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12 pages, 1231 KiB

Open AccessArticle

Enantio- and Chemo-Selective HPLC Analysis of Silodosin on an Amylose-Based Chiral Stationary Phase

by Daniele Sadutto, Francesca Romana Mammone, Giulia D’Ettorre, Leo Zanitti, Daniela De Orsi, Romina Alfonsi, Francesca Prestinaci and Roberto Cirilli

Molecules 2025, 30(9), 1966; https://doi.org/10.3390/molecules30091966 - 29 Apr 2025

Viewed by 108

Abstract

A direct enantio- and chemo-selective high-performance liquid chromatographic method was developed for determining the enantiomeric impurity of the chiral active pharmaceutical ingredient silodosin. The simultaneous separation of enantiomers of silodosin and its main organic related substances listed in the Japanese Pharmacopoeia (JP) monograph [...] Read more.

A direct enantio- and chemo-selective high-performance liquid chromatographic method was developed for determining the enantiomeric impurity of the chiral active pharmaceutical ingredient silodosin. The simultaneous separation of enantiomers of silodosin and its main organic related substances listed in the Japanese Pharmacopoeia (JP) monograph for drug substance was achieved on Chiralpak AD-3 (250 mm × 4.6 mm, 3 μm) column under normal-phase isocratic conditions. The optimized conditions employed the mixture n-heptane-ethanol-diethylamine (70:30:0.1) (v/v/v) as a mobile phase and a temperature of 35 °C. The complete separation of the enantiomers of silodosin and its main impurities was obtained within 12 min. The chromatographic method has been validated according to the International Conference on Harmonization (ICH) guidelines and compared with the method reported in the JP monograph. The standard curve for silodosin exhibited linearity (R² > 0.999) within the concentration range of 1.13–2500 µg mL⁻¹. The Chiralpak AD-3 has demonstrated a remarkable level of efficiency, enabling the attainment of limits of quantitation for silodosin of 1.13 µg mL⁻¹ (equivalent to 0.057% of a sample solution of 2 mg mL⁻¹) and ranging from 0.48 µg mL⁻¹ to 1.94 µg mL⁻¹ for other impurities. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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20 pages, 7306 KiB

Open AccessArticle

Chemical Composition and Bioactivity of Extracts Obtained from Prunus spinosa Seeds by Supercritical CO₂ Extraction

by Alessandra Piras, Silvia Porcedda, Antonella Smeriglio, Domenico Trombetta, Franca Piras, Valeria Sogos and Antonella Rosa

Molecules 2025, 30(8), 1757; https://doi.org/10.3390/molecules30081757 - 14 Apr 2025

Viewed by 187

Abstract

This study investigates the potential reuse of Prunus spinosa (blackthorn) seeds, a food industry by-product. Traditionally discarded, these seeds are now being explored for their bioactive compounds. In this work, seeds were used as raw material for supercritical CO₂ extraction. Two distinct [...] Read more.

This study investigates the potential reuse of Prunus spinosa (blackthorn) seeds, a food industry by-product. Traditionally discarded, these seeds are now being explored for their bioactive compounds. In this work, seeds were used as raw material for supercritical CO₂ extraction. Two distinct extracts were obtained at low and high pressure (SFE90 and SFE200) and both extracts presented an aqueous phase (WE90 and WE200). SFE90 analysis by GC/MS allowed us to identify benzaldehyde and fatty acids (mainly oleic and linoleic acids). The fatty acid profile of SFE200, determined by HPLC-DAD/ELSD, showed that oleic and linoleic acids were predominant in supercritical oil. The phytochemical composition of the water extracts, analyzed via LC-DAD-ESI-MS, revealed that higher pressure enhanced the recovery of specific flavonols and anthocyanins, while lower pressure preserved various polyphenolic subclasses. WE90 was rich in 3-feruloylquinic acid and cyanidin-3-O-rutinoside, whereas WE200 was rich in caffeic acid hexoside 2 and dihydro-o-coumaric acid glucoside. Benzaldehyde was individuated in WE90 and WE200 by HPLC-DAD analysis. Cytotoxicity assays demonstrated that WE90, WE200 and SFE200 had anticancer effects on SH-SY5Y neuroblastoma cells, while all extracts did not remarkably affect the viability and morphology of human skin keratinocytes (HaCaT cells). These results suggest that P. spinosa seed extracts have potential nutraceutical and pharmaceutical applications. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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23 pages, 2096 KiB

Open AccessFeature PaperArticle

Long-Term Variability in the Content of Some Metals and Metalloids in Aesculus Flowers: A Four-Year Study Using ICP OES and PCA Analysis

by Veronica D’Eusanio, Elia Frignani, Andrea Marchetti, Laura Pigani, Mirco Rivi and Fabrizio Roncaglia

Molecules 2025, 30(4), 908; https://doi.org/10.3390/molecules30040908 - 15 Feb 2025

Viewed by 566

Abstract

This study investigates the content of some metals and metalloids in the flowers of three Aesculus cultivars (AHP, Aesculus hippocastanum pure species, with white flowers; AHH, Aesculus hippocastanum hybrid species, with pink flowers; and AXC, Aesculus × carnea, with red flowers) over [...] Read more.

