A method for the determination of Pb and Cd with trace level by stripping voltammetry on the polyaniline electrode modified with Bi particles was investigated.Various kinds of experimental conditions for the determination of Pb and the deposition of Bi particles on the electrode were discussed.The results showed that a stripping potential peak with high sensitivity about Pb or Cd could be achieved,which was similar to that of the modified electrode.Furthermore,the electrode has shown a high stability and a work curve with a fairly good linearity.Meanwhile,a satisfing analytical result of the Pb concentration with trace level in tap water was achieved.
We Investigated the spectra of Resonance Rayleigh scattering(RRS)for methyl red-heparin system,the spectra characteristics,the primary efiect factors and the optimum condition of the reaction.The resuIts show that the method was based on the discoloration reaction between heparin and methyl red dyes in the pH 6.6 Britton-Robinson solution.The linear range was 0.006μg/mL-4.00μg/mL.The reductiOn in absorbance is directly proportional to the concentration of heparin.and the efiect of surfactants and coexistion substance was investigated.The method has been applied to determine the potency of heparin sodium injection and the heparin sodium in human serum with satisfactory results.
