碳糊电极上吸附伏安法测定痕量钪的研究

Studies on Adsorptive Voltammetric Determination of Trace Scandium at a Carbon Paste Electrode

研究了钪(Ⅲ) 茜素氨羧络合剂(ALC)络合物在碳糊电极正电位区的吸附伏安行为,利用该络合物产生的二次导数吸附氧化峰电流与钪浓度成正比测定钪。其线性范围为2.0×10-9～6.0×10-7mol/L;富集120s,检出限达1.0×10-9mol/L(S/N=3)。探讨了电极反应机理。在同一支电极同一表面上15次连续测定4.0×10-8mol/L的Sc(Ⅲ),方法的相对标准偏差为3.7%。该法用于矿石样品中钪的测定,结果满意。

The adsorptive voltammetric behavior of the scandium(Ⅲ)-alizarin complexon(ALC) complex was investigated in the positive potential region of a carbon paste electrode (CPE). The concentration of scandium was directly proportional to the second-order derivative oxidation peak current of the Sc(Ⅲ)-ALC complex over a range of 2.0×10^(-9)～6.0×10^(-7) mol/L. The detection limit was as low as 1.0×10^(-9) mol/L (S/N=3) for 120 s accumulation times. The relative standard deviation was 3.7% for 15 successive determinations on the same electrode surface at the 4.0×10^(-8 )mol/L level. The electrode processes of the adsorbed complex were proposed. The method has been applied successfully for the determination of scandium in ore samples.