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Various methods have been studied for the extraction of polychlorophenols from bottom sediments for the subsequent gas-chromatographic determination as monochloroacetic acid esters, i.e., extraction with toluene and dichloromethane after the dehydration of the matrix, extraction with isopropanol without dehydration on mechanical shaking, sonication, and in a Soxhlet apparatus. It has been found that the recovery depends on the method of treatment of bottom sediment samples, the RSD value did not exceed 10-20%. The recovery in the extraction with toluene on mechanical shaking or sonication was 70-80%. The limits of detection for polychlorophenols were 1-3 ng/g calculated for a dry weight. Keywords: polychlorophenols, bottom sediments, extraction, gas--liquid chromatography, derivatization, monochloroacetic acid anhydride DOI: 10.1134/S1061934815080031, INTRODUCTION Phenol and its derivatives have long been among the main objects of environmental monitoring. Polychlorophenols are high in the list of priority organic pollutants of natural waters, which is [...]

Phenyl and p-bromophenyl substituted 1H,2H,3H,4H-pyrido[4,3-d]pyrimidinium diiodobromides have been identified and determined by capillary zone electrophoresis on an unmodified quartz capillary It has been found that an increase in the number of bromine atoms in the structure of 1H,2H,3H,4H-pyrido [4,3-d]pyrimidinium derivatives consecutively decreases the electrophoretic mobility of the cations. The developed method makes possible the determination pyrido [4,3-d]pyrimidiuum derivatives in the concentration range (0.03-0.25) mM with the [c.sub.mln](3.1-10.0) µM. Keywords: 1H,2H,3H,4H-pyrido [4,3-d]pyrimidinium derivatives, capillary zone electrophoresis DOI: 10.1134/S1061934813110063, INTRODUCTION Heterocyclic compounds based on pyridopyrimidine are widely spread because of their high biological activity and use in pharmaceutical chemistry [1]. The pyridine ring is part of the structure of [...]

A procedure was developed for the determination of the following thioamides based on thiazole, 1,3,4-thiadiazole, 1,2,4-triazole, and tetrazole: 2-mercaptothiazole (I), 2-mercapto-1,3,4-thiadiazole (II), 2-mercapto-5-methyl-1,3,4-thiadiazole (III), 3-mercapto-1,2,4-triazole (IV), 3-mercapto-4-methyl-I, 2,4-triazole (V), and 5-mercapto-1-methyltetrazole (VI). The determination was performed by reversed-phase HPLC on a column (150 x 4 mm) packed with Diaspher-110-C18 (5 µm) using elution with an acetonitrile-acetate buffer solution (pH 4.70) mixture (5 : 95). Detection was performed at the light absorption maximums of compounds I (320 nm), II (305 nm), III (310 nm), IV (260 nm), V (254 nm), and VI (245 nm). The calibration graphs were linear over the following concentration ranges (µg/mL): 0.47-11.72 (I), 0.47-II. 82 (II), 0.53-13.22 (III), 0.40-10.11 (IV), 0.46-11.52 (V), and 0.46-11.62 (VI). The limits of detection were 0.45, 0.43, 0.50, 0.37, 0.41, and 0.42 µg/mL for compounds I-VI, respectively. Conditions for the separation of a mixture of compounds I and III-V and for the quantitative determination of compounds I-VI by capillary zone electrophoresis (CZE) were optimized. CZE was performed on a quartz capillary of size 60 cm (effective length of 50 cm) x 75 µm at a voltage of 20 kV with a borate buffer solution (pH 9.18). The procedure allowed us to evaluate the concentrations of substances in the ranges of 1.17-93.75 (I), 1.18-94.54 (II), 1.32-105.76 (III), 1.01-101.13 (IV) 1.15-115.16 (V), and 1.16-116.15 (VI) µg/mL with the detection limits of 1.10, 1.11, 1.20, 0.96, 1.01, and 1.02 µg/mL for compounds I-VI, respectively. Keywords: heteroaromatic thioamides, HPLC, capillary zone electrophoresis DOI: 10.1134/S1061934811010023, Heteroaromatic thioamides (based on imidazole, thiazole, and uracil) belong to essential heterocyclic systems that regulate thyroid function in thyrotoxicosis, Graves' disease, etc. [1]. The area of practical applications of thiones [...]

A selective and highly selective procedure is presented for the determination of the systematic class of polychlorophenols (PCP) by gas chromatography with electron capture detection (ECD) upon derivatization with monochloroacetic anhydride. The relative intensity of the analytical signal (in comparison to simple acetates) is increased 8-9 times for dichlorophenols and 2.5-4 times for trichlorophenols; for tetra- and pentochlorophenols, the enhancement coefficient is 1.5-2. The stage of PCP derivatization is studied by GC/MS; the mass spectra of tri- and tetrachlorophenol monochloroacetates were recorded for the first time. The limits of determination were 0.005-0.016 µg/L (RSD 6-7%), and the upper limit of the detected concentrations was 0.050-0.160 µg/L (RSD 3-4%). Key words: gas chromatography, polychlorophenols, monochloroacetic anhydride DOI: 10.1134/S1061934810100060, Chlorinated phenol derivatives are highly toxic xenobiotics; their concentration of in environmental objects is to be controlled. Di- and polychlorophenols (PCP) appear the most toxic [1, 2]. The maximal acceptable [...]

Abstract -- Diiodobromides of P-containing organic cations, 3-carboxypropyltriphenylphosphonium (I) and tetraphenylphosphonium(II), were identified and quantitatively determined by capillary electrophoresis using an unmodified fused-silica capillary. The procedure for the quantitative determination [...]