This study investigates the content of some metals and metalloids in the flowers of three Aesculus cultivars (AHP, Aesculus hippocastanum pure species, with white flowers; AHH, Aesculus hippocastanum hybrid species, with pink flowers; and AXC, Aesculus × carnea, with red flowers) over a four-year period (2016–2019) using inductively coupled plasma optical emission spectrometry (ICP OES) and principal component analysis (PCA). The research focuses on assessing macro- and micro-elemental compositions, identifying variations in mineral uptake, and exploring potential correlations with soil composition. Results highlight significant differences in elemental profiles among the three species, despite similar total ash content. Potassium and phosphorus emerged as dominant macroelements, with AXC showing lower magnesium levels compared to AHP and AHH. Particularly intriguing was the detection of antimony in all cultivars, raising questions about its role and bioaccumulation pathways in floral tissues. Iron and aluminum concentrations varied significantly across species, indicating species-specific metal transport mechanisms. Nickel content showed temporal fluctuations, potentially influenced by climatic conditions and soil properties. PCA revealed distinct clustering patterns, linking elemental concentrations to specific species and years. This comprehensive analysis enhances understanding of metal absorption and distribution in ornamental plants, providing insights into their metabolic processes and potential implications for environmental monitoring and phytoremediation strategies. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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12 pages, 1931 KiB

Open AccessArticle

Voltammetric Determination of the Total Content of the Most Commonly Occurring Estrogens in Water Media

by Jaromíra Chýlková, Jan Bartáček, Natálie Měchová, Miloš Sedlák and Jiří Váňa

Molecules 2025, 30(3), 751; https://doi.org/10.3390/molecules30030751 - 6 Feb 2025

Viewed by 583

Abstract

Estrogens in aquatic environments pose significant ecological and health risks due to their cumulative effects rather than individual impacts. This study investigates the voltammetric behavior of estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2), presenting a cost-effective and straightforward method for their [...] Read more.

Estrogens in aquatic environments pose significant ecological and health risks due to their cumulative effects rather than individual impacts. This study investigates the voltammetric behavior of estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2), presenting a cost-effective and straightforward method for their simultaneous determination. Using differential pulse voltammetry (DPV) with a boron-doped diamond electrode, the method demonstrates high precision (deviations under 4%) and a linear dynamic range of 15.35–134.55 µmol·L⁻¹. Integration of a vacuum evaporation step reduced detection limits to 10⁻⁸ mol·L⁻¹, enabling effective analysis of real water samples. This optimized approach ensures practical applicability for monitoring total estrogen content in aquatic systems, providing an accessible and reliable alternative to conventional methods. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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13 pages, 1206 KiB

Open AccessArticle

Machine Learning-Based Spectral Analyses for Camellia japonica Cultivar Identification

by Pedro Miguel Rodrigues and Clara Sousa

Molecules 2025, 30(3), 546; https://doi.org/10.3390/molecules30030546 - 25 Jan 2025

Viewed by 640

Abstract

Camellia japonica is a plant species with high cultural and biological relevance. Besides being used as an ornamental plant species, C. japonica has relevant biological properties. Due to hybridization, thousands of cultivars are known, and their accurate identification is mandatory. Infrared spectroscopy is [...] Read more.

Camellia japonica is a plant species with high cultural and biological relevance. Besides being used as an ornamental plant species, C. japonica has relevant biological properties. Due to hybridization, thousands of cultivars are known, and their accurate identification is mandatory. Infrared spectroscopy is currently recognized as an accurate and rapid technique for species and/or subspecies identifications, including in plants. However, selecting proper analysis tools (spectra pre-processing, feature selection, and chemometric models) highly impacts the accuracy of such identifications. This study tests the impact of two distinct machine learning-based approaches for discriminating C. japonica cultivars using near-infrared (NIR) and Fourier transform infrared (FTIR) spectroscopies. Leaves infrared spectra (NIR—obtained in a previous study; FTIR—obtained herein) of 15 different C. japonica cultivars (38 plants) were modeled and analyzed via different machine learning-based approaches (Approach 1 and Approach 2), each combining a feature selection method plus a classifier application. Regarding Approach 1, NIR spectroscopy emerged as the most effective technique for predicting C. japonica cultivars, achieving 81.3% correct cultivar assignments. However, Approach 2 obtained the best results with FTIR spectroscopy data, achieving a perfect 100.0% accuracy in cultivar assignments. When comparing both approaches, Approach 2 also improved the results for NIR data, increasing the correct cultivar predictions by nearly 13%. The results obtained in this study highlight the importance of chemometric tools in analyzing infrared data. The choice of a specific data analysis approach significantly affects the accuracy of the technique. Moreover, the same approach can have varying impacts on different techniques. Therefore, it is not feasible to establish a universal data analysis approach, even for very similar datasets from comparable analytical techniques. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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13 pages, 7101 KiB

