Herbicides from the group of nitrodiphenyl ethers: applications in Ukraine, control methods, methods for determination of oxifluorphene residues in soybean grain and oil

A review of analytical methods for the determination of herbicide residues from the group of nitrodiphenyl ethers in the environment and agricultural products, developed and validated a method for oxyfluorfen determination in soybean grain and oil method GC/ECD, which meets regulatory requirements and solves the problem of toxicant control in the above matrices. The developed method uses modern methods of sample preparation, identification and quantification of oxyfluorfen (selective extraction, capillary gas-liquid chromatography (GC/ECD GC/MS). The method is validated according to EU requirements) (SANTE/12682/2019 quality control and analytical validation procedures for pesticide residues analysis in food and feed). Key words: gas-liquid chromatography, mass spectrometry, herbicides, nitrodiphenyl ethers, control, residual amounts.

Determination of curcumin in bouillon cubes by high-performance thin-layer chromatography

Currently, high-performance thin-layer chromatography (HPTLC) is widely used to control product quality in the pharmaceutical and food industries. In the manufacture of food products, the most important requirement is the control of the content of various additives (preservatives, dyes, antioxidants). For the first time, a method for determining curcumin by high-performance thin-layer chromatography in bouillon cubes "Gallina Blanca" was proposed. Detection was carried out by densitometric scanning using CAMAG equipment when measuring absorbance at a wavelength 265 nm. The method is based on determining the peak area of curcumin in the chromatogram depending on its concentration. Curcumin content is determined by the calibration curve. The developed method was validated by the following tests: specificity, linearity, accuracy and detection limit. The calibration curve is linear in the range of curcumin concentrations from 120 to 520 ng/spot, the detection limit is 65 ng/spot. The specificity of the method is based on the ability to unambiguously evaluate the analyte in the presence of other components and is confirmed by using an external standard. The spots on the chromatograms of the test solution and the reference solution coincide in the value of Rf, which confirms the specificity of the method. Accuracy was evaluated according to the results of the analysis of various samples. The requirement for statistical insignificance of systematic error is fulfilled. The proposed method is express, characterized by satisfactory metrological characteristics, ease of implementation. Key words: high-performance thin-layer chromatography, curcumin, validation.

Improvement of analytical determination of residual quantities of active substances of the triasole class in juices

Today, the most common among fungicides approved for use in Ukraine, as well as in other countries, are compounds of the triazole class. Juices, as a product of processing agricultural raw materials, can be consumed by a wide range of the population. The purpose of work was to develop analytical methods for compound of triazole (difenoconazole and propiconazole) in juices to ensure quality control of agricultural products grown with the use of these fungicides. Conditions for chromatography of difenoconazole and propiconazole using gas-liquid chromatography with capillary column SH-Rxi-5ms (30 m 0,25 mm) and electron capture detector were determined. Optimal conditions of difenoconazole chromatography were established: thermostat column temperature - 280 C, evaporator temperature - 290 C, detector thermostat temperature - 300 C. Retention time: isomer 1 - (6,91 +- 0,1) minutes, isomer 2 - (7,04 +- 0,1) minutes. The linear range of detection is 0,01-0,04 ug/cm3. The optimal conditions for chromatography of propiconazole were also established: the temperature of the column thermostat in the programming mode: initial T - 100 C with an exposure of 1 minute; from 90 C to 260 C - rate of temperature rise 40 C/min; exposure - 7,45 minutes; evaporator temperature - 270 C, detector temperature - 280 C. The retention time under these conditions was 3,49 +- 0,1 minutes for isomer 1 and 3,57 +- 0,1 minutes for isomer 2. The linear range of detection is 0,01-0,05 ug/cm3. The calibration dependence of the area of peaks of the investigated substances on their concentration was established and described by the linear regression equation.

Methodological aspects of assessment of the state of chemical pollution and water quality of surface waters in Ukraine

The main sources of chemical pollution of surface water bodies of Ukraine are shown and it is noted that the ecosystem of the environment and water resources, being under constant man-caused load, tend to steadily deteriorate the ecological condition. Methods for assessing the quality of surface waters using the maximum allowable concentrations of harmful substances in water and a comprehensive assessment of the ecological status of surface water by integrated hydrochemical parameters are described. International approaches to the assessment of the state of surface water bodies are considered. It is noted that the most complete information on the state of the aquatic ecosystem can be obtained using a set of physicochemical and biological parameters. There are shortcomings in the monitoring of organic micro-pollutants in surface waters. The analysis of the international experience of determination of water quality and parameters of toxicological action of organic micro-pollutants with application of chemo-informative methods for modeling of an ecological condition of water systems is carried out.