Journal of Analytical Chemistry最新文献

One of the most valuable raw materials in the coffee industry is green coffee, especially the Coffea arabica variety, which is preferred by roasters and coffee makers. This study aimed to identify flavor precursors in green coffee beans using various analytical techniques, including counter-current chromatography, liquid chromatography, and methods such as high-resolution gas chromatography coupled with mass spectrometry, high-performance liquid chromatography-electrospray mass spectrometry, and one- and two-dimensional nuclear magnetic resonance spectrometry (NMR). Ten flavor precursors were discovered in this study, including two linalool oxides (furanoid E-Z) disaccharides, linalool, and 4-vinyl guaiacol. The intact glycosides were analyzed using dimensional NMR, and two different substances, methyl-α/β-L-arabinofuranose and methyl-α/β-L-arabinopyranose, were identified. These findings can assist in verifying the authenticity of green coffee.

Potential of a simple and an available method for identifying and authenticating edible vegetable oils using digital colorimetry, Fourier-transform spectrometry in the near and middle IR spectral regions, and chemometric processing of the analysis results is shown. Identification by the type of oil (mustard, linseed, corn, olive, and sunflower) and authentication (authenticity and falsification) are carried out by the intrinsic color of vegetable oils and fluorescence upon irradiating samples with monochromatic light in the UV, visible, and IR regions (365, 390, 470, 565, 700, 850, 880, 940 nm, and 400−10 000 cm⁻¹). A device and a method for measuring colorimetric parameters using a smartphone and data processing using the RGBer, PhotoMetrix PRO^®, XLSTAT and The Unscrambler X specialized software are proposed. The use of chemometric analysis made it possible to establish the authenticity of vegetable oils and identify facts of falsification by diluting expensive oils with cheaper ones.

Toxic mushrooms can be classified into various groups based on the components they contain: cyclopeptides, gyromitrin, muscarine, isoxazoles (muscimol, ibotenic acid), orellanine, psilocybin, and gastrointestinal irritants. Mushrooms containing cyclopeptides are the most toxic species worldwide, responsible for 90–95% of human fatalities. Rapid and accurate identification of toxins in mushrooms and biological samples is critical for diagnosing and treating mushroom poisoning. Methods for detecting toxins are essential for ensuring timely treatment. This review analyzes scientific literature on the detection of mushroom toxins in fungal and biological samples. Particular attention is given to chromatographic methods, especially high-performance liquid chromatography coupled with mass spectrometry.

A method is proposed for determining 2,4-dichlorophenoxyacetic acid (2,4-D) and its metabolite, 2,4-dichlorophenol (2,4-DCP), in soils. 2,4-D and 2,4-DCP are isolated from soil by extraction with an alkali solution. The analytes are extracted from the extract using a sorbent based on magnetite nanoparticles and carbon obtained by burning rice husk, and desorbed with methanol. In the resulting concentrate, 2,4-D and 2,4-DCP are converted into methyl esters and determined by GC–MS. The limits of detection for 2,4-D and 2,4-DCP are 3.0 and 0.08 μg/kg, respectively. Leached chernozem (border of Stavropol and Krasnodar Krais) is chosen as a real soil for analyzing the distribution of the Ballerina herbicide (2,4-D ethylhexyl ester) and its degradation product. One day after the herbicide application, the concentration of 2,4-D in the surface soil layer is 119 μg/kg. Precipitation has a significant effect on the movement of 2,4-D along the soil profile. The greatest decrease in the concentration of 2,4-D is found between 3 and 10 days after the herbicide application. One month after the herbicide application, the 2,4-D concentrations are 31, 18, and 11 μg/kg at depths of 10, 30, and 50 cm, respectively; 2,4-D is not detected in the surface soil layer. 2,4-DCP is present in detectable quantities on the 16th day after the herbicide application; its degradation is significantly slower than that of 2,4-D. After 1.5 months, the 2,4-DCP concentrations are 0.53, 0.45, and 0.22 μg/kg at the depths 10, 30, and 50 cm, respectively. During the same period, 2,4-D is not detected throughout the soil profile.

Multicomponent analysis of residual veterinary drugs by HPLC–MS/MS is relevant for ensuring food safety. A significant problem is the determination of veterinary drugs with large molecules. Electrospray ionization of such molecules is difficult, and it is difficult to achieve the required sensitivity by classical isolation from the matrix with subsequent detection. Such drugs include avilamycin and nosiheptide. This problem can be solved by the fragmentation of molecules into smaller, more easily detectable residues by hydrolysis, which, in turn, poses the task of optimizing the conditions for such preparation, as well as assessing the uniqueness of the selected marker. A possibility of the simultaneous determination of avilamycin and nosiheptide in chicken meat by their alkaline hydrolysis to markers, dichloroisoverninic acid and 4-hydroxymethyl-3-methylindole-2-carboxylic acid, respectively, is shown. The conditions of extraction, hydrolysis, and methods of further purification are studied. Under the selected conditions, the recovery of analytes was >85%; in addition, satisfactory reproducibility (RSD ≤ 15%) was achieved. The limits of detection were 5 μg/kg. The developed procedure is highly selective, rapid, easy to implement, and inexpensive and has good analytical characteristics.

