非抑制型离子色谱串联质谱法同时测定饮用水中卤乙酸和卤氧化物

Simultaneous determination of haloacetic acids and oxyhalides in drinking water by non-suppressed ion chromatography-tandem mass spectrometry

本文建立了一种基于非离子抑制型离子色谱-电喷雾离子化-串联质谱(IC-ESI-MS/MS)的卤乙酸和卤氧化物分析方法,解决了当前卤乙酸检测预处理过程复杂和卤氧化物检测灵敏度低的问题,本方法中仅需的样品前处理为0.45μm滤膜过滤.样品采用Dionex IonPac AS16色谱柱进行分离,使用甲胺水溶液和乙腈作为混合流动相.采用电喷雾负离子(ESI-)模式,多反应监测模式(MRM)进行质谱分析.本文系统研究了甲胺水溶液的浓度及比例对分析物保留时间和响应值的影响,确定最优流动相条件为0.7 mol·L-1甲胺水溶液/乙腈,体积比30/70,等度洗脱.在此条件下,9种卤乙酸和3种卤氧化物在0.5—100μg·L-1范围内均具有很好的线性关系(r>0.995),检出限为0.052—0.270μg·L-1,检测下限为0.208—1.080μg·L-1;在自来水中加标回收率为74.9%—114.9%,相对标准偏差为1.2%—8.7%.运用本方法对模拟加氯消毒水样及无锡市的自来水进行检测,两次测量结果偏差小,二氯乙酸和三氯乙酸检出浓度最高.本方法灵敏快速、操作简便,为国家标准《生活饮用水标准检验方法》(GB/T5750)中二氯乙酸、三氯乙酸、氯酸盐和溴酸盐等指标的检测方法修订提供了技术支撑.

An determination method of haloacetic acids(HAAs)and oxyhalides using non-suppressed ion chromatography electrospray ionization tandem mass spectrometry(IC-ESI-MS/MS)was established to solve the problems of complex pretreatment for HAAs detection and the low sensitivity for oxyhalides detection.In this method,the only pretreatment was the process of 0.45μm membrane filtration.The samples were separated by Dionex IonPac AS16 column,and aqueous methylamine solution and acetonitrile were used as the mixed mobile phases.Negative electrospray ionization(ESI-)mode and multiple reaction monitoring mode(MRM)were used for mass spectrometry analysis.The effects of concentration and proportion of aqueous methylamine solution on retention time and response value of the analytes were studied,and the optimal mobile phase condition was determined to be 0.7 mol·L-1 aqueous methylamine solution/acetonitrile,with a volume ratio of 30/70 and elution in equal degree.Under the optimal condition,all of the 12 analytes had good linear relationships(r>0.995)in the range of 0.5—100μg·L-1,with the detection limits of 0.052—0.270μg·L-1,the minimum quantitative detection limits of 0.208—1.080μg·L-1.The recoveries of the spiked 12 analytes in tap water were 74.9%—114.9%with relative standard deviations ranging from 1.2%to 9.0%.This method was applied to analyze the simulated chlorinated water and tap water from Wuxi.The deviation of the duplicate analyses was small,and the concentrations of dichloroacetic acid and trichloroacetic acid were the highest.This method is sensitive,rapid and easy to operate,which provides technical support for the revision of the detection methods of dichloroacetic acid,trichloroacetic acid,chlorate and bromate in the"Standard Examination Method for Drinking Water"(GB/T5750).