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    苏玛罐采样-气相色谱-质谱法测定密闭环境中8种含硫恶臭物质的含量

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

    • 摘要: 建立了苏玛罐采样-气相色谱-质谱法测定密闭环境中8种含硫恶臭物质含量的方法。样品经苏玛罐采样,预浓缩进样,进样量为800 mL,以DB-VRX石英毛细管色谱柱为固定相,采用柱升温程序分离得到甲硫醇、乙硫醇、甲硫醚、甲乙硫醚、二硫化碳、乙硫醚、二甲二硫和噻吩等8种含硫恶臭物质。质谱分析时,驻留时间为200 ms;以全扫描(SCAN)模式定性分析时,1,2-二氯丙烷干扰乙硫醚、异丁酸乙酯干扰二甲二硫的检测,而在选择离子监测(SIM)模式下定量分析时,干扰组分无响应,选择乙硫醚的定量离子为m/z 90,二甲二硫的定量离子为m/z 94,79。结果表明:8种含硫恶臭物质的标准曲线的线性范围为0.75~6.0 nmol·mol-1,检出限(3.14s)为0.14~0.32 nmol·mol-1。连续7次测定混合标准气体,所得测定值的相对标准偏差(RSD,n=7)为3.2%~7.8%。按标准加入法进行回收试验,回收率为96.0%~118%。方法用于实际样品的测定,8种含硫恶臭物质中仅二硫化碳、甲乙硫醚、二甲二硫检出,检出量为0.23~2.50 nmol·mol-1

       

      Abstract: 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.

       

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