METHOD FOR VAPOUR-PHASE DETERMINATION OF WEIGHT CONCENTRATION OF CARBON TETRACHLORIDE, METHYLENE CHLORIDE, CHLOROFORM, 1,2-DICHLOROETHANE, 1,1,2-TRICHLOROETHANE IN BOTTOM DEPOSITS BY GAS CHROMATOGRAPHY

摘要

FIELD: chemistry.;SUBSTANCE: invention relates to analytical chemistry and can be used for determination of VOC (volatile organochlorine compounds): carbon tetrachloride, methylene chloride, chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane in bottom sediments. Method of determining content of VOC in bottom deposits using analysis of equilibrium vapour involves determining VOC on a capillary chromatographic column in flow of carrier gas, which is a nitrogen, formation and detection of investigated ions formed in flame using a flame ionisation detector. Method includes preparing a basic solution with concentration of VOC of 8 mg/cm³, with good storage for 2 months at temperature of -2 °C to -10 °C, preparing an intermediate solution with VOC concentration of 10 mg/dm³ and diluting basic solution with purified water. Method then includes preparing calibration solutions for a range of concentrations of VOC of 0.05-2.5 mg/dm³ by diluting with purified water said intermediate solution, and calibrating chromatograph. Further, a calibration curve is plotted by adding a previously extracted vapour phase of calibration solutions. After thermostating analysed sample, collecting vapour phase and using a vapour-phase syringe feeding into evaporator chromatograph, obtained data are processed using computer program GCsolution, which is equipped with chromatographic complex SHIMADZU GC-2010, and qualitative identification and quantitative readings of device. Content of each component C_i, mg/kg of dry substance is calculated mathematically.;EFFECT: high consistency and accuracy of analysis, achieving acceptable results repeatability (convergence) of parallel samples and easier analysis in environmental monitoring conditions.;1 cl, 6 tbl, 2 dwg