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

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.