酸性铬蓝K修饰玻碳电极溶出伏安法测定食品中的铅

Determination of Lead in Food by Electrode Stripping Voltammetry with Glassy Carbon Modified by Acidic Chrome Blue K( ACBK)

在含有酸性铬蓝K的pH为7.0的磷酸盐缓冲溶液中,用循环扫描伏安法在玻碳电极表面修饰酸性铬蓝K,制得修饰玻碳电极。应用此修饰电极测定Pb2+时,以HAc-NaAc缓冲溶液为底液,将试液先在-0.8V预还原540s,使Pb2+还原,然后,在-1.0～0.4V电位范围内用示差脉冲伏安法扫描,使铅溶出,根据在-0.6V处铅的溶出峰电流与Pb2+浓度的关系,对Pb2+进行阳极溶出伏安法测定。在最佳实验条件下,Pb2+测定的线性范围为1.43×10-7～1.2×10-5mol·L-1,方法的检出限(3S/N)为1.0×10-8mol·L-1。

A novel polymerized film of acid chrome blue K （ACBK） was prepared on the surface of a glassy carbon electrode （GCE） by cyclic voltammetry （CV） in the phosphate buffer solution （pH7.0） containing ACBK, and then the modified electrode was successfully used to determine Pb2＋. In the HAc-NaAc buffer so- lution （pH4.3） , the test solution was pre-reduction for 540 s at -0.8V, lead was then stripped from the e- lectrode by differential pulse anodic stripping vohammetry in the range from - 1.0V to 0.4V, and the oxida- tion peak potential of lead was observed at - 0.6V. Under the optimum conditions, the calibration curves for Pb2＋ were obtained in the range of 1.43 × 10 -7 - 1.2×10 -5 mol· L-1 respectively. The detection limit （3S/ N） was 1.0×10-8mol· L-1