活化玻碳电极伏安法测定锰的研究

Voltammetric determination of manganese by using active glassy carbon electrode

采用活化玻碳电极(GC)以伏安法对测定锰进行了研究。结果表明:沉积于电极表面的二氧化锰对锰(Ⅱ)的电化学氧化具有自催化作用,活化GC电极可极大地提高测定锰的灵敏度。在0.04mol LNH3 NH4Cl(pH9.0)底液中,锰浓度在6.0×10-8～1.0×10-5mol L范围内成线性关系,检出限为4.0×10-8mol L。用3×10-7mol L锰溶液重复测定9次,RSD为1.6%。

The determination of manganese(Ⅱ) by linear sweep voltammetry at pretreated glassy carbon (GC) electrode was investigated. The electrochemical oxidative process of Mn(Ⅱ) was catalyzed by MnO_2 deposited on the surface of the GC electrode. The sensitivity of the manganese determined by the voltammetry was greatly enhanced at active GC electrode. In 0.04 mol/L NH_3-NH_4Cl(pH 9.0)buffer solution, the anodic current was linearly proportional to the concentration of Mn(Ⅱ) in the range of 6.0×10^(-8)～1.0×10^(-5) mol/L. The detection limit was 4.0×10^(-8) mol/L. The relative standard deviation was 1.6% (n=9) at 3×10^(-7) mol/L level.