阳极溶出方波伏安法测定食醋的痕量铅

Determination of Trace Lead in Vinegar by Anodic Stripping Square Wave Voltammetry

运用阳极溶出方波伏安法对食醋中的有毒元素铅含量进行了测定。Pb2 + 在pH =4.7的HAc -NaAc缓冲溶液中 ,于-0 .45V(vs.SCE)左右出现一灵敏的方波伏安溶出峰 ,铅离子浓度在 1.0× 10 - 6 ～ 5 .0× 10 - 4 mol·L- 1 范围内与峰电流成良好的线性关系 ,该方法的回归方程为 :ip(αA) =1.2 75× 10 5 C + 0 .0 98(c :mol·L- 1 ) ,相关系数r =0 .996 2。方法能有效的消除共存元素的干扰 ,回收率为 98.1%～ 10 2 .0 %。

The electron-chemical behavior of Pb 2+ has been studied,and an anodic stripping square wave voltammetry method for the determination of Pb 2+ was established.In a buffer solution of HAc-NaAc(pH=4.7),Pb 2+ ions produced a good peak at -0.45V(vs.SCE).There was a good linear relationship within the range of 1.0×10 -6 ～5.0×10 -4 mol·L -1 .The method was rapid,simple and accurate,and can be used for the determination of trace lead in vinegar.It was effective in eliminating of interference for common existing elements.The recovery of lead was 98.1%～102.0%.