钒-5-溴水杨基荧光酮-氯酸盐体系极谱催化波的研究

STUDY ON THE POLAROGRAPHIC CATALYTIC WAVE OF THE REACTION SYSTEM OF V(Ⅴ)-5-Br-SAF-KClO_3

在 p H 4.1的乙酸盐缓冲底液中 ,钒能与 5-溴水杨基荧光酮形成络合物 ,并吸附在汞电极上 ,在氯酸盐存在下 ,在 V( )的电极还原过程中形成催化波。用单扫二阶导数极谱法测定时 ,钒浓度在 1 .0× 1 0 -8～ 1 .0× 1 0 -6mol·L-1范围内与峰高成正比关系 ,检出限为 5.0× 1 0 -9mol·L-1。测得电活性络合物的组成为 V( )∶ 5- Br- SAF=1∶ 1。平行催化反应的速率常数 k=1 .9× 1 0 3(mol· L-1) -1· s-1。

In a base solution of acetate buffer of pH 4.1, a complex is formed between vanadium(Ⅴ) ion and 5 bromo salicyl fluorone (abbreviated as 5 Br SAF) which is adsorbed on the mercury electrode. In the presence of chlorate, a catalytic wave is observed due to the reduction of V(Ⅴ) of the complex at the electrode. By using the single scanning 2nd orde derivative polarographic measurement, a linear relationship between the peak hieghts and vanadium concenteations in the range of 1.0×10 -8 ~1.0×10 -6 mol·L -1 is obtained. The limit of detection is found to be 5.0×10 -9 mol·L -1 . The composition of the electroactive complex is formed haveing a mole ratio of 1 to 1. The reaction rate constant k of the catalytic reaction is found to be 1.9×10 3 (mol·L -1 ) -1 ·s -1 . The method has been applied to the determination of vanadium in water.