Determination of 8 Malodorous Substances Containing Sulfur in Air of Closed Environment by Gas Chromatography-Mass Spectrometry with Summa Canister Sampling

A method for determination of the 8 malodorous substances containing sulfur in air of closed environment by gas chromatography-mass spectrometry with Summa canister sampling was established. After Summa canister sampling and pre-concentration injection with injection volume of 800 mL, the sample was separated on a DB-VRX quartz capillary column as stationary phase by column heating program, to obtain the 8 malodorous substances containing sulfur, including methyl mercaptan, ethyl mercaptan, methyl sulfide, methyl ether sulfide, carbon disulfide, diethyl sulfide, dimethyl disulfide and thiophene. In mass spectrometry, the residence time was 200 ms; diethyl sulfide was interfered with 1,2-dichloropropane, and dimethyl disulfide was interfered with ethyl isobutyrate in the full scan (SCAN) mode for qualitative analysis, while the interfering components had no response in the selective ion monitoring (SIM) mode for quantitative analysis, and the selected quantitative ion for ether was m/z 90 and the quantitative ions for dimethyl disulfide were m/z 94,79. As shown by the results, the linear ranges of the standard curves for the 8 malodorous substances containing sulfur were in the same range of 0.75-6.0 nmol·mol^-1, with detection limits (3.14s) in the range of 0.14-0.32 nmol·mol^-1. The mixed standard gas was determined 7 times continuously, with RSDs (n=7) of determined values in the range of 3.2%-7.8%. Test for recovery was made by standard addition method, giving values of recovery in the range of 96.0%-118%. This method was applied for determination of the actual sample, and only carbon disulfide, methyl ethyl sulfide and dimethyl disulfide were detected among the 8 malodorous substances containing sulfur, with the detected amounts ranged from 0.23 nmol·mol^-1 to 2.50 nmol·mol^-1.