PM_(2.5)中Cr(Ⅵ)的采集与分析方法优化研究  

Verification and Optimization of Sampling and Analytical Method to Measure Cr(Ⅵ) in Ambient PM_(2.5)

作　　者：王橹玺 郭敬华[2] 李慧[1] 张文杰[1] 王涵[1] WANG Luxi;GUO Jinghua;LI Hui;ZHANG Wenjie;WANG Han(State Key Laboratory of Environmental Criteria and Risk Assessment,Chinese Research Academy of Environmental Sciences,Beijing 100012,China;Beijing Normal University,Beijing 100875,China)

机构地区：[1]中国环境科学研究院,环境基准与风险评估国家重点实验室,北京100012 [2]北京师范大学,北京100875

出　　处：《环境科学研究》2022年第4期956-963,共8页Research of Environmental Sciences

基　　金：国家重点研发计划项目(No.2019YFC0214200);国家环境保护公益性行业科研专项项目(No.201409022)。

摘　　要：环境空气中的六价铬[Cr(Ⅵ)]对人体健康及生态环境有较大影响,但由于测量大气中Cr(Ⅵ)有诸多困难,目前国内对Cr(Ⅵ)浓度的观测相对较少.为建立可靠、灵敏度高的大气PM_(2.5)中Cr(Ⅵ)的检测方法,构建了基于离子色谱-电感耦合等离子体质谱联用(IC-ICP-MS)分析Cr(Ⅵ)的方法,并对PM_(2.5)中Cr(Ⅵ)的采样与提取方法进行了优化,同时应用该方法在北京市进行了样品采集与分析.结果表明:①样品采集前,为了降低空白滤膜中Cr背景值,滤膜的预处理优化方式为将滤膜浸泡在10%的硝酸溶液中约10 h,超纯水冲洗后在0.12 mol/L碳酸氢钠溶液中浸泡约10 h;在样品提取过程中,将超声温度维持在25℃以下,且保证采样后样品保存时间少于29 d,能有效提高样品回收率.②对IC-ICP-MS测定大气PM_(2.5)中Cr(Ⅵ)的方法进行优化后,其检出限为0.0015 ng/m^(3),加标回收率为92.8%,精确度为7.8%,较离子色谱法检出时间更短、检出限更低,能准确测定环境空气PM_(2.5)中的ρ[Cr(Ⅵ)].③基于采集到的样品分析表明,北京市PM_(2.5)中ρ[Cr(Ⅵ)]平均值为(0.095±0.104)ng/m^(3).研究显示,构建的IC-ICP-MS方法对Cr(Ⅵ)的检出限(0.0015 ng/m^(3))低于GB 3095—2012《环境空气质量标准》中Cr(Ⅵ)的参考限值(0.025 ng/m^(3)),且在环境空气中具有较好的稳定性,满足国内环境空气中Cr(Ⅵ)的测定需求.The hexavalent chromium in ambient air has a great impact on human health and the ecological environment.Due to the challenges in sampling and analysis for the determination of Cr(Ⅵ)in ambient air,there are few observations of hexavalent chromium concentration in China.In order to establish a reliable and high-sensitivity method for the determination of hexavalent chromium in ambient PM_(2.5),Ion Chromatography-Inductively Coupled Plasma Mass Spectrometry(IC-ICP-MS)instrument was used to detect hexavalent chromium,and the sampling and extraction method of Cr(Ⅵ)in PM_(2.5) were optimized.At the same time,the samples were collected in Beijing for analysis.The results showed that:(1)In order to reduce the Cr background value in the blank filter membrane,the filter membranes were pretreated in 10%nitric acid solution for about 10 hours before sampling,rinsed with ultrapure water,and followed by soaking in 0.12 mol/L sodium bicarbonate solution for about 10 hours.During sample collection process,it is recommended that the optimum temperature for ultrasonic extraction be below 25℃,and the proper storage time of the sample should be less than 29 days.Both of the above can effectively improve the sampling recovery.(2)The IC-ICP-MS method for the determination of Cr(Ⅵ)was optimized with a detection limit of 0.0015 ng/m^(3),a spiked recovery of 92.8%,and an accuracy of 7.8%.Compared with the ion chromatography method,the method established in this study had a shorter detection time and a lower detection limit,which can accurately determine the concentration of Cr(Ⅵ)in atmospheric PM_(2.5).(3)The average concentration of Cr(Ⅵ)in ambient PM_(2.5) in Beijing was(0.095±0.104)ng/m^(3).The study shows that the detection limit(0.0015 ng/m^(3))of the established IC-ICP-MS method for Cr(Ⅵ)is lower than the reference limit(0.025 ng/m^(3))of GB 3095-2012 Ambient Air Quality Standard,and it has better stability in ambient air and meets the requirements for the determination of Cr(Ⅵ)in the domestic ambient air.

关 键 词：六价铬[Cr(Ⅵ)] PM_(2.5) 离子色谱-电感耦合等离子体质谱联用(IC-ICP-MS) 

分 类 号：X513[环境科学与工程—环境工程]