Search Results (1,443)

This work presents the first in-depth investigation of Theodor Aman’s paintings that focuses on three of his heritage artworks: “Hora de peste Olt” (1866), “Teleleice în Harem” (1879), and “Regimul vechi” (1881), and that relies on both elemental and spectroscopic analytical techniques. Non-destructive Raman spectroscopy was employed on all three works of art to identify the pigments used by the Romanian master. In addition, micro-samples were available from “Hora de peste Olt” and “Teleleice în Harem”, which were further analyzed using XRD, micro-Raman, ATR-FTIR, and SEM-EDS techniques to provide complementary information on the pigments. SEM-EDS was also applied to study the structure of the preparation layers. The analyses revealed significant differences between the artworks in terms of both the pigments employed and the preparation of the canvas, suggesting that the earlier artwork belongs to one creative phase, while the newer pieces can be attributed to a later phase in the artist’s career. Full article

Pheochromocytoma (PhC) and Paraganglioma (PG) are rare neuroendocrine tumors characterized by uncontrolled catecholamine secretion. Although rare, much attention is still devoted to identifying a unique biochemical signature of these diseases to reduce false positives, thus improving patient outcomes, and customizing clinical laboratory practices to available resources and specific diagnostic needs. Emerging knowledge into catecholamine metabolism has greatly improved diagnostic strategies, with current international guidelines recognizing plasma free or urinary fractionated metanephrine measurements as the recommended first-line biochemical tests. This narrative review highlights the clinical utility of measuring plasma free metanephrines compared to urinary catecholamines in the diagnosis of these conditions. Plasma free metanephrines offer superior sensitivity and specificity compared to catecholamines due to their continuous secretion, which is independent from tumor size and catecholamine fluctuations. This review also addresses preanalytical and methodological challenges, emphasizing patient preparation, sample stability and advanced analytical techniques currently available. Methodologies such as LC-MS/MS have demonstrated improved diagnostic accuracy compared to traditional immunoassays, offering enhanced analytical performance in terms of sensitivity, specificity, and reduced susceptibility to interferences. Full article

Microbial contamination in aquatic environments poses severe threats to aquaculture sustainability, ecological balance and public health. Traditional culture-based detection methods, while standardized, are time-consuming and labor-intensive, often failing to meet the urgent need for rapid on-site monitoring required to prevent disease outbreaks and manage water quality effectively. By integrating latest research advances (2020–2025), this study reviews advances in rapid detection technologies for aquatic microorganisms, including the evolution of nucleic acid amplification strategies, with a focused comparison of the analytical sensitivity and field deployability of quantitative polymerase chain reaction (qPCR) and mainstream isothermal amplification techniques (loop-mediated isothermal amplification, LAMP; recombinase polymerase amplification, RPA). Furthermore, this study reports on the emergence of Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-associated protein (Cas) systems as next-generation diagnostic tools, highlighting their integration with microfluidic Lab-on-a-Chip (LOC) platforms to achieve attomolar sensitivity. We also consider the application of portable nanopore sequencing for real-time pathogen identification and the growing role of Artificial Intelligence (AI) in analyzing complex diagnostic datasets. Advanced molecular methods have achieved significant reductions in time consumption—from days to less than one hour—while challenges regarding sample preparation and environmental matrix inhibition remain. The future of aquatic monitoring lies in integrated, automated systems that combine the specificity of CRISPR-Cas diagnostics with the connectivity of IoT-enabled biosensors. Comparative analysis indicates that isothermal amplification methods (LAMP, RPA) coupled with CRISPR-Cas systems offer the optimal balance of sensitivity, speed, and field deployability for point-of-care aquaculture diagnostics, while qPCR/dPCR remain indispensable for quantitative regulatory applications. We propose a structured technology selection framework to guide researchers and practitioners in choosing appropriate detection modalities based on specific sensitivity, cost, throughput, and deployment requirements. Full article

