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The development of rapid chromatographic procedures is of utmost relevance to analytical laboratories since the modern pharmaceutical business is continually developing faster and more precise methods of drug discovery, development, distribution, and monitoring. Comprehensive two-dimensional (2D) chromatography is being developed as a tool to address challenges in the analysis of complex materials. Complex sample analyses may yield data that is challenging to quickly and accurately process. Here, chemometric analysis of data has shown to be the most fruitful and illuminating method. There are several applications for the determination of organic chemicals in samples with varying matrices. Gas/liquid chromatographic techniques are used for the bulk of organic chemical determinations. Therefore, it is crucial that these processes have minimal effects on the natural world. The collection and processing of samples, chromatographic separation, and final determination might all have less environmental impact if chromatographic methods were used. In both GC and LC, multidimensional separation methods may be used to improve the environmental friendliness of the analysis. The study describes 2D chromatographic techniques for GC-MS, 2D-LC, 2D-GC, 2D-CE, FTIR, and 2D-IR. Moreover, their advantages, challenges, and previous analytical data are also covered. [ABSTRACT FROM AUTHOR]

A rapid procedure for the determination of phenol and cresol isomers in drinking, sea, and polluted domestic wastewater is developed based on a single-stage extraction of analytes by extractive freezing-out under sample centrifugation conditions. In combination with gas chromatography, the procedure provides the minimum detection limits for each of phenols in 10 mL of water at a level of 0.0005 µg/mL. The duration of sample preparation does not exceed 30 min; the consumption of the ethoxyethane extractant is 1.4 mL. In comparison with liquid–liquid and solid-phase extraction traditionally used at the stage of sample preparation, the proposed procedure is simpler and more environmentally friendly. The stages of filtering samples and dehydrating extracts are excluded; the amount of chemical glassware is minimized. [ABSTRACT FROM AUTHOR]

This review is devoted to the consideration of prospects and directions for the development of methods and approaches to the analysis of high-purity industrial gases and volatile hydrides, chlorides, fluorides, and organoelement compounds with natural and isotopically enriched compositions. The currently known capabilities for the determination of impurities in them using mass spectrometry, IR spectroscopy, gas chromatography, and chromatography–mass spectrometry are analyzed. [ABSTRACT FROM AUTHOR]

Luminescent quantum dots (QDs) of I–III–VI2 semiconductors present a new class of luminescence materials that combine unique optical and electronic properties while exhibiting low toxicity compared to conventional cadmium-based QDs. Advances in the colloidal synthesis of ternary QDs have been used to develop fluorescence chemical and biological sensors for the detection of various analytes. The review covers the main approaches to synthesizing QDs of the I–III–VI2 structure, the features of their structure and properties, and current trends in their use as low-toxic luminescent labels in biomedicine and chemical analysis. [ABSTRACT FROM AUTHOR]

We substantiate an approach to the creation of a device for establishing gross adulteration of gasoline by replacing their part with fuel with a lower octane number and demonstrate the application of mass-sensitive sensor electrodes using the specific features of the adsorption of volatile compounds from the headspace of gasoline with different octane numbers (AI-92, AI-95) by the sensor modifiers. The results helped select three coatings most sensitive and selective to traces, differently adsorbing compounds of the highly volatile gasoline fraction. Simple recorded and calculated signals of the "electronic nose" SΣ, Sτ, A(i/j), AS(τ1/τ2), giving information on the composition of a gasoline sample and assessing the change in composition on adding fuel of a different type or brand, are proposed. The algorithm for calculating and making a decision is simple and can be programmed into the microcircuit of a mobile device. Introducing an "electronic nose" gas analyzer based on piezoelectric balances into the fuel quality control system is helpful to reveal the facts of adulteration of high-octane gasoline by adding gasoline with a lower octane number and to estimate the amount of the additive. A method is developed for in situ analysis performed by experts or untrained users; it readily gives an assessment of adulteration with an additive concentration of 6 to 50 vol % with an error of no more than 12%. [ABSTRACT FROM AUTHOR]

We demonstrated a possibility of using a chemical sensor array for the control of the formation of the aroma of confectionery masses during conching. The correlation between the results of sensor-metric analysis and physical and chemical indicators of the quality of confectionery masses was evaluated. An array of chemical sensors enables the assessment of the intensity and shift of the composition of the aroma during conching as the key stage of production. It ensures a rapid assessment of standard indicators, that is, the acid number of lauric substitute for cocoa butter by the signal of the sensor with polyethylene glycol adipate (Pearson's correlation degree R = 0.94), the acidity of confectionery masses of different nature by the signals of sensors based on crown ether and Tween-40 (R = 0.90–0.92). The most valuable achievement is the ability of controlling the decrease in the concentration of nonvolatile compounds and the total concentration of sugars and reducing sugars during conching, based on the signals from two sensors (R = 0.90–0.93). We also show a possibility of introducing an electronic nose gas analyzer based on adsorption-type sensors into the control system of confectionery production for determining physical and chemical parameters and digitizing the most unstable property, that is, aroma, compliance and optimization of recipes, an objective and reproducible assessment of the quality of raw materials and confectionery products, and the control of the reproducibility of the integral indicator (aroma) for different batches of finished products. [ABSTRACT FROM AUTHOR]

