Indirect Determination Of Trace Bismuth(â…¢) By Dual-wavelength Catalytic Kinetic Spectrophotometry

Build on the catalytic effect of Cu(Ⅱ)on the combustion of indicators in thedual-indicator reaction system, and the quantitative replacement of Cu(Ⅱ) by fromCu-EDTA, several new dual-indicator catalytic reaction system for the determination ofBi(Ⅲ) were been studied. The dual-indicator system’s reaction rate was direct proportionalto thickness of catalysts and the determination susceptivity was better than single-indicatorsystem. By means the influence of optimum reaction medium, the dosage of reagent,reaction time and temperature on the reaction rate of research, working curve was designedfinally.The paper’s research contents mainly include:1、 In dilute sulfuric acid medium, Bi(Ⅲ)can be used to replace the Cu(Ⅱ) inEDTA-Cu(Ⅱ), and Cu(Ⅱ) on the reduction reaction of hydrogen peroxide with methylgreen and neutral red oxidation with catalytic activity, by measuring the absorbance at535nm and627nm wavelength, a dual wavelength indicator catalytic kineticspectrophotometric method for the indirect determination of bismuth in drugs andnew method. The linear range was0.00200~0.110μg/25mL, the detection limit is4.1×10-11g/mL. For the determination of bismuth in medicine, with satisfactory results.2、In the medium of H2SO4, The quantitative replacement of Cu(Ⅱ) by Bi(Ⅲ) fromCu-EDTA and the concentration of Cu(Ⅱ) have a quantitative relationship betweenreaction with the catalytic oxidation of hydrogen peroxide while the faded toluidine blueand neutral red. Through respective detection of absorbance at wavelength524nm and630nm, a new method for dual-wavelength catalytic kinetic spectrophotometry indirectdetermination of Bi(Ⅲ) has been developed. Thelinear range was0.00200~0.0220μg/25mL and the detection limit was8.9×10-11g/mL. The method was applied to thedetermination of Bi(Ⅲ) in medicaments with satisfactory results.3、The indirect determination of Trace Bismuth herbs contain through the study of thekinetics of catalytic. Try the indicator, EDTA, hydrogen peroxide and dilute sulfuric acidfor the determination of bismuth and the amount of copper in experimental conditions andchange. Taking into account the effects of coexisting ions on the experimental system in the end of the experiment, the experiment of the linear range was0.00200~0.0160μg/25mL and the detection limit is2.4×10-10g/mL. Finally, find out the best conditions forthe detection of experiment and application of Trace Bismuth in the herbs, with satisfactoryresults.4、For study only in dilute sulfuric acid medium, Bi(Ⅲ)can be quantitativelyreplacing the Cu(Ⅱ) in EDTA-Cu(Ⅱ), and Cu(Ⅱ) reaction effect concentration andhydrogen peroxide oxidation together make ethyl violet and neutral red fade with thequantitative relationship, by measuring absorbance wavelength at535nm and627nm, adual wavelength catalytic kinetic spectrophotometric method for the indirect determinationof bismuth in drugs of new method. The linear range was0.00100~0.00900μg/25mL, thedetection limit is1.6×10-10g/mL. For the determination of bismuth in medicine, withsatisfactory results.The result of researchs shows that dual-wavelengths and dual-indicator catalyticdynanics ectrophotometry method’s susceptivity, selectivity and the detection range wereall better than single indicator systems. Dual-indicator system improved the dynamicsanalysis method.