Open AccessArticle

New Long-Term Use Solid Bismuth Microelectrode Arrays for Rapid and Sensitive Determination of Sunset Yellow in Isotonic Beverages and Water Samples by Adsorptive Stripping Voltammetry

by Mieczyslaw Korolczuk, Iwona Gęca, Artur Mazurek and Paulina Mrózek

Molecules 2025, 30(2), 345; https://doi.org/10.3390/molecules30020345 - 16 Jan 2025

Viewed by 631

Abstract

This article reports on the long-term use, solid bismuth microelectrode arrays for the first time. The presented working microelectrode is characterized by particular advantages compared to bismuth film electrodes and solid single bismuth microelectrodes; these advantages include environmentally friendly properties and the amplification [...] Read more.

This article reports on the long-term use, solid bismuth microelectrode arrays for the first time. The presented working microelectrode is characterized by particular advantages compared to bismuth film electrodes and solid single bismuth microelectrodes; these advantages include environmentally friendly properties and the amplification of recorded currents, which are subsequently more resistant to interference. The proposed solid bismuth microelectrode array was applied to develop an adsorptive stripping voltammetric procedure for Sunset Yellow determination. The main experimental parameters were optimized. The calibration graph was linear from 5 × 10⁻⁹ to 1 × 10⁻⁷ mol L⁻¹ (time of accumulation, 60 s). The detection limit was equal to 1.7 × 10⁻⁹ mol L⁻¹. The relative standard deviation for a concentration of Sunset Yellow of 2 × 10⁻⁸ mol L⁻¹ was 4.1% (n = 7). Potential interference effects were examined. The presented analytical procedure was applied for the determination of Sunset Yellow in isotonic beverages and the results were confirmed by HPLC as a comparative method. The correctness of the presented procedure was also confirmed by satisfactory recovery values obtained during the analysis of spiked environmental water samples. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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16 pages, 5870 KiB

Open AccessArticle

Analysis of Plasticizer Contamination Throughout Olive Oil Production

by Flávia Freitas, João Brinco, Maria João Cabrita and Marco Gomes da Silva

Molecules 2024, 29(24), 6013; https://doi.org/10.3390/molecules29246013 - 20 Dec 2024

Viewed by 1116

Abstract

This study monitored the contamination of 32 plasticizers in olive oil throughout the production and storage process. Samples were collected at different stages of production from three olive oil production lines in distinct regions of Portugal and analyzed for 23 phthalates and 9 [...] Read more.

This study monitored the contamination of 32 plasticizers in olive oil throughout the production and storage process. Samples were collected at different stages of production from three olive oil production lines in distinct regions of Portugal and analyzed for 23 phthalates and 9 phthalates substitutes to identify contamination sources. The developed analytical method employed liquid–liquid extraction with hexane/methanol (1:4, v/v), followed by centrifugation, extract removal, and freezing as a clean-up step. Analysis was conducted using gas chromatography tandem mass spectrometry (GC-MS/MS), with detection limits ranging from 0.001 to 0.103 mg/kg. The results revealed that plasticizer concentrations progressively increased at each stage of the production process, although unprocessed olives also contained contaminants. Di-isononyl phthalate (DINP) was the most prevalent compound, but all phthalates regulated by the European Union for food contact materials were detected, as well as some unregulated plasticizers. In a few packaged olive oils, DINP concentrations exceeded the specific migration limits established by European regulations. Samples stored in glass and plastic bottles showed no significant differences in plasticizer concentrations after six months of storage. However, higher concentrations were observed in plastic-packaged samples after 18 months of storage. Our findings indicate that the primary source of plasticizer contamination in olive oil originates from the production process itself, except for prolonged storage in plastic bottles, which should be avoided. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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26 pages, 1657 KiB

Open AccessArticle

Analysis Profiling of 48 Endogenous Amino Acids and Related Compounds in Human Plasma Using Hydrophilic Interaction Liquid Chromatography–Tandem Mass Spectrometry

by Xiongwei Yin, Irene Baldoni, Erwin Adams and Ann Van Schepdael

Molecules 2024, 29(24), 5993; https://doi.org/10.3390/molecules29245993 - 19 Dec 2024

Viewed by 947

Abstract

Analyzing and detecting endogenous amino acids in blood is of crucial importance for the diagnosis of medical conditions and scientific research. Considering the lack of UV chromophores in most of these analytes and the presence of several interfering substances in plasma, the quantification [...] Read more.

