The way of definition of formaldehyde in water by the method of high performance liquid chromatography (HPLC) with the use of solid-phase extraction for concoction and extraction of the analyzed derivative formaldehyde is presented. The method is distinguished by the simplified and accelerated procedure of the sample preparation in comparison with classical liquid extraction. Chromatographic division of substances was reached on the turned phase column C18 with the use of mixture of the deionized water and an acetonitrile as a mobile phase. Definition was carried out at absorption wavelength of 360 nanometers. Linearity was reached in the ranges of concentration from 1 to 200 mcg/l. Full validation of a method is carried out. For control samples of all levels, including the lower limit of quantitative definition, the value of repeatability (RSD) accounted for ≤15%. The index of the accuracy amounted to ≤10%. The presented way showed good validation characteristics and can be recommended for the simplification and acceleration of the determination of the content of formaldehyde in water by the HPLC method

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Objective of research: Development of methods for the determination of fenbendazole and its metabolites in milk by liquid chromatography coupled with tandem mass spectrometry. Materials and methods: Fenbendazole was administered orally to five cows. Samples of milk were taken on 1, 3, 5 and 10 days of drug application. The research method includes a description of reagents, plates and equipment; mass-spectrometric conditions for analysis of fenbendazole and its metabolites; preparation of the equipment to operation; preparation of eluent solution; preparation of the chromatograph to analysis; determination of chromatographic parameters of standard drug samples; preparation of milk samples to analysis; establishment of parameters of extracts’ chromatography; procedure of calibration of fenbendazole and its metabolites in eluent. Results and discussion: When studying the pharmacokinetics of fenbendazole and its metabolites (sulfone and sulfoxide) in milk, it was found that the maximal concentrations were determined 24 h after drug administration and were 22,6 ng/ml for fenbendazole sulfone, 34,0 ng/ml for fenbendazole sulfoxide and 19,7 ng/ml for fenbendazole. 10 days after treatment, the concentrations of fenbendazole and its metabolites in milk did not exceed permitted values.

Introduction. The modern highly sensitive methods of controlling substances that affect humans in real environmental conditions are necessary to adequately assess the quality and chemical safety of drinking water, including pesticides used in agriculture for the destruction of weeds and pests. The aim of the work was to improve the sensitivity of existing techniques for the determination of triazine pesticides in their joint presence to control drinking and bottled water. Material and methods. The studies were performed using a chromatography mass-spectrometric system including a liquid chromatography with tandem mass-spectrometric triple quadrupole detector. Results. The influence of various factors on the extraction of triazine pesticides from water has been studied, the chromatographic and detection conditions have been optimized. Linearity in the range of 0.1 - 10 μg / dm3 is proved. The limits of detection and quantitative determination of triazine pesticides in drinking water are established in accordance with hygienic standards. Discussion. The procedure allows separate determination of triazine pesticides when they are co-located in concentrations at and below the corresponding MPC values in drinking and bottled water. The method allows reliably determining the target compounds without the use of hard-to-reach deuterated reference materials. To improve the reliability of the method, as an internal standard it is recommended to use one of the compounds studied, which is not a widely used pesticide, for example, propazine, with mandatory control of the initial matrix for its content. Conclusion. A highly sensitive method for the separate determination of a group of triazine pesticides (simazine, atrazine, propazine, prometrin, metribuzin, metamitron) was developed with their joint presence in drinking water with sensitivity at or below the corresponding hygienic standards.

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