Journal of Analytical Chemistry最新文献

A capillary electrophoresis technology for determining synthetic polyphosphates (SPs) in meat products (MPs) has been developed and implemented. The SP content was monitored in filtered MP extracts. Extraction and separation modes were developed, and the geometric parameters of the capillary and SP detection were selected. It is proven that the content of tri- and diphosphates of MPs decreases differently over time (the content of triphosphates decreases faster than that of diphosphates at the same temperature) and depends on both the MP storage temperature and the technological processes during MP production.

This review considers the outcomes of two decades of the development of the technique of extractive freezing-out. The method introduces a novel extraction principle based on the low-temperature separation of the target analytes through the redistribution of the solutes between the liquid phase of a pre-added, nonfreezing hydrophilic solvent and the solid phase of ice formed during the freezing process. A significant advancement of the method resulted from the implementation of extractive freezing-out under centrifugal force conditions (EFC). The introduction of EFC as a sample preparation step into numerous protocols for the determination of organic compounds has enabled the successful application of the method to chemical toxicological analysis, food quality control, environmental monitoring, and hydrochemical investigations. The technique demonstrates clear advantages over conventional liquid–liquid extraction, headspace analysis, and solid-phase extraction. The immediate prospects for the further development of the method are noted.

A method is proposed for reducing the limit of detection for p-aminobenzoic acid and some of its medicinal derivatives in condensation reactions with p-dimethylaminobenzaldehyde, based on a combination of catalysis by anionic (effect of “micellar catalysis”) and preconcentration by non-ionic surfactants (effect of “micellar microextraction”). The conditions for obtaining saturated micellar phases of Triton X-114 in the absence and in presence of sodium dodecyl sulfate (SDS) ions and micelles, reactants, and salting-out agents (NaCl, Na₂SO₄, Na₃C₆H₅O₇) are optimized. Micellar-saturated phases of Triton X-114 and SDS are proposed as test means, ensuring the effective preconcentration of the analytical forms of Schiff bases of the studied analytes and their determination at the nanogram level in aqueous media, blood plasma model, and dosage forms at concentrations of an order of n × 10^–8 M by colorimetric methods using digital technologies.

Yerba mate (Ilex paraguariensis) is a native South American plant widely recognized for its high content of polyphenols, particularly caffeoylquinic acids. During the industrial processing of yerba mate, by-products such as discarded leaves and branches are generated, providing low-cost alternatives for polyphenol extraction. The aim of this study was to validate a high-performance liquid chromatography method with diode array detection for the determination of the major polyphenols in yerba mate by-products, specifically six caffeoylquinic acids and the flavonoid rutin. The method was validated by assessing its linearity, detection and quantification limits, and repeatability, confirming its suitability for the analysis of yerba mate by-products extracts. The validated method was applied to the analysis of by-products from different yerba mate manufacturers. Quantitative analysis revealed significant differences in polyphenolic profiles and concentrations between leaves and branches. In leaf residue extracts, 3-caffeoylquinic acid was the most abundant polyphenol, whereas 5-caffeoylquinic acid was predominant in branches. These findings highlight the potential of yerba mate processing residues as low-cost sources of polyphenols, supporting the valorization of these by-products.

Procedures for the determination of 53 impurities, including rare earth elements, in boric acid by inductively coupled plasma optical emission spectrometry (ICP–OES) have been developed. To optimize analysis conditions, the variation of impurity element signals was studied at boron concentrations ranging from 0 to 5000 mg/L and plasma powers of 1000, 1300, and 1600 W under axial observation. Most impurity elements exhibited the maximum analytical signals at the highest plasma power and at the highest boron concentration in the test solution. Taking into account the significant effect of the matrix on impurity element signals starting from approximately 500 mg/L of the matrix element, calibration curves were constructed using the spike method. The accuracy of the analysis was confirmed by spiking with the analyte elements with recoveries of 85–115%. The limits of detection calculated by the 2s test ranged from n × 10^–7 to n × 10^–4 wt %.

This study presents the development of a novel electrochemical sensor for the determination of erlotinib (ERT), a non-small cell lung cancer drug, using a modified glassy carbon electrode composed of p-type cuprous delafossite CuBO₂ nanosheets and graphene quantum dots. The CuBO₂ was synthesized via a hydrothermal method and characterized using X-ray diffraction and scanning electron microscopy. The modified electrode exhibited enhanced electrocatalytic activity towards ERT oxidation, which caused a significant increase in oxidation current and shifted the oxidation potential to more negative values. The sensor demonstrated a linear response to ERT concentrations ranging from 1.0 to 60.0 µmol/L, with a detection limit of 0.5 µmol/L. The electrode also showed excellent stability, reproducibility, and selectivity, making it suitable for real sample analysis. The proposed method was successfully applied to determine ERT in human serum samples.