Analyzing and detecting endogenous amino acids in blood is of crucial importance for the diagnosis of medical conditions and scientific research. Considering the lack of UV chromophores in most of these analytes and the presence of several interfering substances in plasma, the quantification of quite a few amino acids and related compounds presents certain technical challenges. As a blank plasma matrix lacking these endogenous substances does not exist, the surrogate matrix method is used, as well as isotopic internal standards for calibration, to ensure the accuracy and reliability of the study. Method validation was conducted for 48 target analytes, giving the following results: linearity (R² at least 0.99), limit of quantification (from 0.65 to 173.44 μM), precision (intra-day and inter-day RSD for LQC ranged from 3.2% to 14.2%, for MQC from 2.0% to 13.6%, and for HQC from 1.6% to 11.3%), accuracy, recovery, and stability of the method (all complied with the guidelines). To further investigate the applicability of this method to large-scale sample analysis, the method was successfully applied to the analysis of amino acids in plasma samples collected from 20 control individuals, demonstrating its wide application scope for clinical diagnosis and metabolic research. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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29 pages, 3178 KiB

Open AccessArticle

Lighting the Path: Raman Spectroscopy’s Journey Through the Microbial Maze

by Markus Salbreiter, Sandra Baaba Frempong, Sabrina Even, Annette Wagenhaus, Sophie Girnus, Petra Rösch and Jürgen Popp

Molecules 2024, 29(24), 5956; https://doi.org/10.3390/molecules29245956 - 17 Dec 2024

Viewed by 1761

Abstract

The rapid and precise identification of microorganisms is essential in environmental science, pharmaceuticals, food safety, and medical diagnostics. Raman spectroscopy, valued for its ability to provide detailed chemical and structural information, has gained significant traction in these fields, especially with the adoption of [...] Read more.

The rapid and precise identification of microorganisms is essential in environmental science, pharmaceuticals, food safety, and medical diagnostics. Raman spectroscopy, valued for its ability to provide detailed chemical and structural information, has gained significant traction in these fields, especially with the adoption of various excitation wavelengths and tailored optical setups. The choice of wavelength and setup in Raman spectroscopy is influenced by factors such as applicability, cost, and whether bulk or single-cell analysis is performed, each impacting sensitivity and specificity in bacterial detection. In this study, we investigate the potential of different excitation wavelengths for bacterial identification, utilizing a mock culture composed of six bacterial species: three Gram-positive (S. warneri, S. cohnii, and E. malodoratus) and three Gram-negative (P. stutzeri, K. terrigena, and E. coli). To improve bacterial classification, we applied machine learning models to analyze and extract unique spectral features from Raman data. The results indicate that the choice of excitation wavelength significantly influences the bacterial spectra obtained, thereby impacting the accuracy and effectiveness of the subsequent classification results. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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11 pages, 2546 KiB

Open AccessArticle

Improved Detection of Polysulfated Oligosaccharides by Mass Spectrometry Applicable to Miniaturized Samples

by Frédéric Jeanroy, Julie Gil, Clothilde Comby-Zerbino, Claire Demesmay and Vincent Dugas

Molecules 2024, 29(23), 5642; https://doi.org/10.3390/molecules29235642 - 28 Nov 2024

Viewed by 755

Abstract

The study of biomolecules and their interactions in their natural environment requires increasingly sophisticated technological and methodological developments. The complexity of these developments is due, among other things, to the nature of these molecules and the small quantities available depending on their origin. [...] Read more.

The study of biomolecules and their interactions in their natural environment requires increasingly sophisticated technological and methodological developments. The complexity of these developments is due, among other things, to the nature of these molecules and the small quantities available depending on their origin. In this context, this study focuses on the conditions for improving the detection of glycosaminoglycans on a miniaturized scale by mass spectrometry. These multicharged anionic linear polysaccharides are in fact difficult to study by mass spectrometry and can present, for a given molecule, a large number of signals linked to different charge states, to the loss of one or more sulfate groups and to the presence of different adducts, which reduces sensitivity and complicates the interpretation of the spectra. In order to reduce this complexity, we have investigated different sample preparation methods applicable to small sample volumes. The development of home-made capillary ion-exchange columns, for example, makes it possible to control the adducts formed in nano-ESI coupling. However, their use on a miniaturized scale for detection by MALDI-TOF-MS does not allow for performances as high as those obtained with treatment with a commercial DOWEX^TM resin. However, experimental results allowed us to demonstrate that the presence of DOWEX^TM resin colloid residues in the aqueous phase greatly improves the quality of the spectra obtained by MALDI-TOFMS on a Fondaparinux model glycosaminoglycan. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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22 pages, 1495 KiB

