毛细管电泳紫外吸收法分离检测海洋生物样品中不同形态的砷化合物

Speciation Analysis of Arsenic in Sea Foods with Capillary Electrophoresis-Ultraviolet Detection

本研究建立了对亚砷酸盐As(Ⅲ)、二甲基砷(DMA)、对甲基苯砷酸(p-As)、一甲基砷(MMA)、砷酸盐(As(Ⅴ))5种不同形态的砷化合物的毛细管区带电泳(CZE)分离紫外检测方法,研究了检测波长、缓冲体系种类、pH值及其浓度、分离电压、温度、进样时间等因素对5种形态砷化合物的分离度、灵敏度、重现性等的影响。结果表明,在25℃、195nm、20mmol/LNaH2PO4-5mmol/LNa2B4O7(pH=6.25)缓冲溶液、20kV运行电压、3.0kPa压力进样10s条件下,5种不同形态砷化合物在11min内取得完全分离,5种不同形态砷化合物的迁移时间和峰面积的RSD为0.50%～1.51%和1.65%～3.36%,检出限(3S/N)为0.004～0.30mg/L。本法成功地应用于虾米中不同砷形态含量的测定,其回收率在93%～106%之间。

A capillary zone electrophoresis-ultraviolet detection （CZE-UV） method for the analysis of five arsenic compounds, As （ Ⅲ ） , dimethylarsinic acid （ DMA ） , p-aminophenyl arsenic acid （p-As） , monomethylarsonic acid（MMA） and As（ V ）, in sea foods was described. The optimum conditions of CE determination including detection wavelength, chemical component of buffer solution, pH, buffer concentration, separation voltage and injection time were studied in detail. The results showed that five species of arsenic were base line separated within 11 min under optimum conditions. The relative standard deviations of migration times and peak areas were 0.5% - 1.5% and 1.7% - 3.4% , respectively, and the detection limits were 0. 004 -0.30 mg/L. The method was successfully used to determine different species of arsenic in dried shrimps with recoveries of 93% - 106%.