金在脱乙酰壳多糖化学修饰电极上的电化学行为及分析应用

Electrochemical Behaviour of Au(Ⅲ) at Glassy Carbon Electrode Modified by Chitosan and Its Application

用脱乙酰壳多糖化学修饰电极为工作电极，阳极溶出伏安法测定痕量金。在ｐＨ１～２的ＫＣｌ－ＨＣｌ底液中，起始电位０．２０Ｖ，终止电位１．３０Ｖ，富集时间５ｍｉｎ，以０．１Ｖ／ｓ扫速阳极溶出，峰电位在１．００Ｖ（ｖｓ．ＳＣＥ），Ａｕ（Ⅲ）浓度在０．１０ｍｇ／Ｌ～１０ｍｇ／Ｌ范围内与峰高呈线性关系。在富集１０ｍｉｎ时，可检测０．０２５ｍｇ／ＬＡｕ，大大提高了测定灵敏度，用于矿样测定，无需分离，结果满意。用紫外光谱和拉曼光谱研究了该法的电极过程机理。

A chitosan containing glassy carbon electrode was found to give highly sensitive voltammetric wave for Au(Ⅲ) HCl KCl system by anodic stripping voltammetry. In a solution of 0.1 mol/L HCl KCl(pH 2.0) , deposited at 0.0V for 5 min ,with scan rate of 0.1 V/s , the peak current is proportional to the Au(Ⅲ) concentration between 0.01～1.0 mg/L,r=0.9983 and 1.0￣10 mg/L ,r=0.9996. 0.025 mg/L Au(Ⅲ) was determined by deposition for 10 min. The method was fairly free from interference and could be applied to the determination of gold in precious metal ores . The possible mechanism of electrochemical reaction has been proposed by the study of CV , UV and FT-Raman spectrometry