Determination of 28 Volatile Organic Compoundsin Soil by Gas Chromatography-Mass Spectrometry with Sampling by Purging and Trapping

Methanol was used as extraction agent, a method for the determination of 28 volatile organic compounds (VOCs) in soil by gas chromatography-mass spectrometry with sampling by purging and trapping was proposed. 5.0 g of soil sample was added into 10 mL of methanol. After shaking and settling, 250 μL of extracting solution and a certain amount of the mixed internal standard solution were added into the purging bottle, and made its volume up to 10 mL with water. It was shown that the linear ranges of 28 VOCs standard curves were 1-100 μg·L^-1, with detection limits in the range of 7.4-15.2 μg·kg^-1. Recovery test was made on blank sample by standard addition method, giving results in the range of 79.8%-108%, and RSDs (n=6) of the determined values were in the range of 1.9%-12%. This method was applied to analysis of 2 actual soil samples, with the determined values of chloroform of 22.6 mg·kg^-1 and 24.0 mg·kg^-1, and the other 27 VOCs were not detected.