毛细管电泳-电感耦合等离子体质谱法测定藻类中6种不同形态的砷化合物

摘要

建立了一种利用毛细管电泳与电感耦合等离子体质谱联用技术(CE-ICP-MS)分析检测6种不同形态砷化合物的方法.详细研究了缓冲溶液的种类、pH值和浓度,分离电压以及进样时间等因素对6种砷化合物的分离度、灵敏度和重现性等的影响.结果表明,在最佳条件下,三价砷(As3+)、一甲基砷(MMA)、二甲基砷(DMA)、五价砷(As5+)、砷胆碱(AsC)和砷甜菜碱(AsB)6种化合物在25 min内得到完全分离.6次平行测定中,6种砷化合物峰面积的相对标准偏差(RSD)为3%～5%,检出限(以As计)(3倍信噪比)为0.08～0.12μg/L.应用该方法成功地对海带中6种砷化合物进行了分析,回收率为90%～103%.该方法具有耗时短、灵敏度高、样品消耗量少、稳定性好等优点,可用于藻类样品中不同形态砷化合物的分析.%A method for the detection of trace As( Ⅲ ). As( Ⅴ ), monomethylarsonic acid ( MMA ), dimethylarsinic acid ( DMA ), arsenocholine ( AsC ) and arsenobetaine ( AsB ) in seaweeds by capillary electrophoresis-inductively coupled plasma mass spectrometry ( CE-ICP-MS )was developed. The optimized conditions of CE including chemical component, pH and concentration of the buffer, separation voltage and injection time were studied in detail. The results showed that the above six species of arsenic were baseline separated within 25 min under the optimized conditions. The relative standard deviations ( n =6 ) of the peak areas were smaller than 5％. and the detection limits ( calculated as As ) ( S/N =3 ) were 0.08 -0.12 μg/L for all the above six species of arsenic. The method has been successfully applied to the determination of the species of arsenic in kelp samples. The recoveries were 90％ - 103％. The method has good reproducibility, high sensitivity, short analytical time and strong resistance to complex matrix. and can be used for the speciation analysis of arsenic in real seafood samples.