Study and Application of Adsorptive Catalytic Wave Produced by the Reaction System of Bi(Ⅲ)-Rutin-K2S2O8

In a NaOAc-HOAc buffer solution of pH 4.6, the complex formed between Bi(Ⅲ) and rutin gave an adsorptive polarographic wave at the potential of -0.28 V (vs.SCE), the peak current of which was increased upon the addition of K2S2O8. Values of 2nd derivative of the peak current were found to keep linear relationship with the concentration of Bi(Ⅲ) in the range of 1.0×10-8-1.5×10-6mol·L-1, with its detection limit (3S/N) of 7.0×10-9mol·L-1. The adsorptive and catalytic properties of the polarographic wave were proved by results of electrochemical study. The proposed method was used in the analysis of colloidal bismuth pectin sample for its Bi(Ⅲ) content, giving results in consistency with the labelled value. Tests for recovery were carried out by addition of Bi(Ⅲ) standard solution to the pectin sample as matrix, values of recovery found were ranged from 95.5% to 101.1%.