丁二酮肟修饰碳糊电极阳极溶出伏安法测定痕量铋

Anodic Stripping Voltammetric Determination of Bismuth with Diacetyldioxime-modified Carbon Paste Electrode

报道了用丁二酮肟修饰碳糊电极测定微量铋的电分析方法。Bi^(3+)通过与电极表面的丁二酮肟作用而富集在电极表面,同时在-0.40 V(vs.SCE)还原成零价,当电极电势从-0.40 V向0.40 V扫描时,被还原的铋从电极表面溶出,在0.03 V出现一个十分灵敏的阳极溶出峰。优化了各种实验参数,如支持电解质的选择及pH值、丁二酮肟的用量、富集电位及时间等。修饰电极测定铋的线性范围为1×10^(-9)～1×10^(-6)mol/L。富集6 min后检出限可达4×10^(-10)mol/L。该方法简便快速,灵敏度高,分析成本低廉,并成功应用于实际水样中微量铋的测定。

A simple and reliable electrochemical method for the determination of bismuth by using diacetyldioxime-modified carbon paste electrode was described. Bi^(3+) is preconcentrated on the surface of the diacetyldioxime-modified carbon paste electrode, and then reduced at—0. 40 V. After that, the reduced bismuth was stripped from the electrode surface during the positive potential sweep from—0.40 V to 0.40 V, and a well-defined stripping peak at 0. 03 V appeared. The stripping peak current was proportional to the concentration of Bi^(3+) from 1×10^(-9) mol/L to 1×10^(-6) mol/L. The detection limit (signal-to-nois=3) was 4×10^(-10) mol/L after 6 min accumulation. The proposed method was successfully applied to the determination of bismuth in water samples.