy of identification. Our research reveals that the retention indices currently available for substituted phenols are erroneous in a number of cases. We report reliable retention index values for pentafluorophenol, 5-methoxy-2-nitrophenol, 4-cyanophenol (stationary phase: 5%-phenyl-polymethylsiloxane), 3-methoxyphenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,3-dichlorophenol, 2,5-dichlorophenol, 2,6-dichlorophenol, 3,4-dichlorophenol, 3,5-dichlorophenol, 2,3,5-trichlorophenol, 2,3,6-trichlorophenol, 2,4,5-trichlorophenol, and 2,4,6-trichlorophenol (stationary phase: polyethylene glycol modified with 2-nitroterephthalic acid). The structures of the standard samples were confirmed, and measurements were performed under various conditions. The analysis of the causes of the incorrect records appearing in the well-known NIST database was also carried out.

Analytica doi: 10.3390/analytica5040042

Authors: Tamara Quesada-Soto Luis Felipe Vargas-Huertas José Roberto Vega-Baudrit Mirtha Navarro-Hoyos Andrea Mariela Araya-Sibaja

Saquinavir is a drug used as an HIV treatment, with recent reports of new uses. It has poor aqueous solubility and very low oral bioavailability. However, when prepared in a eutectic mixture with the natural bioenhancer, piperine, it demonstrated improvements in these drawbacks. Therefore, considering that EMs can be easily produced and scaled-up, it could potentially be used in new pharmaceutical formulations. For this purpose, an analytical method capable of quantifying SQV in the presence of PIP is required for quality control purposes. In this context, UV–Vis equipment is simpler to use and cheaper than HPLC, and it is commonly available in most laboratories. Therefore, a derivative spectrophotometry method at 245 nm was developed and validated to quantify SQV. The method showed good linearity from 0.5 to 100.0 mg/L, with a limit of detection and limit of quantification of 0.331 mg/L and 0.468 mg/L, respectively. Furthermore, it was precise, accurate, and demonstrated good specificity up to a 1:4.3 SQV:PIP ratio. Consequently, the results demonstrate that the method can be employed for SQV quantification in the presence of PIP as an economical and simple technique. This contribution could be the basis for a quality control technique for these types of products.

Analytica doi: 10.3390/analytica5040041

Authors: Eugene B. Postnikov Alexander V. Sychev Anastasia I. Lavrova

We report a workflow and a software description for digital image colorimetry aimed at obtaining a quantitative dose–response curve and the minimal inhibitory concentration in the Resazurin Microtiter Assay (REMA) test of the activity of antimycobacterial drugs. The principle of this analysis is based on the newly established correspondence between the intensity of the a* channel of the CIE L*a*b* colour space and the concentration of resorufin produced in the course of this test. The whole procedure can be carried out using free software. It has sufficiently mild requirements for the quality of colour images, which can be taken by a typical smartphone camera. Thus, the approach does not impose additional costs on the medical examination points and is widely accessible. Its efficiency is verified by applying it to the case of two representatives of substituted 2-(quinolin-4-yl) imidazolines. The direct comparison with the data on the indicator’s fluorescence obtained using a commercial microplate reader argues that the proposed approach provides results of the same range of accuracy on the quantitative level. As a result, it would be possible to apply the strategy not only for new low-cost studies but also for expanding databases on drug candidates by quantitatively reprocessing existing data, which were earlier documented by images of microplates but analysed only qualitatively.