This study compares two sample preparation procedures—liquid–liquid extraction using a nonpolar solvent and solid-phase extraction—for analyzing decomposed biological tissues from cadavers changed due to decomposition. The research aimed to develop a rapid and a straightforward method for sample preparation to determine carfentanil in decomposed tissue samples. A gas chromatography–mass spectrometry (GC–MS) analysis was performed using an Agilent 7820/5975 Maestro chromatograph with a Rxi-5ms mass-selective detector (Restek). For a liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis, a Shimadzu 8050 triple quadrupole mass spectrometer detector was employed. Chromatographic separation was conducted in a reversed-phase adsorbent column (Phenomenex Kinetex C18). Liver homogenates were selected as the primary research material, with lysis products derived from freezing and thawing liver tissue samples used as an alternative. Sample preparation of the homogenates was conducted by liquid–liquid extraction with heptane and solid-phase extraction. The results indicate that fluids containing lysis products offer the optimal choice for rapid and efficient sample preparation. The analytical signal of the target substances was 1.5–2 times higher in the lysis-derived samples compared to the tissue homogenates, regardless of whether solid-phase or liquid–liquid extraction methods were employed.

The determination of volatile organic compounds (VOCs) in various gases, including atmospheric and exhaled air, is necessary to solve a wide range of environmental problems and monitore gas composition, and is increasingly used for diagnosing a variety of diseases. Recently, methods of soft ionization with minimal fragmentation of components have been rapidly developed. Our research group is developing an approach to the direct analysis of mixtures of volatile organic compounds by time-of-flight mass spectrometry with a pulsed glow discharge. Previously, the effects of various gases and gas mixtures on ionization processes have not been compared. This work presents a study of the mechanisms of VOC ionization in argon, nitrogen, and air. Toluene, p-xylene, chlorobenzene, and 1,2,4-trimethylbenzene were selected as model VOCs. The parameters of the microsecond pulsed glow discharge (pulse period and duration, ejection pulse delay, pressure in the discharge cell) have been optimized for each compound and a gas mixture of several volatile organic compounds. The predominant ionization mechanisms are the formation of molecular ions of VOCs through Penning ionization and proton transfer reactions, with their effects varying depending on the gas. The use of argon, even with a small addition of water, leads to the predominance of the proton transfer reaction, while in nitrogen and air mixtures, Penning ionization prevails. Under the optimized conditions in air, for which the highest VOC intensities were attained, the developed approach for analyzing exhaled breaths and samples of atmospheric air was tested.

Neurodegenerative diseases form a group of nervous system disorders characterized by a prolonged latent stage, a wide range of manifestations linked to the heterogeneity of symptoms, varying levels of disease aggressiveness, and progressive neuronal death. Clinical data, alongside expensive invasive and noninvasive imaging techniques, primarily form a basis for diagnosing neurodegenerative diseases. There is no specific laboratory test available for their diagnosis. Exhaled breath represents a bodily secretion, and its collection is both simple and cost-effective. The analysis of exhaled gases is an inexpensive and a noninvasive method for detecting a wide range of diseases, including neurodegenerative disorders. Molecular profiles of volatile organic compounds in an exhaled breath, relevant for diagnosing various neurodegenerative diseases, can be obtained through human breath analysis using an “electronic nose.” Identifying volatile organic compounds and utilizing them as specific biomarkers for neurodegenerative diseases offers a precise, reproducible, and rapid diagnostic alternative to conventional invasive methods. This review focuses on the challenges and achievements of the last decade (2014–2023) in applying the electronic nose technology to the detection and identification of potential volatile organic compounds associated with neurodegenerative processes. It highlights studies on the detection of potential volatile organic compounds in the exhaled breath of patients with Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and amyotrophic lateral sclerosis using an electronic nose and gas chromatography–mass spectrometry. The review discusses trends in the development and application of the electronic nose technology to medical care, enabling the precise and sensitive detection of key volatile organic compounds in an exhaled breath.

Gold nanoclusters (AuNCs) are of great interest due to their intense size-dependent luminescence, large Stokes shift, photostability, and biocompatibility. In this work, bovine serum albumin stabilized AuNCs were successfully synthesized using a one-step synthesis at atmospheric pressure. The influence of the precursor ratio on the optical properties of AuNCs was assessed. The possibility of detecting the anticancer drug doxorubicin due to static quenching of AuNC luminescence was demonstrated. The detection limit for doxorubicin was determined to be 7 μM. The applicability of the developed nanosensor for the detection of doxorubicin in human blood plasma corresponds to a high recovery of 94‒98% and a standard deviation of less than 15%. The proposed approach for the determination of doxorubicin using the developed luminescent nanosensor without the use of additional linkers, reagents, or preparation steps is a promising initiative for monitoring anticancer drugs in human biofluids. This will allow the medical treatment protocol to be adjusted to reduce the negative impact of doxorubicin on the patient’s health.