差分脉冲溶出伏安法测定茶叶中的痕量铅

Determination of Trace Lead in Tea by Differential Pulse Stripping Voltammetry

提出了一种测定茶叶中痕量铅的新方法。在0．1 mol／L HCl底液中,以银基汞膜电极为工作电极,采用差分脉冲溶出伏安法测定了茶叶中的铅含量,并优化了实验条件。结果表明,铅的峰电流与其质量浓度在0．1-15 μg／mL范围内有良好线性关系,回归方程为I=80．46C+6．794(J:μA,C:μg／mL),相关系数R=0．997 8,最低检出限为0．01μg／mL。用国家标准茶叶对此方法的准确性进行了验证,测定结果与标准值相符。该方法简单、快速,测定干扰小,灵敏度高,用于茶叶中痕量铅的测定,结果满意。

A new method of determination of trace lead in tea has been developed. The content of lead was determined in 0. 1 mol/L HCl by differential pulse stripping voltammetry using thin film mercury on silver electrode as working electrode, and optimized the experiment conditions. The results showed that the peak current is well-proportioned to the concentration of lead in the range of 0.1-15μg/mL, the regression equation is I=80.46C＋6. 794 （I：μA, C： μg/mL）, the correlation coefficient is 0. 997 8, and the detection limit is 0. 01μg/mL. The veracity of this method was validated by determination of the standard tea, and the content of lead is in good agreement with the standard value. The new method introduced is simple and convenient with high sensitivity and little interference. It can be adapted to the determination of trace lead in tea with satisfactory results.