In authenticity checking of tobacco products, the identification of the varieties present is of primary importance. Nowadays the detection of illegal tobacco products is often based on package analysis and administrative verification, sometimes complemented with laboratory analysis. In this study an approach based on IR spectroscopy (MID-IR and NIR) for the identification of tobacco varieties in tobacco blends is proposed. Therefore, different blends were prepared, spectra were measured, and binary PLS-DA models were created. All models were evaluated and compared for their predictive performance, using both cross-validation (internal validation) and an external test set. For the best-performing model for each analyte the limit of detection was estimated. Finally, quantitative models were created to estimate the relative amount of one of the targeted varieties in the mixtures and a proof of concept using five commercial tobacco blends was performed. NIR proved to outperform MID-IR with maximum values of correct classification rate, precision, specificity, and accuracy for four varieties and only one misclassification for the two remaining ones. Indicative limit of detection values were obtained between 1 and 8%. Quantitative errors were all smaller than 5%. These values as well as the application to commercial samples proved the feasibility of the presented approach and its potential value as tool in the fight against fraud and counterfeited tobacco products. Full article

X ray photoelectron spectroscopy (XPS) is a key technique routinely employed for the chemical analysis of alloy surfaces, enabling precise nanoscale characterization of near surface elemental composition and chemical states. This review outlines the fundamental principles of XPS, typical data analysis workflows, and critical analytical considerations specific to alloy systems. Given the propensity for oxidation, multicomponent nature, and heterogeneous phase characteristics of alloys, standardized protocols are reviewed for sample preparation, binding energy calibration, peak fitting, quantitative analysis, and depth profiling. For conductive alloys, calibration using the Fermi edge or gold reference standards is specified, and the use of Auger parameters is highlighted to improve the reliability of chemical state identification. This article also systematically summarizes applications of XPS in corrosion protection, high temperature oxidation, surface modification, phase transformation, and failure analysis. It is emphasized that near surface chemical information must be validated in combination with bulk phase, microstructural, and electrochemical characterization to rationally establish relationships between surface chemistry and macroscopic performance. Finally, recent advances in near ambient pressure, in situ, high resolution, and intelligent XPS techniques are reviewed, providing a standardized reference and technical support for alloy research. Full article

Per- and polyfluoroalkyl substances (PFAS) are highly stable and persistent environmental contaminants. Their exceptional chemical stability prevents natural breakdown, leading to global distribution and bioaccumulation in aquatic organisms. Long-chain PFAS, such as perfluorooctane sulfonic acid (PFOS), tend to accumulate in the liver, kidneys, and muscle tissues, whereas short-chain PFAS remain largely dissolved in water and show lower accumulation. Freshwater fish generally contain higher PFAS levels than marine fish, with concentrations varying according to species, habitat, trophic level, contamination site, and other factors. Human exposure primarily occurs through the consumption of contaminated fish and seafood, as well as through drinking water, inhalation, and skin contact. Such exposure is associated with immunosuppression, high cholesterol, hormonal disruption, cancer, and other health risks. Regulatory limits exist for four PFAS compounds, while many others, including emerging compounds, remain unregulated. This review synthesizes the current knowledge on the global distribution of PFAS across various fish species, analytical approaches including sample preparation (e.g., SPE, QuEChERS) and instrumental techniques (e.g., LC-MS/MS, HRMS), human dietary exposure, and the related health risks. By integrating environmental distribution, bioaccumulation, analytical challenges, and health issues, this review provides an up-to-date perspective on PFAS in fish and emphasizes the need for ongoing monitoring and stricter regulatory frameworks to ensure food safety and protect both human health and ecosystems. Full article

