TOPO化学修饰碳糊电极阴极伏安法测定金

VOLTAMMETRIC DETERMINATION OF TRACE AMOUNT OF GOLD WITH TOPO—CHEMICALLY MODIFIED CARBON PASTE ELECTRODE

本文研究了TOPO—化学修饰碳糊电极测定金。在不加电压情况下于0.1～1.0mol·L-~1HCl介质中进行化学富集,+0.6V～-0.1V范围阴极扫描,+0.20V出现的还原峰高与金浓度0.4～1000ng.ml^(-1)范围内成线性关系。改换底液溶出时,铁允许量可达10000倍而不干扰金的测定。用于合金样品中金的测定,结果满意。并讨论了电极反应的机理。

The voltammetric determination of gold (Ⅲ) with TOPO-chemically modified carbon paste electrode (CMCPE) is studied. First. gold is accumulated on CMCPE in 0. 1-1 mol. L^(-1)HC1 solution without the application of any potential to cell. and then, the current is recorded while a potential is applied and scanned cathodically from 0. 6-0.10V (vs. SCE). The response deponds on the concentration of gold in the solution. prcconcentration time and other parameters. Detection limit is 0.1ng. ml^(-1). A linear range between the concentration of gold from 0.4ng. ml^(-1) to 1000ng. ml-1 and the peak height is observed. The electrode has excellent stability and reproducibility. If the medium is exchanged before the preconcentrated gold is reduced, Fe(Ⅲ), 1000 fold by weight more than gold, present in the sample docs not interfere with the determination. Discussion on the behavior of gold (Ⅲ) in CMCPE is given. The method is of utility for the determination of gold in metallurgical product with satisfactory results.