预浓缩/柱箱制冷GCMS/FID法测定大气中117种挥发性有机物

建立了罐采样、吸附剂辅助电子制冷预浓缩-柱箱制冷GCMS/FID同时测定大气中117种挥发性有机物(VOCs)的方法。样品经填充吸附剂的电子制冷预浓缩系统除水、除CO₂、浓缩和热脱附后,采用柱箱制冷及GCMS/FID的多维切割单元,将5种C₂-C₃组分切到二维色谱柱进行分离并进入FID检测,甲醛及其他111种VOCs组分留在一维色谱柱进行分离并进入MS检测,甲醛采用SIM模式检测,其余化合物采用Scan模式检测。FID采用外标法定量,MS采用内标法定量。考查了预浓缩系统条件、多维切割条件、质谱条件、气相条件等参数对测试结果的影响,对比了常温柱箱法和柱箱制冷法的效果,并评估了在此优化条件下的方法性能。117种VOCs在0.5—20 nmol·mol^-1(甲醛2.5—100 nmol·mol^-1)范围内线性关系良好,相关系数(R)在0.9924—0.9999,方法检出限为0.071—0.718μg·m^-3,定量限为0.284—2.872μg·m^-3。

Determination of 117 volatile organic compounds in atmosphere by preconcentration/column refrigeration GCMS/FID

A method for the determination of 117 volatile organic compounds(VOCs)in atmosphere by flask sampling,adsorbent-assisted electronic refrigeration preconcentration-CRG oven cooling GCMS/FID was established.After removal of water and CO₂,concentrating and thermal desorption in the electronic refrigeration preconcentration system equipped with adsorbents,five C₂-C₃ components were cut and introduce into the second chromatographic column by the CRG oven cooling and multidimensional cutting unit of GCMS/FID,and then detected by FID.Formaldehyde and other 111 VOC components were separated by the first chromatographic column and detected by MS,formaldehyde was detected by SIM mode,and other compounds were detected by Scan mode.Components in FID are quantified by external standard calibration curve,while cpmponents in Mare quantified by internal standard calibration curve.The condition parameters of pre-concentration system,multi-dimensional cutting,mass spectrometry,and gas chromatography on the test results were investigated.The effect of CRG oven cooling were investigated and evaluated.The good linearity of 117 VOCs are found in the range of 0.5—20 nmol·mol^-1(formaldehyde 2.5—100 nmol·mol^-1),and the correlation coefficient(R)is 0.9924—0.9999.the detection limit of the method were obtained as 0.071—0.718μg·m^-3,and the quantitative limit was 0.284—2.872μg·m^-3.