Open AccessArticle

Study of Endocrine-Disrupting Chemicals in Infant Formulas and Baby Bottles: Data from the European LIFE-MILCH PROJECT

by Francesca Nuti, Feliciana Real Fernández, Mirko Severi, Rita Traversi, Vassilios Fanos, Maria Elisabeth Street, Paola Palanza, Paolo Rovero and Anna Maria Papini

Molecules 2024, 29(22), 5434; https://doi.org/10.3390/molecules29225434 - 18 Nov 2024

Cited by 1 | Viewed by 1677

Abstract

Exposure to endocrine-disrupting chemicals (EDCs) is inevitable, and growing scientific evidence indicates that even very low doses can negatively impact human health, particularly during pregnancy and the neonatal period. As part of the European project LIFE18 ENV/IT/00460, this study aims to identify the [...] Read more.

Exposure to endocrine-disrupting chemicals (EDCs) is inevitable, and growing scientific evidence indicates that even very low doses can negatively impact human health, particularly during pregnancy and the neonatal period. As part of the European project LIFE18 ENV/IT/00460, this study aims to identify the presence of EDCs in 20 infant formulas (both powdered and liquid) and the release from baby bottles and teats. Particularly, sensitization of young people and future parents towards the potential harmful effects of EDCs could significantly help to reduce exposure. Seven different UPLC-MS/MS methodologies and one ICP-AES were set up to quantify already assessed and suspected EDCs among 85 different chemicals (bisphenols, parabens, PAHs, phthalates, pesticides, herbicides and their main metabolites, PFAS, and metals). Results showed that in 2 out of 14 baby bottles, only anthracene and phenanthrene of the group of PAHs were released (10.68–10.81 ng/mL). Phthalates such as mono-ethyl phthalate (MEP) were found in 9 of 14 samples (0.054–0.140 ng/mL), while mono(2-ethyl-5-oxohexyl) phthalate (MeOHP) appeared in 2 samples (0.870–0.930 ng/mL). In accordance with current EU regulations, other chemicals were not detected in baby bottles and teats. However, bisphenols, parabens, PAHs, phthalates, PFAS, and metals were detected in infant formula, emphasizing the need for continued monitoring and public health interventions. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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23 pages, 3017 KiB

Open AccessArticle

Structural Characterization and Profiles of Saponins from Two Algerian Sea Cucumbers

by Ihcene Khodja, Karim Mezali, Philippe Savarino, Pascal Gerbaux, Patrick Flammang and Guillaume Caulier

Molecules 2024, 29(22), 5346; https://doi.org/10.3390/molecules29225346 - 13 Nov 2024

Viewed by 1366

Abstract

Sea cucumbers are benthic marine invertebrate members of the phylum Echinodermata. Due to the absence of a rigid skeleton, these species have developed chemical defenses based on the production of saponins (triterpene glycosides). These secondary metabolites are bioactive molecules with a broad biological, [...] Read more.

Sea cucumbers are benthic marine invertebrate members of the phylum Echinodermata. Due to the absence of a rigid skeleton, these species have developed chemical defenses based on the production of saponins (triterpene glycosides). These secondary metabolites are bioactive molecules with a broad biological, ecological, and pharmaceutical spectrum. However, the saponin profiles of several species of sea cucumbers are not known yet. The present study aims to highlight the mixture of saponins in two sea cucumber species from the Algerian coast, namely Holothuria (Holothuria) algeriensis, which has been recently described in central and western Algerian waters, and Holothuria (Roweothuria) arguinensis, originating from the Atlantic Ocean and reported in Algeria for the first time in 2014. Saponin extracts from three individuals of H. (H.) algeriensis and two individuals of H. (R.) arguinensis were analyzed using mass spectrometry, i.e., Matrix-assisted Laser Desorption/Ionization mass spectrometry (MALDI-MS), MALDI-High Resolution MS (MALDI-HRMS), Liquid Chromatography MS (LC-MS) and tandem MS (LC-MS/MS). These analyses allow us to detect 11 and 18 elemental compositions for H. (H.) algeriensis and H. (R.) arguinensis, respectively, each presenting several isomers. In total, 13 new saponin structures are proposed, of which four are common between the two species, six are specific to H. (H.) algeriensis and three to H. (R.) arguinensis. The saponin profiles of the two species were compared to those of other species of the same genus existing on the Algerian coast and the results showed that they share non-sulfated saponins with Holothuria (Panningothuria) forskali and Holothuria (Platyperona) sanctori and sulfated saponins with Holothuria (Holothuria) tubulosa and Holothuria (Roweothuria) poli. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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15 pages, 3766 KiB