Chaihu-Qingdai Decoction (CHQDD) has been widely used in China to clear liver-fire, and its monarch drugs are Chaihu and Qingdai. However, the current research on the material basis of the medicinal effect of CHQDD is unclear, which limits its further research. In this study, an ultra-high performance liquid chromatography combined with mass spectrometry was proposed for the quality control of CHQDD based on the qualitative and quantitative analysis of 13 active ingredients (saikosaponin A, saikosaponin D, indigo, indirubin, tryptanthrin, berberine, gardenoside, liquiritin, glycyrrhizic acid, glycyrrhetinic acid, ferulic acid, hesperidin, and luteolin), the index component of each single herb. In addition, a comprehensive comparative analysis method of CHQDD and its monarch drug decoction was established to analyze the variations in active components before and after compatibility. The results show that 13 major constituents were identified and determined in CHQDD. The content of indirubin, tryptanthrin, and saikosaponin D in CHQDD is significantly higher than the Chaihu or Qindai decoction, while the content of indigo in CHQDD is decreased compared with the Qindai decoction. This study successfully identified the quality features of CHQDD, which can serve as a reference for further clinical application of CHQDD. Consequently, this strategy provides a valuable reference for the exploration of traditional Chinese medicine formula compatibility.

Present-day optical spectroscopy successfully solves problems of the quantitative and qualitative analysis of multicomponent mixtures of complex chemical and morphological composition. Many natural and man-made samples require direct analysis without separation into components or complex sample preparation, and often without a possibility of physical sampling. This has become possible due to technical improvements in the analytical equipment, on the one hand, and the development of mathematical methods for the analysis of multivariate data (chemometrics), on the other hand. This review considers of the most important chemometric algorithms from the viewpoint of their contributions to the creation and development of methods for the analysis of multicomponent mixtures by optical spectroscopy. Emphasis is placed on molecular spectroscopy in the ultraviolet, visible, and infrared regions, in which the accuracy and stability of the results of analysis largely depend on the mathematical apparatus used because of significant overlapping of absorption (emission) bands. Fundamental theoretical information providing a key to understanding the efficiency of the discussed methods and algorithms in constructing models for the calibration, classification, and exploratory analysis of multivariate data is also presented. Some of the presented information is reflected in the Russian scientific periodicals for the first time. Examples illustrating the use of optical spectroscopy and chemometrics for solving real analytical problems in the chemical, food, and pharmaceutical industries, ecology, and medicine without sample preparation are presented.

A procedure is developed for preparing a selective bioinorganic adsorbent based on silicon dioxide particles modified with an imprinted protein (IPs). Bovine serum albumin served as the matrix protein molecule. The imprinting process was carried out in the presence of several template molecules—coumarin, 4-hydroxycoumarin, quercetin, and 5,7-dimethoxycoumarin—which acted as dummy templates of the mycotoxin ZEN. To pre-evaluate the feasibility of replacing ZEN with dummy templates and to determine the optimal concentration of the template molecules for IP synthesis, methods of computational chemistry were used, including molecular docking and molecular dynamics. Surface premodification of silicon dioxide particles proved essential for synthesizing IP-based sorbents. The resulting bioinorganic adsorbents demonstrated ability of extracting template molecules through solid-phase extraction from model solutions: coumarin (Q = 2.0 mg/g), 4-hydroxycoumarin (Q = 1.2 mg/g), quercetin (Q = 0.8 mg/g), 5,7-dimethoxycoumarin (Q = 2.2 mg/g), and ZEN from a wheat extract (Q = 4.79 mg/g, IF = 2.45). Zearalenone adsorption isotherms were constructed for IP-modified sorbents synthesized using different dummy templates. The cytotoxicity of the IPs was studied and their biosafety was assessed using the AGREEMIP tool.

Currently, most online monitors available on the market to detect the total chromium (TCr) in water mostly employ potassium permanganate or potassium persulfate oxidation-1,5-diphenylcarbazide (DPC) spectrophotometry. However, some problems still exist, such as the interference of residual oxidants with the determination, high temperature and time-consuming oxidation digestion reaction, high consumption of multiple chemical reagents, and complicated operation. Thereby, this study proposed a novel method combining ozone-based advanced oxidation processes with DPC spectrophotometry for the rapid and environmentally friendly determination of TCr in water. Based on a novel experimental device designed for the determination of TCr, the effects of reaction solution volume, pH, reaction time, ozone flow, and ultraviolet light intensity on the oxidation rate of TCr were investigated. Concurrently, the influence of the solvent of the chromogenic agent, chromogenic acidity, amount of chromogenic agent, and chromogenic time on the determination outcomes of TCr were also explored and optimized. Results revealed that under the optimized process conditions, within the concentration range of 0–1.25 mg/L, the proposed method manifested outstanding linearity (R² = 0.9998), precision, indication error, method detection limit, and conversion rate were 1.14, 1.17%, 0.0007 mg/L, and 98.99%, respectively. This will be a promising and alternative method for routine analysis or online monitoring of TCr in water.