巯基棉分离吸附溶出伏安法测定茶叶及茶汤中痕量砷

Separation of Arsenic(Ⅲ) and Arsenic(Ⅴ) by Sulfhydryl Cotton Fiber and Determination of Trace Arsenic in Tea andTea Soup by Adsorptive Stripping Voltammetry

本文研究了巯基棉纤维（ＳＣＦ）对Ａｓ（Ⅲ）和Ａｓ（Ⅴ）的吸附性能，建立了ＳＣＦ分离Ａｓ（Ⅲ）和Ａｓ（Ⅴ）吸附溶出伏安法测定生物样品中痕量砷的方法。结果表明：在１ｍｏｌ／Ｌ盐酸介质中，ＳＣＦ可定量吸附Ａｓ（Ⅲ），Ａｓ（Ⅴ）不被吸附；用ＫＩ－（ＮＨ２）２ＣＳ预先还原Ａｓ（Ⅴ），通过ＳＣＦ分离，可消除干扰离子对测定砷的影响。方法用于测定桃叶、煤飞灰及番茄叶标样中的砷，其结果与标准值相符；应用此法还测定了几种茶叶及茶汤中的痕量砷和不同价态的砷，结果令人满意。

In a medium of 1 mol/L HCl,As(Ⅲ) can be adsorbed and perconcentrated by sulfhydryl cotton fiber(SCF),thus separated from As(Ⅴ):As(Ⅴ) can be reduced to As(Ⅲ)with KI-thiourea solution.Interferences can be removed.The adsorbed As(Ⅲ) may be leached with warm concentrated HCl,and determined by using adsorptive stripping voltammetry.this method has been applied to the determination of trace arsenic in tea and tea soup with satisfactory results.