Sensitive detection of Escherichia coli O157:H7 (E. coli O157:H7) in food matrices remains an important analytical challenge. Here, a colorimetric biosensor was constructed based on a bimetal oxide nanozyme composed of Ce-Fe oxide. This biosensor achieved sensitive detection of E. coli O157:H7. The Ce-Fe oxide synthesized on the basis of deep eutectic solvents (DESs) had the advantages of low solvent consumption and short preparation time. By regulating the two key factors of metal valence and oxygen vacancy content, the peroxidase (POD) activity of the nanozyme was significantly improved. Compared with the single-metal oxide nanozyme Fe oxide, the addition of Ce increased the Fe²⁺/Fe³⁺ ratio from 0.37 to 0.49, implying a possible enhancement of electron transfer between Fe²⁺ and Fe³⁺. The detection limits (LODs) of the biosensor based on Fe oxide and that based on Ce-Fe oxide were 10² CFU/mL and 10¹ CFU/mL, respectively, comparable to existing validated methods. Moreover, these two biosensors achieved satisfactory recovery rates (91–104%) and RSDs (1.2–8.8%) in the spiked lake water, juice, and lettuce samples of E. coli O157:H7, indicating their high potential for application in spiked sample detection. In summary, the method proposed in this study for improving the POD activity of nanozymes through electron transfer in DES solutions is beneficial to the development of metal oxide nanozymes. Full article

Background noise and intensive sample preparation frequently compromise the field screening of Bacillus anthracis. Addressing these analytical bottlenecks, we constructed a giant magnetoresistive (GMR) biosensor incorporating geometrically tailored trapezoidal magnetic flux concentrators (MFCs). 3D finite element magnetic simulations directed the MFC topology to mitigate edge saturation, reconciling central magnetic gain with spatial uniformity. The resulting platform demonstrated a 100-fold sensitivity improvement over recent electrochemical methods, achieving a limit of detection (LOD) of 10 CFU/mL in standard buffers, with the entire testing process completed within 40 min. Direct target quantification remained viable in heterogeneous matrices—muddy water, whole milk, and apple cider—circumventing tedious pretreatment. This geometric and magnetic optimization yields a pragmatic sensing architecture tailored for on-site biodefense monitoring. Full article

Blood glutathione (GSH), its oxidized form glutathione disulfide (GSSG), and especially the ratio of reduced to oxidized glutathione (GSH/GSSG) are recognized as robust biomarkers of oxidative stress. However, the broader application of these biomarkers has been limited by two major challenges: (1) the high risk of artifact formation during sample handling, which can artificially increase GSSG levels and bias redox balance measurements, and (2) the reliance on complex, instrument-intensive analytical procedures and the requirement for venous blood. We present an adaptation of the highly sensitive and easy-to-perform Tietze recycling method for microvolumes of blood. The challenge is to achieve accurate and precise measurements while avoiding artifacts, taking advantage of the high sensitivity of this enzymatic recycling analytical procedure. The method uses a simplified sample preparation protocol compatible with small blood volumes (up to 10 μL) and requires only basic laboratory equipment, such as a standard spectrophotometer or microplate reader. As this is an enzyme-based assay, we also carefully evaluate the main factors that can affect the measurements. This novel procedure provides a practical tool for monitoring GSH/GSSG as a biomarker of oxidative stress in various experimental settings by eliminating the need for trained personnel for blood sampling (it is suitable for capillary blood), minimizing discomfort for subjects, and avoiding complex procedures or instruments for analyte detection. Full article

