络合吸附极谱波测定痕量钼

Polarographic Determination of Traces of Molybclenum(Ⅵ) by the Adsorptive Wave of the Complex of Mo(Ⅵ) with Alizarin

摘要: 在0.05 mol·L-1 HOAc-NaOAc(pH 4.74)介质中,Mo(Ⅵ)-茜素络合物在二阶导数极谱图上产生良好的吸附还原波,从而建立了络合吸附极谱法测定痕量钼的方法,其峰电位约为-0.32 V(vs.SCE).其峰电流(I″p)与Mo(Ⅵ)浓度在8.9×10-8~2.4×10-6mol·L-1范围内呈线性关系,检出限为7.0×10-9mol·L-1.应用该法测定了茶叶、人发中痕量钼,测得回收率在98%~104%之间.研究了络合物的组成和极谱波的性质.

Abstract: In an acetate buffer medium of pH 4.74,a sensitive polargoraphic-adsorptive-reductive wave was observed produced by the complex of Mo(Ⅵ) with alizarin,with its peak potential at -0.32 V (vs.SCE).Linear relationship between the values of 2nd derivative of it peak current (I″p) and concentration of Mo(Ⅵ) was found in the range of 8.9×10-8~2.4×10-6mol·L-1,with a detection limit of 7.0×10-9mol·L-1.Based on these facts,a sensitive polarographic method for determination of traces of molybdenum was proposed.In its application to the analysis of samples of tea and human hair,values of recovery found were in the range of 98%-104%.The composition of the complex and the characteristics of its polarographic wave were also studied.