基于同位镀铋技术的茶叶及其浸出物中铅含量的测定

Determination of Lead Content in Tea and its Extract Based on the Technigue of Situ-plate Bismuth Film

摘要: 以铋膜修饰玻碳电极为工作电极，采用差分脉冲溶出伏安法对茶叶及茶叶浸出物中微量Pb²⁺进行分析。结果表明，Pb²⁺在5~300 μg·L^-1范围内与峰电流呈良好的线性关系，检出限为0.39 μg·L^-1，相对标准偏差为1.98%（n=11），线性方程为I_p=0.023 6ρ（Pb²⁺）-0.098 4，相关系数r=0.999 2，茶叶样品中铅含量为0.53~2.98 mg·kg^-1，加标回收率为91.5%~113.5%；茶叶浸出物中未检出铅，加标回收率在93.6%~99.5%。

Abstract: Bismuth film modified glassy carbon electrode was used for working electrode to determine trace Pb²⁺ in the tea and water extraction by differential pulse stripping voltammetry (DPSV). The results showed that there was a good linear relationship between peak current and concentration of Pb²⁺ in the range of 5-300 μg·L^-1, the regression equation was I_p=0.023 6ρ(Pb²⁺)-0.098 4, and the detection limit was 0.39 μg·L^-1, RSD (n=11) was 1.98% and correlation coefficient rwas 0.999 2. The rang of Pb²⁺ contents in tea was 0.53-2.98 mg·kg^-1. The standard addition recovery for Pb²⁺ in tea and its extraction ranged from 91.5%-113.5% and 93.6%-99.5%, respectively.