4-(3-吡啶基)-2-巯基咪唑修饰碳糊电极阳极溶出伏安法测定痕量银

报道了采用化合物4-(3-吡啶基)-2-巯基咪唑(PMI)修饰碳糊电极测定痕量银的阳极溶出伏安法。在0.1 mol/L的HNO3中,Ag+可以富集于PMI修饰电极表面,将介质交换至含I-的0.02 mol/L硫酸溶液中,-0.20 V还原30 s后再进行阳极溶出伏安测定,可以获得灵敏的银阳极溶出峰。一次导数峰电流与Ag+在8.0×10-10~4.0×10-6mol/L浓度范围内呈线性关系,检出限可达5.0×10-10mol/L(S/N=3)。采用本法不经过预分离,对成分复杂的定影液废液和锌合金等样品进行了直接测定,测定的回收率为92%~105%。

Determination of trace silver by anodic stripping voltammetry with a 4-(3-pyridyl)-2-mercapto imidazole modified carbon paste electrode

The determination method of trace silver by anodic stripping voltammetry with a 4-(3-pyridyl)-2-mercapto imidazole (PMI) modified carbon paste electrode was reported in the present study. In 0.1 mol/L HNO_3, Ag~+ could be enriched on PMI to modify electrode surface. The medium was exchanged to 0.02 mol/L H_2SO_4 containing I~-. Silver was determined by anodic stripping voltammetry after being reduced at -0.20 V for 30 s, and sensitive anodic stripping peaks of silver could be obtained. The first order derivative peak current showed linear relationship with Ag~+ in the range of (8.0×)10~(-10)- 4.0×10~(-6) mol/L. The detection limit was up to 5.0×10~(-10) mol/L (S/N=3). This method has been applied to the direct determination of waste fixative and zinc alloy without pre-separation. The recovery was 92%-105%.