吹扫捕集/气相色谱-质谱法同时测定环境水样中5种三卤甲烷

Simultaneous Determination of Five Trihalomethanes in Water by Gas Chromatography-Mass Spectrometry Coupling with Purge and Trap Pretreatment

通过优化吹扫捕集前处理条件,建立了水中5种三卤甲烷(一溴二氯甲烷、一氯二溴甲烷、二氯碘甲烷、溴氯碘甲烷和碘仿)同时测定的吹扫捕集/气相色谱-质谱方法。将采集的水样过滤后,移于顶空瓶中,通过吹扫捕集前处理将待测物从水中吹脱,再用捕集器吸附待测物,随后经热解吸进入气相色谱柱分离,质谱检测器测定,外标法定量。在优化的测定条件下,5种三卤甲烷在0.50~50.0μg/L质量浓度范围内,线性良好,相关系数(r)≥0.9991,检出限为0.001~0.02μg/L,定量限为0.0030~0.060μg/L,回收率为96.4%~103.4%,相对标准偏差(RSD)为0.96%~5.8%。建立的方法简便快捷,具有高特异性和高灵敏度,适用于水中5种三卤甲烷的同时测定,可为环境水中三卤甲烷的日常监测提供技术支持。

Trihalomethanes(THMs),a class of chlorinated disinfection by-products(DBPs),were generated from chlorine dioxide,chloramine,chlorine,and other chlorinated disinfectant used in water treatment.They have been strictly regulated in drinking water because they are cytotoxic,genotoxic and carcinogenic.Thus,it is significant to develop a sensitive and accurate method for the determination of THMs in water.Herein,a convenient and sensitive method for the simultaneous determination of five THMs including bromodichloromethane,chlorodibromothane,dichloroiodomethane,bromochloroiodomethane,and iodoform in water was developed by gas chromatography mass spectrometry(GC-MS)coupling with purge and trap pretreatment.The water sample was filtered through 0.45μm nitrocellulose syringe filter,then 40 mL of water was placed in a headspace bottle and concentrated using purge and trap technique.The analytes were separated by a gas chromatographic column,and detected using mass spectrometry,the quantitative method used was an external standard method.Under the optimized conditions,a good linearity was achieved for the 5 THMs as the mass concentration ranging from 0.50 to 50μg/L,the linear correlation coefficients(r)were higher than 0.9991.The method detection limit(LOD)was 0.001-0.02μg/L,and the limit of quantitation(LOQ)was 0.0030-0.060μg/L.Good recoveries were obtained ranging 96.4%-103.4%with relative standard deviations(RSDs)of 0.96%-5.8%.The proposed method was sensitive,accurate,and convenient,which can be applied for the simultaneous determination of 5 THMs in water and provide a beneficial reference for the bulk water quality monitoring.