Open AccessArticle

Investigation of the Frying Fume Composition During Deep Frying of Tempeh Using GC-MS and PTR-MS

by Rohmah Nur Fathimah and Tomasz Majchrzak

Molecules 2024, 29(21), 5046; https://doi.org/10.3390/molecules29215046 - 25 Oct 2024

Viewed by 856

Abstract

This study employed proton transfer reaction mass spectrometry (PTR-MS) and gas chromatography–mass spectrometry (GC-MS) to identify and monitor volatile organic compounds (VOCs) in frying fumes generated during the deep frying of tempeh. The research aimed to assess the impact of frying conditions, including [...] Read more.

This study employed proton transfer reaction mass spectrometry (PTR-MS) and gas chromatography–mass spectrometry (GC-MS) to identify and monitor volatile organic compounds (VOCs) in frying fumes generated during the deep frying of tempeh. The research aimed to assess the impact of frying conditions, including frying temperature, oil type, and repeated use cycles, on the formation of thermal decomposition products. A total of 78 VOCs were identified, with 42 common to both rapeseed and palm oil. An algorithm based on cosine similarity was proposed to group variables, resulting in six distinct emission clusters. The findings highlighted the prominence of saturated and unsaturated aldehydes, underscoring the role of fatty acid oxidation in shaping the frying fume composition. This study not only corroborates previous research but also provides new insights into VOC emissions during deep frying, particularly regarding the specific emission profiles of certain compound groups and the influence of frying conditions on these profiles. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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18 pages, 2104 KiB

Open AccessArticle

Integrating Epoxidation, High-Resolution Mass Spectrometry and Ultraviolet Spectroscopy to Unravel the Complex Profile of Boswellic Acids and Related Compounds in the Boswellia serrata Gum Resin Extract

by Andrea Castellaneta, Ilario Losito, Stefania Cometa, Francesco Busto, Elvira De Giglio and Tommaso R. I. Cataldi

Molecules 2024, 29(20), 4967; https://doi.org/10.3390/molecules29204967 - 21 Oct 2024

Viewed by 1057

Abstract

The chemical characterization of natural products is often a complex task that demands powerful analytical techniques. Liquid chromatography with high-resolution tandem mass spectrometry (HRMS/MS) is often employed, yet it can face hard challenges when isomeric species are present, and reference standards are lacking. [...] Read more.

The chemical characterization of natural products is often a complex task that demands powerful analytical techniques. Liquid chromatography with high-resolution tandem mass spectrometry (HRMS/MS) is often employed, yet it can face hard challenges when isomeric species are present, and reference standards are lacking. In such cases, the confidence level in compound identification can be significantly improved by the collection of orthogonal information on target analytes. In this work, 23 key compounds in Boswellia serrata extract (BSE), 12 of which correspond to boswellic acids (BAs) and 11 to triterpenoidic acid isomers, were identified by combining RPLC followed by serial UV and ESI(-)-FTMS and FTMS/MS detections with the evaluation of the reactivity towards C=C bond epoxidation with meta-chloroperoxybenzoic acid (m-CPBA), proposed as a fast chemical tool to gather information about C=C bond steric hindrance, a key structural feature of BAs and related compounds. The interpretation of UV spectra acquired after chromatographic separation corroborated the identification of the substitution patterns of enonic and dienic residues in ketoboswellic and dehydroboswellic acids. Moreover, MS/MS based on higher-energy collision-induced dissociation (HCD) unveiled new fragmentation pathways, providing important structural details on target analytes. The integrated approach developed during this study might pave the way for a deeper understanding of the BSE bioactive properties. Moreover, it can be considered an example of a more general strategy for the analysis of complex mixtures of natural compounds including also isomeric species. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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14 pages, 1659 KiB

Open AccessArticle

A New Activity Assay Method for Diamine Oxidase Based on Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

by Jan Strnad, Miroslav Soural and Marek Šebela

Molecules 2024, 29(20), 4878; https://doi.org/10.3390/molecules29204878 - 14 Oct 2024

Cited by 1 | Viewed by 1356

Abstract

Copper-containing diamine oxidases are ubiquitous enzymes that participate in many important biological processes. These processes include the regulation of cell growth and division, programmed cell death, and responses to environmental stressors. Natural substrates include, for example, putrescine, spermidine, and histamine. Enzymatic activity is [...] Read more.

