巯基棉纤维分离、衍生气相色谱法测定痕量砷(Ⅲ)和砷(Ⅴ)

Separation of Arsenic (Ⅲ) and Arsenic (Ⅴ) by Sulfhydryl Cotton Fiber and Determination of Trace Arsenic by Derivative Gas Chromatography

在1mol/L HCl介质中,砷(Ⅲ)能被巯基棉纤维(SCF)吸附、富集,从而与砷(Ⅴ)分离。被吸附的砷(Ⅲ)用热浓盐酸洗脱后,再与二巯基丙醇(BAL)反应形成衍生物,以甲苯萃取,然后用气相色谱法测定。As(Ⅴ)不被SCF吸附,可用KI-硫脲溶液还原为As(Ⅲ),同上法测定。本法干扰很少,检出限达0.01ng(As)。

In a medium of 1 mol/L HCI, As(Ⅲ)can be adsorbed and enriched by sulfhydryl cotton fiber, thus separated from As(Ⅲ). The adsorbed As(Ⅲ) may be leached with warm concentrated HCI, and then converted to its derivative with 2, 3-dimercaptopropanol (BAL). This complex (As-BAL) can be extracted by toluene, and determined by using gas chromatography. The unadsorbed As(Ⅴ)may be reduced to As(Ⅲ) by KI-thiourea solution, and determined by the same method. The detection limit of the method is 0.01ng(As), and a few of interference has been found.