Luminescence semiconductor quantum dots (QDs) offer a rather new type of luminescent labels used for the visual and instrumental determination of analytes in various versions of chemical analysis. The high quantum yield, photostability, narrow emission spectra, and wide excitation regions of these species make them ideal labels for analysis and ensure the development of procedures for the simultaneous determination of several substances and the attainment of low limits of detection. The widespread introduction of QDs in analytical practice is limited by the multistage character and laboriousness of some approaches to the synthesis of QDs and reagents on their basis, their trend to nonspecific interactions, and a probability of fluorescence reabsorption at the improper selection of the concentration of QDs. The review covers the main approaches to the synthesis, modification, and use of luminescence QDs in chemical analysis. Approaches to the sensitization and multiplicity of analysis and methods for regulating selectivity based on both the properties of QDs and, in addition, the receptors used are discussed. [ABSTRACT FROM AUTHOR]

We considered the physicochemical regularities and analytical capabilities of separation methods based on the manifestation of capillary effects in hydrophobic microporous media, namely, liquid–gas chromatography with a stationary gas phase in the pores of a solid-phase substrate and a mass-exchange process in liquid–gas and liquid–liquid systems, carried out in a biporous matrix. The advantages of these methods compared to conventional mass-exchange processes in the same systems in terms of higher efficiency and a possibility of the separation of substances in a continuous mode are shown. [ABSTRACT FROM AUTHOR]

The basic regularities of an acid retardation method for the chromatographic separation of mixtures in concentrated acidic solutions and its new versions, which are convenient for use in technology and chemical analysis, developed by the authors are described. The results of studies on the application of a new approach to the separation of electrolyte mixtures with the use of columns in which an anion exchanger bed was filled with an organic liquid immiscible with water and aqueous solutions are presented. With the use of the separation of the components of model mixtures containing nitric acid and its salts, the natural solutions of the acid decomposition of bone tissue, and soil on the AV-17 anion exchanger in nitrate form as examples, it is demonstrated that the approach proposed is promising for sample preparation in chemical analysis, in particular, for effectively reducing the acidity of solutions after the digestion of difficult-to-decompose samples. The reproducibility of the results obtained using this approach was evaluated by analyzing the elution curves of the sorption–desorption of the macrocomponents of bone mineralization solution in repeated experiments. [ABSTRACT FROM AUTHOR]

The review summarizes authors' works of the last 15 year covering the possibilities, advantages, and prospects for the use of optical sensors based on peroxidase for the determination of a wide range of biologically active compounds, i.e., phenolic compounds and hydroperoxides of different structures, phenothiazines, catecholamines, and their metabolites, for the quality control of drugs, foodstuffs, biomedical research, and clinical diagnostics. [ABSTRACT FROM AUTHOR]

A pneumovacuum circuit of a Tsvet-800-2 gas chromatograph with a helium ionization detector (HID) in the ionization amplification mode is proposed for controlling limiting trace impurities in ammonia, arsine, monosilane, and phosphine of grade 6N4. The conditions for the preparation and reliable operation of the chromatograph with the HID are systematized. The effect of an additive of (0.0-17.6) × 10 mol % of hydrogen in the carrier gas of the detector on the polarity of its signal on the impurities of oxygen and nitrogen at a level of (0.5-20.0) × 10 mol % is studied. Methods are proposed for eliminating systematic errors in the determination of the concentration of oxygen and nitrogen in the range from 0.5 × 10 to 1 × 10 mol % in 6N4 volatile hydrides, caused by 'counter' impurities in the carrier gas, the mechanism of the heteropolar sensitivity of the HID, and irreversible chemical reactions of oxygen traces with phosphine and products of its decomposition on a CaA-ShM zeolite in a separating column of a chromatograph. Gas chromatography analysis of ammonia, arsine, monosilane, and phosphine of grade 6N4 was carried out. [ABSTRACT FROM AUTHOR]

The problem of the decomposition of additive spectra of mixtures of the known qualitative composition into components is considered. An algorithm for the determination of component concentrations in such mixtures is proposed based on the representation of spectral curves of different nature by polynomials. The algorithm ensures the search for a solution in the case when the initial information on the spectra of components is presented by fuzzy sets. The workability of the approach is tested in big series of computer experiments using IR spectra of quinary mixtures of organic substances as examples. [ABSTRACT FROM AUTHOR]