A comprehensive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous quantification of 50 pesticide biomarkers across nine current-use chemical classes in human urine. These classes include organophosphorus insecticides (which encompass dialkyl phosphates and specific metabolites), pyrethroid insecticides, fungicides, neonicotinoid insecticides, herbicides, insect repellents, organochlorine pesticide metabolites, and plant growth regulators. The method employs solid-phase extraction (SPE) for sample preparation, requiring only 0.2 mL of urine. Chromatographic separation was optimized using a Hypersil Gold AQ column, achieving a total run time of 18 min. Mass spectrometric detection utilized polarity switching in electrospray ionization mode with multiple reaction monitoring. Method validation demonstrated satisfactory linearity (R² > 0.99), high sensitivity with limits of detection ranging from 0.01 to 0.88 ng/mL, and extraction efficiencies between 85% and 113%. Precision and accuracy were within acceptable ranges, with relative standard deviations generally below 15%. The method’s robustness was confirmed through participation in external quality assessment schemes. Application to real samples revealed significant inter-individual variability in pesticide biomarker concentrations, with total measured biomarker levels ranging from 89 to 1242 ng/mL across the 10 individuals analyzed. This method offers comprehensive coverage of current-use pesticide chemical classes, including 30 biomarkers from the U.S. National Health and Nutrition Examination Survey (NHANES) biomonitoring program, and demonstrates improved sensitivity and broader analyte coverage compared to existing methods. The developed assay provides a valuable tool for large-scale biomonitoring studies and environmental health research. Full article

Pesticide residues represent an important group of chemical contaminants in agricultural commodities and require reliable analytical strategies for accurate monitoring. In this study, a high-throughput analytical workflow was applied for the determination of 210 pesticide residues in gherkins. Sample preparation was performed using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method, including extraction followed by dispersive solid-phase extraction clean-up. Residue determination was carried out using liquid chromatography–tandem mass spectrometry (LC-MS/MS) and gas chromatography–tandem mass spectrometry (GC-MS/MS). The analytical methods were comprehensively validated in the gherkin matrix in accordance with the SANTE 11312/2021 v2 guidelines. Limits of quantification were ≤0.01 mg kg⁻¹ for all compounds. Recovery values ranged from 75.7% to 113.7%, while precision values remained below 20%, demonstrating satisfactory method accuracy and precision. Expanded measurement uncertainty values ranged between 7.6% and 41.3%, confirming the robustness of the validated analytical workflow. The validated methods were subsequently applied to a large-scale monitoring dataset comprising 905 gherkin samples collected from five major production regions in Türkiye. Pesticide residues were detected in 67.6% of the analysed samples, and 37 different compounds were identified. The most frequently detected pesticides were flonicamid (36.2%) and propamocarb (27.5%). Multi-residue contamination was frequently observed, reflecting complex pesticide application patterns in gherkin cultivation systems. Although chronic exposure estimates remained well below toxicological thresholds for both adults and children, certain exposure scenarios indicated that acute exposure for children may warrant further attention. Full article

Escherichia coli (E. coli) is a microorganism commonly found in water and food matrices, and its rapid and accurate detection is crucial for maintaining public health and ensuring food safety. However, traditional molecularly imprinted polymer (MIP) sensors often face challenges such as tedious template removal and prolonged sensing times. This study develops a label-free bacterial molecularly imprinted sensor that utilizes the synergistic effect of polypyrrole (PPy) and multi-walled carbon nanotubes (MWCNTs) to achieve highly sensitive detection of E. coli. Based on the large specific surface area and superior conductivity of MWCNTs, as well as the favorable electrochemical polymerization properties of PPy, a PPy/MWCNTs composite film was fabricated via a one-step electropolymerization process. The prepared sensor exhibited excellent kinetic characteristics, with a template removal time of only 15 min, and could be regenerated and used for subsequent detection within 30 min. Under optimized conditions, the biosensor showed a satisfactory linear response over the concentration range of 10²–10⁸ CFU/mL, with a low detection limit of 65 CFU/mL (3σ/S). Furthermore, recovery experiments conducted in tap water and lemon juice samples yielded satisfactory recoveries ranging from 87.1% to 114.8%, demonstrating the reliability and practical applicability of the proposed sensor for bacterial detection in real samples. This sensor offers advantages such as simple preparation, low material cost, and high sensitivity, providing a reliable and practical analytical platform for the rapid and reliable detection of bacteria. Full article

