METHOD FOR DETERMINING THE MASS CONCENTRATIONS OF ORGANOCHLORINE COMPOUNDS IN CHEMICAL REAGENTS USED IN THE PROCESS OF EXTRACTION, PREPARATION AND TRANSPORTATION OF OIL Russian patent published in 2023 - IPC G01N30/00 G01N33/22 G01N33/26 

FIELD: analytical chemistry.

SUBSTANCE: method for determining the mass concentrations of organochlorine compounds in chemical reagents used in the process of production, preparation and transportation of oil involves sample preparation of the test sample of the chemical reagent by introducing a solvent, extracting chlorine-containing compounds from the extraction mixture, followed by separation of the extraction mixture into non-polar and polar phases. The extract of the non-polar phase is sampled, filtered to obtain the analysed sample, and the content of organochlorine compounds is determined by gas chromatography-mass spectrometry. Sampling is carried out for sample preparation of chemical reagents on a water basis, on a hydrocarbon basis, in the form of a suspension and in a solid state of aggregation. If the chemical reagent is a water-based composition, then a 2-fold extraction of chlorine-containing compounds contained in the reagent is first performed using isooctane as a non-polar solvent in a 1:1 volume ratio. If the chemical reagent is in a solid state of aggregation, then it is preliminarily dissolved in distilled water, followed by 2-fold extraction of the aqueous solution with isooctane in a 1:1 volume ratio. After the introduction of extractants, each extraction is carried out for 2-3 minutes, after settling the mixture for 10 minutes, the lower layer is drained, and the upper isooctane extracts are combined, filtered through a “red ribbon” paper filter, and the analysed sample is obtained. For suspension chemical reagents, a 2-fold sequential extraction of chlorine-containing compounds contained in the reagent is preliminarily performed with a polar solvent, which is distilled water in a volume ratio of 1: 1 for 2-3 minutes, after settling for 10 minutes, the second aqueous extract is combined with the first one, followed by 2-fold extraction with isooctane for 2-3 minutes, after settling the extraction mixture for 10 minutes, the lower layer is drained, both upper isooctane extracts are combined, filtered through a “red ribbon” paper filter, and the analysed sample is obtained. If the chemical reagent is a hydrocarbon-based formulation, then the test sample is obtained by dissolving the reagent in isooctane in a 1:1 volume ratio. To determine the mass concentrations of organochlorine compounds in the analysed samples of chemical reagents, the chromato-mass spectrometer is preliminarily calibrated using calibration solutions of organochlorine compounds in isooctane. A calibration graph is built for each organochlorine compound, reflecting the dependence of the peak area on the concentration of the introduced substance. Then organochlorine compounds are identified by the retention time of the corresponding individual organochlorine compounds and the obtained spectra are compared with the library ones. The completeness of extraction is determined by the degree of extraction of organochlorine compounds of at least 85% for water-based reagents and in the solid state of aggregation and at least 75% for suspension chemical reagents. To do this, a known amount of individual organochlorine compounds is dosed into reagents, the subsequent extraction of organochlorine compounds is performed according to the sequence described above, the obtained samples are analysed by gas chromatography-mass spectrometry, and the concentration of individual organochlorine compounds is determined by the absolute calibration method. The results are compared with the amount entered. For hydrocarbon-based chemicals, on-line control of the results of measurements of the mass concentration of organochlorine compounds is carried out using the additive method. A solution of target at least five organochlorine compounds in isooctane with a known concentration of components is used as an additive. Two working samples of the chemical reagent are taken and an additive is made to one of them so that the content of organochlorine compounds increases by 50-100% as compared to the initial one, the samples are analysed under repeatability conditions.

EFFECT: ensuring high accuracy and reliability in determining the concentrations of organochlorine compounds in chemical reagents presented in various physical forms, which was facilitated by the sample preparation of the test sample of the chemical reagent to obtain the analysed sample, accurate and reliable determination of the source of commercial oil pollution in the form of organochlorine compounds and organically combined chlorine.

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