Copper-containing diamine oxidases are ubiquitous enzymes that participate in many important biological processes. These processes include the regulation of cell growth and division, programmed cell death, and responses to environmental stressors. Natural substrates include, for example, putrescine, spermidine, and histamine. Enzymatic activity is typically assayed using spectrophotometric, electrochemical, or fluorometric methods. The aim of this study was to develop a method for measuring activity using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry based on the intensity ratio of product to product-plus-substrate signals in the reaction mixtures. For this purpose, an enzyme purified to homogeneity from pea (Pisum sativum) seedlings was used. The method employed α-cyano-4-hydroxycinnamic acid as a matrix with the addition of cetrimonium bromide. Product signal intensities with pure compounds were evaluated in the presence of equal substrate amounts to determine intensity correction factors for data processing calculations. The kinetic parameters k_cat and K_m for the oxidative deamination of selected substrates were determined. These results were compared to parallel measurements using an established spectrophotometric method, which involved a coupled reaction of horseradish peroxidase and guaiacol, and were discussed in the context of data from the literature and the BRENDA database. It was found that the method provides accurate results that are well comparable with parallel spectrophotometry. This method offers advantages such as low sample consumption, rapid serial measurements, and potential applicability in assays where colored substances interfere with spectrophotometry. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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15 pages, 2807 KiB

Open AccessArticle

Application of Fabric Phase Sorptive Extraction as a Green Method for the Analysis of 10 Anti-Diabetic Drugs in Environmental Water Samples

by Augosto Misolas, Mohamad Sleiman and Vasilios Sakkas

Molecules 2024, 29(20), 4834; https://doi.org/10.3390/molecules29204834 - 12 Oct 2024

Cited by 1 | Viewed by 1147

Abstract

Due to the increased prevalence of diabetes, the consumption of anti-diabetic drugs for its treatment has likewise increased. Metformin is an anti-diabetic drug that is commonly prescribed for patients with type 2 diabetes and has been frequently detected in surface water and wastewaters, [...] Read more.

Due to the increased prevalence of diabetes, the consumption of anti-diabetic drugs for its treatment has likewise increased. Metformin is an anti-diabetic drug that is commonly prescribed for patients with type 2 diabetes and has been frequently detected in surface water and wastewaters, thus representing an emerging contaminant. Metformin can be prescribed in combination with other classes of anti-diabetic drugs; however, these drugs are not sufficiently investigated in environmental samples. Fabric phase sorptive extraction (FPSE) has emerged as a simple and green method for the extraction of analytes in environmental samples. In this study, FPSE coupled with a high-performance liquid chromatography diode array detector (HPLC-DAD) was employed for the simultaneous analysis of different classes of anti-diabetic drugs (metformin, dapagliflozin, liraglutide, pioglitazone, gliclazide, glimepiride, glargine, repaglinide, sitagliptin, and vildagliptin) in environmental water samples. Four different fabric membranes were synthesized but the microfiber glass filter coated with sol-gel polyethylene glycol (PEG 300) was observed to be the best FPSE membrane. The parameters affecting the FPSE process were optimized using a combination of one-factor-at-a-time processes and the design of experiments. The FPSE was evaluated as a green extraction method, based on green sample preparation criteria. The FPSE-HPLC-DAD method achieved acceptable validation results and was applied for the simultaneous analysis of anti-diabetic drugs in surface and wastewater samples. Glimepiride was detected below the quantification limit in both lake and river water samples. Dapagliflozin, liraglutide, and glimepiride were detected at 69.0 ± 1.0 μg·L⁻¹, 71.9 ± 0.4 μg·L⁻¹, and 93.9 ± 1.3 μg·L⁻¹, respectively, in the city wastewater influent. Dapagliflozin and glimepiride were still detected below the quantification limit in city wastewater effluent. For the hospital wastewater influent, metformin and glimepiride were detected at 1158 ± 21 μg·L⁻¹ and 28 ± 0.8 μg·L⁻¹, respectively, while only metformin (392.6 ± 7.7 μg·L⁻¹) was detected in hospital wastewater effluent. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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15 pages, 6871 KiB

Open AccessArticle

A Trianalyte µPAD for Simultaneous Determination of Iron, Zinc, and Manganese Ions

by Barbara Rozbicka, Robert Koncki and Marta Fiedoruk-Pogrebniak

Molecules 2024, 29(20), 4805; https://doi.org/10.3390/molecules29204805 - 11 Oct 2024

Cited by 1 | Viewed by 849

Abstract

In this work, a microfluidic paper-based analytical device (µPAD) for simultaneous detection of Fe, Zn, and Mn ions using immobilized chromogenic reagents Ferene S, xylenol orange, and 1-(2-pyridylazo)-2-naphthol, respectively, is presented. As the effective recognition of analytes via respective chromogens takes place under [...] Read more.

