STUDY ON THE POLARAGRAPHIC ADSORPTION WAVE OF THE COMPLEX OF MOLYBDENUM(Ⅵ)-CALMAGITE AND ITS ANALYTICAL APPLICATION

In an acetate buffer solution of pH 4.0,a fine polarographic adsorption wave was produced by the complex of Mo(Ⅵ) and calmagite at dropping mercury electrode,with its peak appeared at -0.66 V(vs.SCE).Under optimum condition,linear relationship between the 2nd derivative of peak current (I″p) and the concentration of Mo(Ⅵ) was obtained in the range of 5.0×10-8-1.2×10-5mol·L-1 (r=0.999 7).Detection limit (n=8) of the method was found to be 5.0×10-9mol·L-1 for Mo(Ⅵ).The proposed method has been applied to the determination of molybdenum in some legume samples,giving RSD′s less than 5% and recoveries in the range of 972%-102.0%.The complexing mole ratio between Mo(Ⅵ) and calmagite was found to be 1 to 2.The electrochemical behavior of the polarographic wave was also studied.