阴极溶出催化极谱法测定微量硒

DETERMINATION OF TRACE SELENIUM BY CA- THODIC STRIPPING CATALYTIC POLAROGRAPHY

本文提出将溶出伏安法和极谱催化法结合起来,用溶出催化波来测定微量硒;考察了各种试验条件及其它离子对分析结果的影响,并对实样进行了分析测定。用国产883型笔录式极谱仪,配用旋转玻碳电极测定硒,电解富集3—5分钟,可定量测定浓度在4×10^(-9)—1×10^(-7)M范围内的硒;富集20—30分钟,硒的检出下限为7×10^(-10)M。测定时不必除氧。在测定硒的基础上,用玻碳电极和大汞电极相配合,对硒的溶出催化电极过程进行了研究,探讨了此过程中各步反应的机理。

The common electrochemical techniques for determination of trace selenium (Ⅳ) are the stripping voltametry and the one making use of polaro-graphic catalytic wave. We combined this two techniques and established a novel method, cathodic stripping catalytic polarography, for the determination of trace selenium. The various experimental conditions and their influence on the results were studied. The method was applied to the ana-lyisis of some practical samples. By using of a Model 883 polarograph with a rotation glass carbon electrode, after enrichment by electrolysis for 3-5 minutes a concentration in the range of 4×10^(-9)-1×10^(-7)M selenium could be determined or after enrichment for 20-30 minutes a detection limit of 7 ×10^(-10)M selenium was reached. The oxygen in the system was unnecessary to be removed. The electrode process during the stripping catalysis of selenium was also studied with the combination of glass carbon electrode and a bulk mercury. The reaction mechanism involved in this process was discussed.