Determination of Petroleum Hydrocarbons (C₁₀-C₄₀) in Soil of Chemical Industrial Park by Gas Chromatography with Accelerated Solvent Extraction

After processing the sample according to the standard, about 10 g of the sample was taken, and 8 g of the burned diatomaceous earth was added. The mixture was mixed evenly, and accelerated solvent extraction was performed with acetone-n-hexane mixed solution at a volume ratio of 1∶1. The extract was concentrated to about 1 mL and purified according to HJ 1021—2019. The purified liquid was introduced into the gas chromatograph, and the petroleum hydrocarbons (C₁₀-C₄₀) were separated by the heating program on HP-5 chromatographic column, and quantified by the external standard method. It was shown that linear relationship between values of the mass concentration of petroleum hydrocarbons (C₁₀-C₄₀) and total peak area within the retention time window of 5.09-32.78 min was kept in the range of 31-6 200 mg·L⁻¹, with detection limit (3.143s) of 3.93 mg·kg⁻¹. Test for recovery was made according to the standard addition method, giving recoveries in the range of 96.8%-102%, and RSDs (n=6) of the determined values in the range of 8.2%-9.0%. The relative error of the determined value of certified reference material was −9.7%. The proposed method was used for the analysis of 50 soil samples from 15 sampling points in the chemical industrial park. Petroleum hydrocarbons (C₁₀-C₄₀) were detected in 46 samples, with the highest detection amount of 540 mg·kg⁻¹.