在线吹扫捕集-气相色谱-原子荧光光谱法测定土壤中甲基汞  

Determination of Methylmercury in Soil Samples with Online Purge and Trap Gas Chromatography-Atomic Fluorescence Spectrometry

作　　者：顾昱晓 孟梅[1] 邵俊娟 史建波[1] 何滨[1] 江桂斌[1] 

机构地区：[1]环境化学与生态毒理学国家重点实验室,中国科学院生态环境研究中心,北京100085

出　　处：《分析化学》2013年第11期1754-1757,共4页Chinese Journal of Analytical Chemistry

基　　金：国家"973"项目(No.2013CB430004);环保公益性行业科研专项(No.201309050)资助

摘　　要：建立了在线吹扫捕集-气相色谱-原子荧光光谱联用测定土壤中甲基汞的方法.土壤样品经KBr/CuSO4溶液提取后,使用二氯甲烷/水萃取与反萃取前处理方法,克服了土壤复杂基质的影响.使用四乙基硼化钠衍生试剂,将甲基汞转化为易挥发的甲基乙基汞,在线吹扫捕集进行富集并进一步消除基体干扰.经条件优化,萃取时间为30 min,反萃取的时间和温度分别为4h和65℃.方法准确、可靠,具有很高的灵敏度.土壤样品检出限可达0.8 ng/g,沉积物标准参考物质ERM-CC580的测定回收率为104％±15％ （n=3）.应用本方法对3种实际土壤样品进行测定,其甲基汞浓度在2.3～5.4 ng/g范围内,加标回收率为87％～ 111％.A method for the determination of trace levels of methylmercury （MeHg） in soil samples with online purge and trap gas chromatography-atomic fluorescence spectrometry （P＆T-GC-AFS） was established. In order to eliminate the influence of complicated soil matrix, the MeHg in soil was firstly extracted with KBr/ CuSO4 solution, and then extracted to dichloromethane and back extracted with deionized water. The ethylation derivatization converted MeHg to the more volatile methylethylmercury, which could be concentrated through online purge and trap system with a further clean-up of matrix. The optimized extraction time was 30 min. The selected time and temperature for back extraction were 4 h and 65 ~C, respectively. The proposed method is accurate, reliable and sensitive. The detection limit for soli sample was 0.8 ng/g. The recovery of the certified reference material （ERM-CC580, estuary sediment） was 104% ＋ 15% （n = 3 ）. The method was applied to analysis of three soil samples, and the concentrations of MeHg were in the range of 2.3-5.4 ng/g with spiked recoveries between 87% and 111%.

关 键 词：甲基汞 土壤 乙基化衍生 气相色谱法 原子荧光光谱法 

分 类 号：X833[环境科学与工程—环境工程] O657.3[理学—分析化学]