热分离进样-低热容气相色谱-质谱法测定空气中苯系物

Determination of benzene series in air by low heat capacity gas chromatography-mass spectrometry with thermal separation injection

建立了一种热分离进样-低热容气相色谱-质谱法测定空气中苯系物的方法。使用微吸附采样器,安装膜厚为20μm的PLOT-Q捕集短柱采集气体样品,采样流量为100 mL/min,在热分离进样杆中完成目标化合物的脱附后进入DB-5 LTM色谱柱进行分离,使用气相色谱-质谱法定性、定量分析。结果表明,7种苯系物的质量在34.8~1419 ng范围内与各自的色谱峰面积线性关系良好,相关系数均大于0.992,以200 mL采样体积计算,空气中检出限为0.006~0.012 mg/m^(3)。方法的相对标准偏差为2.4%~8.7%(n=6),平均回收率为89%~103%。该方法无需样品前处理,重复性好,检出限满足相关环境质量和排放标准要求,适合空气中苯系物的快速测定。

A method for the determination of benzene series(BTEX)in air by gas chromatography-mass spectrometry(GC-MS)with thermal separation injector was established.A PLOT-Q short column with a membrane thickness of 20μm was used to collect the samples with a micro adsorption sampler.The target compounds were desorbed in the thermal separation injection rod and separated in a DB-5 LTM chromatographic column.The quantitative analysis was performed by gas chromatography-mass spectrometry.The results showed that the peak area of seven benzenes had good linear relationship with their chromatographic peak area in the range of 34.8-1419 ng,the correlation coefficients were more than 0.992,and the detection limits were in the range of 0.006-0.012 mg/m^(3)with the sampling volume was 200 mL.The relative standard deviations were 2.4%-8.7%(n=6),and the recovery rates ranged from 89%-103%.The method has no sample pretreatment,good repeatability and low detection limit.It is suitable for rapid determination of BTEX in air.