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    苏玛罐采样-冷阱预浓缩-气相色谱-质谱法测定工业企业附近无组织废气中30种消耗臭氧层物质的含量

    Determination of 30 Ozone-Depleting Substances in Fugitive Gas near Industrial Plants by Gas Chromatography-Mass Spectrometry with Summa Canister Sampling and Cold Trap Preconcentration

    • 摘要: 于当天9,15,20时在工业企业上、下风向4个采样点以流量100 mL·min−1采集无组织废气1 h。所得气体经三级冷阱预浓缩后进入气相色谱-质谱仪,其中的消耗臭氧层物质(ODS)在J&W GASPRO色谱柱上以程序升温条件分离,电子轰击离子源电离,选择离子监测模式检测,二氧化碳匹配的外标法定量。结果表明:30种ODS的摩尔分数在40~800 pmol·mol−1内和峰面积呈线性关系,检出限为1.0~8.0 pmol·mol−1;按照标准加入法进行回收试验,回收率为81.8%~114%,测定值的相对标准偏差(n=6)为0.50%~14%。方法用于工业企业附近无组织废气样品的分析,在上风向采样点的样品中未检出ODS,下风向采样点的样品中均检出了26种ODS,检出量为2.8~518 000 pmol·mol−1,且ODS总量随着采样时间的推移逐渐升高,最高值均出现在20时。

       

      Abstract: Fugitive gas samples were collected for 1 h at flow rate of 100 mL·min−1 from 4 sampling sites located upwind and downwind of an industrial plant on the same day at 09:00, 15:00, and 20:00. The collected gas was introduced into a gas chromatography-mass spectrometer after three-stage cold trap preconcentration. The ozone-depleting substances (ODS) in the samples were separated on the J&W GASPRO column using a temperature-programmed condition, ionized by electron impact ion source, detected in selected ion monitoring mode, and quantified using the external standard method matched for carbon dioxide. It was shown that linear relationships between values of the mass concentrations and peak areas of the 30 ODS were kept in the range of 40–800 pmol·mol1, with detection limits in the range of 1.0–8.0 pmol·mol1. Test for recovery was performed by the standard addition method, giving recoveries in the range of 81.8%–114%, with RSDs (n=6) of the determined values in the range of 0.50%–14%. The proposed method was applied to the analysis of fugitive gas samples near industrial plants. No ODS were detected in samples from the upwind sampling site, while 26 ODS were detected in samples from downwind sampling sites, with detection amounts ranging from 2.8 pmol·mol1 to 518 000 pmol·mol1. Furthermore, the total ODS content increased gradually over the sampling time, with the highest values consistently observed at 20:00.

       

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