苏玛罐采样-预浓缩-气相色谱-质谱法测定环境空气中34种消耗臭氧层物质的含量

Determination of 34 Ozone Depleting Substances in Ambient Air by Gas Chromatography-Mass Spectrometry with Summa Canister Sampling and Pre-Concentration

提出了苏玛罐采样-预浓缩-气相色谱-质谱法同时测定空气中34种消耗臭氧层物质(ODS)的分析方法。采用硅烷化的苏玛罐采集环境空气,用三级冷阱预浓缩、富集、热解吸,将解吸后的样品在Gas-Pro毛细管色谱柱(60 m×0.32 mm)上进行程序升温气相色谱分离,质谱分析采用全扫描(SCAN)模式和选择离子监测(SIM)模式,外标法定量。结果表明:34种ODS的物质的量分数在一定范围内与对应的响应强度呈线性关系,检出限(3.14s)为4.17~11.4 pmol·mol^(-1)。按照标准加入法进行回收试验,回收率为81.4%~95.8%,测定值的相对标准偏差(n=6)小于10%。将上述方法分析来自天津市某采样点的环境空气样品,13种ODS被检出,检出量为16.4~456 pmol·mol^(-1)。

A method was proposed for determination of 34 ozone depleting substances(ODS) in ambient air by gas chromatography-mass spectrometry(GC-MS) with summa canister sampling and pre-concentration. The ambient air was collected by summa canister alkylated, with pre-concentration, enrichment, and thermal desorption by three-stage cold trap. The desorbed sample was separated on Gas-Pro capillary column(60 m×0.32 mm) under programmed temperature by GC. Full scan(SCAN) mode and selected ion monitoring(SIM) mode were adopted in MS analysis, and external standard method was used for quantification. As shown by the results, linear relationships between values of response and mole fraction of 34 ODS were found in definite ranges, with detection limits(3.14s) in the range of 4.17-11.4 pmol·mol^(-1). Test for recovery was made by standard addition method, giving results in the range of 81.4%-95.8%, with RSDs(n=6) of determined values less than 10%. The ambient air samples from a sampling point in Tianjin were analyzed by the above method, and 13 ODS were detected, with the detection amounts of 16.4-456 pmol·mol^(-1).