超高效液相色谱串联质谱法测定成都市某饮用水厂中的亚硝胺类消毒副产物

Determination of Nitrosamines Disinfection By-products in Drinking Water Treatment Plant in Chengdu City by Ultra-high Performance Liquid Chromatography Tandem Mass Spectrometry

自来水中亚硝胺类消毒副产物与常见的卤代消毒副产物比较,存在更高的毒性和致癌风险,近年来引起更多重视。拟在现有相关研究基础上优化自来水中亚硝胺类消毒副产物的超高效液相色谱串联质谱(UPLC-MS/MS)的检测方法,并对成都市某次氯酸钠消毒工艺的自来水厂中饮用水处理工艺过程中的亚硝胺浓度进行调查。选用活性炭固相萃取柱对水样中ng/L级别的亚硝胺类副产物进行富集净化,色谱柱采用ACQUITYPremierHSST3柱(1.8μm,2.1 mm×50 mm),乙腈和10 mmol/L乙酸铵/乙酸缓冲溶液(pH=4.1)作为流动相进行梯度洗脱,电喷雾离子源正离子模式,采集时选择多反应监测模式,以二甲基亚硝胺-d_(6)为回收率指示物,亚硝基二丙胺d_(14)为定量内标,建立UPLC-MS/MS同时检测自来水中主要的9种亚硝胺类消毒副产物的分析方法。针对9种亚硝胺的方法检出限为1.04~2.19 ng/L,回收率74.71%~91.58%,标准曲线(省略样品前处理步骤)的线性范围为5~200μg/L,线性相关系数r>0.99。二甲基亚硝胺的检出限低于《生活饮用水卫生标准》(GB 5749-2022)中规定的限值。前处理方法操作简单,能同时测定9种亚硝胺类消毒副产物。2022年4月对成都市某自来水厂进行实际调查,9种亚硝胺类消毒副产物均未检出,说明水源水中氨氮浓度较低的情况下,次氯酸钠消毒工艺对亚硝胺的形成影响不明显。

Compared with common halogenated disinfection byproducts,N-nitrosamines in drinking water have higher tox-icity and carcinogenic risk,which has attracted more attention in recent years.The detection method of nitrosamines dis-infection by-products in waterworks was optimized by ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS),and the method was applied to a drinking water plant in Chengdu under a sodium hypochlorite disin-fection process.Active carbon column was used for solid-phase extraction at trace level(ng/L)in water samples.AC-QUITY Premier HSS T3 column was used for separation,acetonitrile-10 mmol/L ammonium acetate and acetic acid buff-er solution(pH=4.1)as mobile phase for gradient elution.An analytical method for simultaneous detection of 9 nitros-amines disinfection by-products in drinking water by UPLC-MS/MS was established,using NDMA-d_(6) as recovery indica-tor and NDPA-d_(14) as internal quantitative standard by ESI+multiple reaction detection modes.The method detection limits of this analytical method for the nine nitrosamines range from 1.04-2.19 ng/L.The recoveries were 74.71%-91.58%.The liner range(without sample pretreatment)was 5-200μg/L,with r>0.99.The detection limit of dimeth-ylnitrosamine is lower than that speified in the Standards for Drinking Water Quality(GB 5749-2022).The sample pretreatment method is simple.This method can determine 9 nitrosamines disinfection byproducts simultaneously.In April 2022,an investigation of a drinking water plant in Chengdu was carried out.It was found that none of the 9 main nitrosa-mines were detected.The effect of sodium hypochlorite disinfection process on the formation of nitrosamine was not obvi-ous when concentrations of ammonia nitrogen were relatively low.