镓Ⅲ-茜素氨羧络合剂在碳糊电极上的阳极吸附伏安法研究及应用

Studies on Anodic Adsorptive Stripping Voltammetry of Gallium Ⅲ-Alizarin Complexone at Carbon Paste Electrodes and Its Application

研究了镓 茜素氨羧络合剂 (ALC)在碳糊电极上的阳极吸附伏安行为 ,并以此建立了一种高灵敏度、高选择性测定镓的吸附伏安法。在 0 .1 2mol LHAc NaAc 0 .2 4mol L邻苯二甲酸氢钾底液 (pH 4.5 )中 ,-0 .1 0V (vs.SCE)富集 90s(或 1 80s) ,以 2 5 0mV s扫速线性扫描至 0 .90V ,Ga3+ ALC在碳糊电极上产生灵敏的与ALC的峰电位相差近 2 3 0mV的吸附氧化峰 ,其二次导数峰电流与镓浓度在 5 .0× 1 0 - 1 0 ～ 8.0× 1 0 - 7mol L范围内呈线性关系 ;富集 2 40s检出限达 3 .0× 1 0 - 1 0 mol L(S N =3 )。探讨了电极反应机理。该法用于粮食样品中镓的测定 ,结果满意。

The anodic adsorptive voltammetric behaviour of gallium ? -alizarin complexone (ALC) system at a carbon paste electrode (CPE) was investigated. A sensitive well-defined anodic adsorptive peak of the complex of gallium ? -alizarin complexone was obtained at potential of 0.78 V ( vs .SCE) by using linear-scanning voltammetry in a supporting electrolyte of 0.12 mol/L HAc-NaAc and 0.024 mol/L potassium biphthalate (pH 4.5). Under optimum conditions the concentration of Ga ? was proportional to its second-order derivative peak height over a range of 5.0×10 -10 ～8.0×10 -7 mol/L. The detection limit was found to be 3.0×10 -10 mol/L with 4 min accumulation. The electrode processes of the complex were presented. The proposed method was applied successfully to the determination of gallium in food samples.