铑(Ⅲ)与5-(5-氯-2-吡啶偶氮)-2,4-二氨基甲苯的配合物催化氢波研究

Studies on the Catalytic Hydrogen Wave of Rhodium Complex with 5-(5-Chloro-2-pyridylazo)-2, 4-diaminotoluene

本文建立了一种催化极谱法测定痕量铑的新方法.先使铑(Ⅲ)与5-Cl-PADAT在pH5的HOAc-NaOAc缓冲溶液中生成稳定的配合物,再于适量HClO_4底液中进行极谱测定.并研究了影响极谱催化波的各种因素及波的性质,确定该波为铑(Ⅲ)与5-Cl-PADAT配合物的催化氢波,提出了可能的电极过程,并进行了实验验证.该法测定铑的线性范围为3.9×10^(12)—3.9×10^(-9)mol·dm^(-3),检出限为1.9×10^(-12)mol·dm^(-3).已应用于镍基合金及催化剂中铑的测定.

In this paper, a new superhigh sensitive analysis method determining rhodium by catalytic polarography was established. Rhodium first reacts with 5-Cl-PADAT to form a stable complex in a buffer solution of pH 5 HOAc-NaOAc, then, a polarogram was recorded in media of HC1O_4. The optimum analysis conditions were determined through investigating various influences on the catalytic wave. Characteristics of the wave were also researched and it is proved that the wave is a catalytic hydrogen wave of the complex of rhodium with 5-Cl-PADAT. A probable electrod mechanism was proposed and was verified experimentally. The linearity range of rhodium concentration is 3.9×10^(-12) to 3.9×10^(-9) mol·dm^(-3), the detection limit is 1.9 x 10^(-12)mol·dm^(-3). The method has been applied to the determination of rhodium in nickle base alloy without any chemical separation, and a satisfactory result was obtained.