Analytica doi: 10.3390/analytica5040040

Authors: Azizah Alamro Thanih Balbaied

Boron nitride nanostructures (BNNs), including nanotubes, nanosheets, and nanoribbons, are renowned for their exceptional thermal stability, chemical inertness, mechanical strength, and high surface area, making them suitable for advanced material applications. Metal–organic frameworks (MOFs), characterized by their porous crystalline structures, high surface area, and tunable porosity, have emerged as excellent candidates for gas adsorption and storage applications, particularly in the context of hydrogen. This paper explores the synthesis and properties of BNNs and MOFs, alongside the innovative approach of integrating BNNs within MOFs to create composite materials with synergistic properties. The integration of BNNs into MOFs enhances the overall thermal and chemical stability of the composite while improving hydrogen sensing and storage performance. Various synthesis methods for both BNNs and MOFs are discussed, including chemical vapor deposition, solvothermal synthesis, and in situ growth, with a focus on their scalability and reproducibility. Furthermore, the mechanisms underlying hydrogen sensing and storage are examined, including physisorption, chemisorption, charge transfer, and work function modulation. Electrochemical characterization techniques, such as cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge–discharge, are used to analyze the performance of BNN-MOF systems in hydrogen storage and sensing applications. These methods offer insights into the material’s electrochemical behavior and its potential to store hydrogen efficiently. Potential industrial applications of BNN-MOF composites are highlighted, particularly in fuel cells, hydrogen-powered vehicles, safety monitoring in hydrogen production and distribution networks, and energy storage devices. The integration of these materials can contribute significantly to the development of more efficient hydrogen energy systems. Finally, this study outlines key recommendations for future research, which include optimizing synthesis techniques, improving the hydrogen interaction mechanisms, enhancing the stability and durability of BNN-MOF composites, and performing comprehensive economic and environmental assessments. BNN-MOF composites represent a promising direction in the advancement of hydrogen sensing and storage technologies, offering significant potential to support the transition toward sustainable energy systems and hydrogen-based economies.

Analytica doi: 10.3390/analytica5040039

Authors: Gül Keklik Şah Aybüke A. Isbir Turan

This study describes the development of an optical-based surface plasmon resonance (SPR) aptasensor for the detection of cocaine. The aptasensor was prepared by first attaching gold nanoparticles to a clean SPR chip surface, followed by the addition of an aptamer to create a modified surface. This surface was characterized using contact angle and atomic force microscopy, revealing surface roughness values of 0.28 nm and 28.12 nm for the blank and modified surfaces, respectively. The detection of cocaine was carried out in the concentration range of 1 ng/mL to 1000 ng/mL, with a detection time of approximately 8 min and a cocaine limit of detection (LOD) of 0.43 ng/mL. Repeatability studies were conducted, and the stability of the signal response was examined at a concentration of 200 ng/mL. Adsorption isotherm models, including Scatchard, Langmuir, and Freundlich models, were calculated to assess the surface homogeneity of the SPR aptasensor chip, with the results indicating compatibility with the Langmuir isotherm model.

Analytica doi: 10.3390/analytica5040038

Authors: José Luis Casas-Hinestroza Adrián Pérez-Redondo Mauricio Maldonado

Complexation between carnitine and acetylated or benzylated pyrogallol[4]arenes was studied in DMSO via dynamic NMR, UV-vis spectroscopy, and in the gas phase via electrospray ionization-mass spectrometry (ESI-MS). In the presence of benzylated tetra(phenyl)pyrogallol[4]arene, the interaction with carnitine via NMR was evident and was confirmed by means of UV-vis spectroscopy, where the formation of a host–guest-type complex was observed; this was stable and exhibited a change to a clear color. With benzylated tetra(propyl)pyrogallol[4]arene, the results showed that there was no interaction with the neurotransmitter. A plausible explanation for this behavior is based on the dynamic behavior of the benzylated tetra(propyl)pyrogallol[4]arene, and this shows the dependence on the size of the cavities and the substituent on the lower rim of the pyrogallo[4]arenes. Suitable crystals of O-acetylated-tetra(propyl)calix[4]pyrogallolarene were obtained and were characterized through an X-ray crystal structure determination.