In this work, a microfluidic paper-based analytical device (µPAD) for simultaneous detection of Fe, Zn, and Mn ions using immobilized chromogenic reagents Ferene S, xylenol orange, and 1-(2-pyridylazo)-2-naphthol, respectively, is presented. As the effective recognition of analytes via respective chromogens takes place under extremely different pH conditions, experiments reported in this publication are focused on optimization of the µPAD architecture allowing for the elimination of potential cross effects. The paper-based microfluidic device was fabricated using low-cost and well-reproducible wax-printing technology. For optical detection of color changes, an ordinary office scanner and self-made RGB-data processing program were applied. Optimized and stable over time, µPADs allow fast, selective, and reproducible multianalyte determinations at submillimolar levels of respective heavy metal ions, which was confirmed by results of the analysis of solutions mimicking real samples of wastewater. The presented concept of simultaneous determination of different analytes that required extremely different conditions for detection can be useful for the development of other multianalyte microfluidic paper-based devices in the µPAD format. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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21 pages, 5064 KiB

Open AccessArticle

Application of UHPLC-QqQ-MS/MS Method for Quantification of Beta-Adrenergic Blocking Agents (β-Blockers) in Human Postmortem Specimens

by Paweł Szpot, Kaja Tusiewicz, Olga Wachełko and Marcin Zawadzki

Molecules 2024, 29(19), 4585; https://doi.org/10.3390/molecules29194585 - 27 Sep 2024

Cited by 1 | Viewed by 1333

Abstract

Betablockers are one of the most frequently used medications in cardiology. They can lead to fatal drops in blood pressure and heart rhythm disturbances. Death is functional, and poisoning with this group of drugs can be difficult to detect. The liquid–liquid extraction (LLE) [...] Read more.

Betablockers are one of the most frequently used medications in cardiology. They can lead to fatal drops in blood pressure and heart rhythm disturbances. Death is functional, and poisoning with this group of drugs can be difficult to detect. The liquid–liquid extraction (LLE) method developed using ethyl acetate at pH 9 successfully identified 18 β-blockers in human blood. The method’s limit of quantification (LOQ) was in the range of 0.1 to 0.5 ng/mL. No carryover of substances between samples was detected, and no interfering ion current signals were observed in the biological samples at the retention times of the compounds or internal standards. All compounds had a coefficient of determination (R²) above 0.995. Intraday and interday precision (RSD%) and accuracy (RE%) for low and high QC levels were within 1.7–12.3% and −14.4 to 14.1%, respectively. Very good recovery (80.0–119.6%) and matrix effect (±20.0%) values were achieved for all compounds. In addition, fragmentation spectra were collected for all the examined substances, and high-resolution spectra were presented for landiolol and metipranolol, because they are not available in commercial HRMS spectra databases. The developed method was applied in authentic postmortem samples. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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14 pages, 2839 KiB

Open AccessArticle

Adsorptive Stripping Voltammetric Quercetin Determination in Pharmaceuticals and Urine Samples Using a Long Service-Life Array of Carbon Composite Microelectrodes

by Iwona Gęca and Mieczyslaw Korolczuk

Molecules 2024, 29(18), 4464; https://doi.org/10.3390/molecules29184464 - 20 Sep 2024

Viewed by 767

Abstract

This article presents for the first time a new working electrode with a long service life— the bismuth-plated array of carbon composite microelectrodes for the simple, fast and sensitive determination of quercetin by adsorptive stripping voltammetry. The main experimental conditions were selected. The [...] Read more.

This article presents for the first time a new working electrode with a long service life— the bismuth-plated array of carbon composite microelectrodes for the simple, fast and sensitive determination of quercetin by adsorptive stripping voltammetry. The main experimental conditions were selected. The calibration graph was linear from 1 × 10⁻⁹ to 2 × 10⁻⁸ mol L⁻¹ with an accumulation time of 60 s. The detection limit was equal to 4.8 × 10⁻¹⁰ mol L⁻¹. The relative standard deviation for 2 × 10⁻⁸ mol L⁻¹ of quercetin was 4.4% (n = 7). Possible interference effects resulting from the presence of other organic and surface active compounds and interfering ions were studied. The developed procedure was successfully applied to determine quercetin in pharmaceutical preparations and the spiked urine samples. Full article

(This article belongs to the Special Issue Analytical Chemistry in Europe: Towards Sustainability and Quality of Life, 2nd Edition)

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