液相色谱—原子荧光联用测定海水中无机砷和有机砷

本文研究并建立了海水中测定砷形态的液相色谱—原子荧光法,进行了实验参数流动相浓度、pH、流速的优化。在优化的实验条件下,采用Hamilton PRP-X100分析柱在6 min内可以完成三价砷、甲基砷和五价砷3种形态的分离、检测。在载流5%HCl,还原剂2%KBH4和0.5%KOH,进样量100μL条件下,三价砷、甲基砷和五价砷检出限分别为0.31μg/L、0.52μg/L和0.36μg/L。在浓度2~80μg/L范围内,3种砷形态均有良好的线性关系,相关系数均优于0.999。用本文所建立的方法进行了海水样品中无机砷和有机砷形态的测试,海水中三价砷、甲基砷的含量较低,五价砷稍高,说明海水中砷形态主要以五价砷存在,当加标量为5~10μg/L时,加标回收率在73%~104%之间。该方法操作前处理简单,灵敏度高、运行费用低廉,适用于海水中砷形态的测试。

Determination of Inorganic and Organic Arsenic in Seawater by Liquid Chromatography-Atomic Fluorescence Spectrometry

A hyphenated technique of liquid chromatography and atomic fluorescence spectrometry was developed for the determination of arsenic species in seawater. The experimental parameters such as mobile phase concentration, pH and flow rate were optimized. Under the optimized experimental conditions, three arsenic species of As(Ⅲ), As(methyl) and As(Ⅴ) can be separated and detected in 6 minutes by using Hamilton PRPX100 analytical column. Under the reaction conditions of carrier flow(5% HCl) and reducer(2% KBH4+0.5%KOH), the injection amount was 100 μL, and the detection limits for trivalent arsenic, methyl arsenic and pentavalent arsenic were 0.31 μg/L, 0.52 μg/L and 0.36 μg/L, respectively. In the range of concentration from 2μg/L to 80 μg/L, there were good linearity among the three arsenic forms, and the linear coefficients were all better than 0.999. The established method was successfully applied to the determination of inorganic and organic arsenic species in seawater samples. The measured concentrations of As(Ⅲ) and As(methyl) were low relatively,and the concentration of As(V) was slightly higher, which indicated that As(V) was the main form of arsenic in seawater. When the adding standard matter amount were 5 μg/L and 10 μg/L, the recoveries were satisfactory(73% ~104%). This method proposed has the advantages of simple sample treatment, high sensitivity, and low operation cost. It is suitable for the determination of arsenic species in seawater.