材料期刊网

采用热脱附(TD)结合气相色谱-三重四极杆串联质谱(GC-MS/MS)建立了环境空气中 23 种挥发性有机物( VOCs)同时检测的分析方法.空气样品通过主动采样的方式富集到装有 Tenax-TA填料的热脱附管中,热解吸后在选择反应监测( SRM)模式下用 GC-MS/MS进行检测,内标法定量.结果表明,23种 VOCs在 0. 01~1 ng 和 1~100 ng低、高两个范围内线性关系良好,相关系数(r2)均大于 0. 99,方法定量限为 0. 000 08~1 μg/m3.加标水平为2、10和50 ng时,23种VOCs的平均回收率为77%~124%.除了最低加标水平的氯苯,相对标准偏差( RSD,n=6)均小于20%.对市内3个采样点的环境空气进行测定,其中苯、甲苯、乙苯、二甲苯、苯乙烯、1,2,4-三甲基苯和六氯丁二烯均有检出.实验证明,该 TD和 GC-MS/MS相结合的检测方法具有准确、可靠、灵敏度高等优点,适用于环境空气中 VOCs的同时测定.

A method was established for the simultaneous determination of 23 volatile organic compounds( VOCs)in ambient air with combination of thermal desorption( TD)and gas chro-matography-triple quadrupole tandem mass spectrometry( GC-MS/MS). The air samples were collected by active sampling method using Tenax-TA sorbent tubes,and desorbed by thermal desorption. The analytes were determined by GC-MS/MS in selected reaction monitoring ( SRM)mode,and internal standard method was applied to quantify the VOCs. The results of all the 23 VOCs showed good linearities in low level(0. 01-1 ng)and high level(1-100 ng) with all the correlation coefficients(r2)more than 0. 99. The method quantification limits were between 0. 000 08-1 μg/m 3 . The method was validated by means of recovery experiments( n=6)at three spiked levels of 2,10 and 50 ng. The recoveries between 77% and 124% were gener-ally obtained. The relative standard deviations( RSDs)in all cases were lower than 20%,except for chlorobenzene at the low spiked level. The developed method was applied to determine VOCs in ambient air collected at three sites in Shanghai. Several compounds,like benzene,tol-uene,ethylbenzene,m-xylenes,p-xylenes,styrene,1,2,4-trimethylbenzene and hexachloro-butadiene were detected and confirmed in all the samples analyzed. The method is highly accu-rate,reliable and sensitive for monitoring the VOCs in ambient air.