Introduction. From the evaluation of the positions of residual quantities of pesticides, the hygienic safety assessment of imported food products is most relevant under the current agreement on a free trade zone between the EAEU and the Socialist Republic of Vietnam, as well as in connection with a large list of chemical plant protection products used during the vegetation of crops. The purpose of the study. Rating the level of residual quantities of pesticides in samples of selected food products produced in Vietnam is the purpose of the study. Research objectives. To quantify 42 active ingredients of pesticides (and their metabolites) in samples of rice grain, dragon fruit (pitahaya), avocado, mango and banana (fresh and dried) are the research objectives. Material and methods. Multicomponent and individual methods based on LC and GC with MS-detection and FLD were used to identify active ingredients of pesticides. The sample preparation procedure with QuEChERS technology was used for the multi residues determination of the 40 compounds. The determination of avermectins (abamectin and emamectin benzoate) was carried out after the conversion of substances into fluorogenic derivatives. Results. Residual amounts of tebuconazole (rice - 0.53 ppm, mangoes - 0.26 ppm, avocado - 0.15 ppm), fludioxonil (rice - 0.017 ppm), imidacloprid (dried mangoes - 0.01 ppm), carbendazim (dried mangoes - 0.011 ppm) were identified in single samples No residual avermectins have been identified. The content of substances in the analyzed samples of dragon fruit (pitahaya) did not exceed 0.01 ppm. Discussion. The results obtained in the work are compared with the data of the annual pan-European and national monitoring, information on which is publicly available (2017), including imported goods, according to which rice and dragon fruits as objects of monitoring are given increased attention. Conclusions. The safety of certain types of food products imported from Vietnam is shown by the content of residual quantities of pesticides.
In the work there are presented results of studies on the validation of the gas chromatographic (GC) methodfor the determination of chlorothalonil residue amounts in peaches with the use of electron capture detector (ECD). For the analytical control there was selected such stone fruit crop as the peach, referring to the crops, the most contaminated with residue amounts ofpesticides. There was justified the necessity of the inclusion in the procedure of the detection of the method of confirmation, based on mass spectrometry detection (MSD) (the type of ionization - electron impact). The significant source of the obtaining of incorrect data in the identification with the use of ECD of ions are shown to be phthalates, visualized in the chromatogram as intense and/or broad peaks. Mass spectra of compounds of the class ofphthalates are characterized by the dominant peak of the ion with the value of (mass/ charge) 149, just on this peak the detection of low molecular weight phthalates occurs in various matrices, on the spectrum there are also recorded typical ions corresponding to fragments of radical residues. The combination of the use of various types of the detection allows to prove that the revealed response (detector signal) is caused just by the analyte, but not the impurities, and optionally to optimize chromatographic conditions towards to the obtaining reliable results. The lower limit of the quantitation of chlorothalonil in peach fruits accounts for 0.01 mg/kg, determined with a signal/noise ratio of 10. The range of measured concentrations is volatile between 0.01-0.1 mg/kg, recovery rate of chlorothalonil from samples of peaches, established according to results of the analysis of model samples with the introduction of the substance in four points along the detection range, was 84-102%, the SD value of the repeatability varies in the range of 2.0-5.8%.
Introduction. The implementation of new pesticides into agricultural practice is possible only after their comprehensive toxicological and hygienic study and hygienic regulation, which is the basis for the preventing their adverse effects on the health of workers and the population, as well as on the environment. The rationale for the maximum allowable concentration of the pesticide’s active substance in the soil is based on the study of the main hazard indices established experimentally. The translocation hazard index in the soil-plant system, along with other indices of hazard (migrational-water, migrational-air and general-sanitary) in soil-water, soil-air and soil-microbiocenosis systems, reflects one of the indirect effects of xenobiotics on the contacting medium, by which the limiting index of the maximum allowable concentration of the pesticide’s controlled active ingredient is established. Material and methods. At this stage, studies have been carried out to investigate the translocation hazard index characterizing migration processes of the pesticide based on the active substance 2-methyl-4-chlorophenoxyacetic acid (phenoxyacetic acid class) from the soil to plants. The studies were performed with taking into account the observance of the requirements for carrying out experimental studies in standard, comparable soil and microclimatic conditions, and also in accordance with the principle of the extremality, which contributes the maximum migration of the studied chemical to the media (water, air, plant) in contact with the soil. To obtain a scientifically grounded threshold concentration of the substance of this hazard index, the study was carried out using a special sealed climatic chamber with controlled conditions of the ranges of illumination, temperature, and humidity of the air. Results. Based on the obtained experimental data, the threshold concentration of the controlled active substance was determined according to the translocation hazard index, in which the accumulation of the substance by plant phytomass at the time of harvest does not exceed the maximum permissible level (MRL) for food products.
Introduction. Cereal grain is an important part of the human daily diet and belongs to a large number of food items produced and consumed throughout the world. Cereals are cultivated using a long list of chemical plant protection products (herbicides, insecticides, fungicides, growth regulators). In this connection, the analysis of pesticide residues, including optimization, development of monitoring methods, and programs, is of particular importance. Purpose of the work. To create a multicomponent method for determining residual amounts of pesticides of various chemical classes and their metabolites in cereals. Material and methods. The identification and quantitative determination of the active substances of pesticides of various classes (neonicotinoids, triazoles, imidazoles, pyrethroids, organophosphorus compounds, strobilurins, etc.) in the joint presence were performed by methods based on the use of liquid and gas-liquid chromatography with mass spectrometric detection. The QuEChERS technology was used as a sample preparation method, based on the extraction of pesticides with an organic solvent from a homogenized grain sample in the presence of salts containing citrate buffer and purification of the extracts from polar compounds by solid-state dispersion extraction. Results. The developed multicomponent method for determining the residual amounts of pesticides of various chemical classes and their metabolites (40 items in total) in cereals was used to control the levels of xenobiotics studied in wheat, barley and corn samples produced in various regions of the Russian Federation (Moscow, Leningrad, Orel, Omsk, Voronezh, Ryazan, Rostov, Volgograd regions, Krasnodar Area), as well as in rice grain (the country of origin is the Socialist Republic of Vietnam) purchased using a consumer buying process. The identified levels of individual active substances were significantly lower than the established values of the maximum allowable level. Conclusion. The developed method is aimed at methodological support of food safety control.
The modern technique for the determination of 2,4-D, that belongs to global environmental pollutants, including the use of the technology of sample preparation - dispersive solid-phase-liquid extraction (QuEChERS), new for products of animal origin, has been developed. The sample preparation procedure includes the steps of: preliminary freezing of the sample to be analyzed, extraction with acetonitrile containing 1% acetic acid in the presence of MgSO4 and NaCl, purification by dispersive solid-phase extraction using a mixture of sorbents based on primarysecondary amine, octadecylsilane and graphitized carbon black, the freeze of the solution - at the last stage. Using the proposed technique allows to isolate the desired component from a matrix with a high content of animal fat into a selected organic solvent with high efficiency, that made it possible to expand significantly the arsenal of analytical equipment used to detect residual amounts of 2,4-D in food products of agricultural production, for example milk, eggs and offal (liver, kidney): tandem liquid mass-spectrometry (HPLC-MS/MS), gas-liquid chromatography with mass-selective and electron-capture detectors (GLC-MSD, GLC-ECD). The lower limit of the quantitative determination is 2,4-D: 0,005 mg/kg for milk and eggs, 0.05 mg/kg for the liver and kidneys. Completeness of extraction is 85-94%, RMS of repeatability is 3,4-11,4%.
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