Background/Objectives: Epirubicin, Olaparib, and Ribociclib are widely used anticancer agents whose serum concentrations exhibit significant inter-individual variability, supporting the need for reliable and robust analytical methods suitable for pharmacokinetic evaluation and therapeutic exposure assessment. Variations in metabolism, drug–drug interactions, organ function, and treatment regimens may substantially influence systemic exposure, highlighting the importance of accurate quantification in clinical practice. This study describes the development and validation of a solid-phase extraction–liquid chromatography–mass spectrometry (SPE–LC–MS) method for the simultaneous quantification of these drugs in human serum. Methods: Sample preparation was performed using Oasis PRiME HLB^® cartridges to ensure efficient clean-up, optimal recovery, and reduced matrix effects. Chromatographic separation was achieved using gradient elution with 0.1% formic acid and acetonitrile on a reversed-phase column, followed by single-quadrupole mass spectrometric (QDa) detection in the selected ion recording mode. The total run time was 13 min, enabling high-throughput analysis. Results: The method demonstrated good linearity (r > 0.997) over the tested concentration ranges, along with adequate selectivity, precision, accuracy, recovery, and stability, fulfilling the ICH M10 guideline validation criteria. No significant carry-over or interference from endogenous compounds was observed. Conclusions: Application to patient samples confirmed reliable performance in real clinical matrices and consistent quantification across different concentration levels. The proposed approach provides a potentially more accessible alternative in laboratories already equipped with LC-MS systems compared to LC-MS/MS platforms and can be applied in pharmacokinetic studies, representing a proof-of-concept for exposure assessment in oncology. Full article

In this study, an ion-pair reverse-phase high-performance liquid chromatography–electrospray ionization mass spectrometry (RP-HPLC-ESI-MS) method was optimized and validated for purity determination for the quality control of the proposed generic nusinersen oligonucleotide drug substance and drug product. The optimization and considerations of sample preparation, chromatographic and mass spectrometry conditions are discussed. The limit of detection was 2.5 × 10⁻⁵ mg/mL and the limit of quantitation was 4.9 × 10⁻⁵ mg/mL. The linearity of the signal (XIC) for all impurities was linear with correlation coefficients of R² ≥ 0.9669. This study, associated with the development of therapeutic oligonucleotides, examines the subject of product-related impurities. The authors consider an ion-pair reverse-phase high-performance liquid chromatography in combination with mass spectrometry for impurity quantitative control. This study contributes to the field by elucidating several critical aspects that, while previously unaddressed in the existing literature, are essential for developing effective analytical methods. Full article

Background/Objectives: Pharmacogenomics (PGx) enables personalized therapy by identifying genetic variants that influence drug response. Despite the advantages of next-generation sequencing (NGS), few clinically validated, guideline-aligned panels comprehensively detect common, rare, and structurally complex pharmacogenetic variants. Methods: We developed and analytically validated Action PharmaKitDx, a targeted NGS panel covering 335 pharmacogenes, including all priority genes recommended by CPIC, DPWG, and CPNDS. Performance was assessed using Coriell HapMap and GeT-RM reference materials across multiple library preparation workflows and Illumina platforms. Clinical feasibility was evaluated in 41 patient samples from diverse specialties. Results were compared with established reference methods, including PCR-based assays, STR analysis, Sanger sequencing, and whole-exome sequencing. Results: Analytical validation: More than 99% of target bases achieved ≥30× coverage. Analytical accuracy, sensitivity, specificity, and positive predictive value exceeded 99.3%, with repeatability and reproducibility >99.7%. Concordance with GeT-RM haplotypes reached 98% after star-allele harmonization. The panel accurately detected complex variants, including CYP2D6 copy-number changes and hybrid alleles. Clinical validation: Full concordance with prior genotyping was observed in clinical samples. Beyond the initial testing indication, each sample harbored a mean of six actionable variants (range 2–10). Thirty-six rare (minor allele frequency <1%) potentially actionable variants were additionally identified. Conclusions: Action PharmaKitDx demonstrates high analytical performance and broad clinical applicability, supporting its implementation as a scalable solution for comprehensive pharmacogenetic testing and precision prescribing. Full article