电化学法测定青椒中重金属镉

Analysis of cadmium in green peppers by electrochemistry

目的 建立电化学法测定青椒中镉的最佳方法.方法 用硫酸一过氧化氢消解法处理样品,用线性扫描溶出伏安法对青椒中镉进行测定,最佳的电化学参数为：起始电压为-1.2V,终止电压为-0.2V,富集时间为120 s,缓冲溶液为醋酸钠（1 mol/L）一氯化钠（0.2 mol/L）.结果 测定的镉含量在0.1～～0.9 μg/mL浓度范围内呈良好线性关系,相关系数为0.999 1,检出限为0.01 μg/mL,测定的相对标准偏差为0.97％,回收率在98.62％～～ 101.10％.结论 该方法操作简单,准确度好,灵敏度高,能够满足测定的要求.

Objective To establish an optimum electrochemical method for the determination of Cadmium（Cd） in green pep- pers. Methods The sample was treated with sulfuric acid-hydrogen peroxide resolution, Cd contained in green peppers was determined by linear sweep voltammetry; the optimum electrochemical parameters are： initial voltage was --1.2 V, termination roltage was -- 0.2V; accumulation time was 120 second ; buffer solution was sodium acetate（ 1 mol/L）-sodium chloride （0.2 tool/L）. Results The peak current was proportional to Cd concentration in the range of 0.1 % 0.9 %tg/mL; the correlation was 0. 999 1 % the detection limit was 0.01μg/mL; the relative standard deviation was 0.97 % ; the recovery ratio was from 98.62 % to 101.10%. Conclusion The method is simple, accurate, highly sensitive and can satisfy the Cd analysis.