Analytica doi: 10.3390/analytica5040037

Authors: Thaís Cristina de Oliveira Cândido Daniela Nunes da Silva Marcella Matos Cordeiro Borges Thiago Gabry Barbosa Scarlat Ohanna Dávila da Trindade Arnaldo César Pereira

Three-dimensional printing technology has emerged as a versatile and cost-effective alternative for the fabrication of electrochemical sensors. To enhance sensor sensitivity and biocompatibility, a diverse range of biocompatible and conductive materials can be employed in these devices. This allows these sensors to be modified to detect a wide range of analytes in various fields. 3D-printed electrochemical sensors have the potential to play a pivotal role in personalized medicine by enabling the real-time monitoring of metabolite and biomarker levels. These data can be used to personalize treatment strategies and optimize patient outcomes. The portability and low-cost nature of 3D-printed electrochemical sensors make them suitable for point-of-care (POC) diagnostics. These tests enable rapid and decentralized analyses, aiding in diagnosis and treatment decisions in resource-limited settings. Among the techniques widely reported in the literature for 3D printing, the fused deposition modeling (FDM) technique is the most commonly used for the development of electrochemical devices due to the easy accessibility of equipment and materials. Focusing on the FDM technique, this review explores the critical factors influencing the fabrication of electrochemical sensors and discusses potential applications in clinical analysis, while acknowledging the challenges that need to be overcome for its effective adoption.

Analytica doi: 10.3390/analytica5040036

Authors: Christopher L. Harmon Sean Butts Mary Elizabeth Sowers Ed Bethea David Jenkins

The GPHF-Minilab™ is a portable toolkit for performing qualitative methods such as thin-layer chromatography (TLC) on common pharmaceuticals. It is particularly useful in resource-limited locations where it is more challenging to monitor for substandard and falsified (SF) medicines. However, the GPHF-Minilab™ TLC methods are only semi-quantitative at best and thus have issues monitoring product quality effectively. We have improved on the GPHF-Minilab™ TLC method for metronidazole, a common antibiotic, by making it fully quantitative. Sample solutions were spotted on TLC plates alongside three metronidazole standards at different concentrations. After development, plates were imaged in a lightbox with two different smartphone cameras. Images were processed through the open-source program ImageJ and resulting pixel data from the standard spots were used to create a calibration curve, enabling quantitation of the sample. The USP Metronidazole Tablet high-performance liquid chromatography (HPLC) assay was used as the reference method. We validated this TLC method using 250 and 500 mg metronidazole tablets from different manufacturers and assessed linearity, range, accuracy, precision, intermediate precision, specificity, and robustness. These improvements should enhance the GPHF-Minilab™ TLC methods for metronidazole product screening. Additionally, the procedure is extensible to other analytes, although further validation would be required for each Minilab method.

Analytica doi: 10.3390/analytica5040035

Authors: Gabriela Elizabeth Quintanilla-Villanueva Araceli Sánchez-Álvarez Raisa Estefanía Núñez-Salas Melissa Marlene Rodríguez-Delgado Donato Luna-Moreno Juan Francisco Villarreal-Chiu

This study examines the significant impact of bacterial, algal, and fungal toxins on foodborne illnesses, and stresses the importance of advanced detection techniques, such as high-performance liquid chromatography (HPLC)-based methodologies. It emphasizes the urgent need for further advancements in these techniques to ensure food safety, as they offer significant benefits, including low detection limits and the ability to be combined with other techniques to detect a wide range of toxins. In this regard, HPLC has emerged as a versatile and sensitive analytical technique for this purpose. Various HPLC methods, often enhanced with detectors such as ultraviolet (UV), fluorescence (FD), and mass spectrometry (MS), have been developed to identify and quantify microbial toxins in a wide variety of food samples. Recent advancements include HPLC-FD methods that utilize the natural fluorescence of certain aflatoxins, improving detection sensitivity. HPLC-MS/MS and UHPLC-MS/MS techniques offer high selectivity and sensitivity, making them suitable for detecting a wide range of toxins in trace quantities. The adaptability of HPLC, combined with innovative detection technologies and sample preparation methods, holds significant potential for enhancing food safety monitoring and reducing the global burden of foodborne diseases.