A computer-based method is proposed for data processing in the successive potentiometric precipitation titration of a three-component mixture of differently charged ions. It is based on a piecewise transformation of the titration curve into linear regression characteristics, the parameters of which determine the successive equivalence points and the solubility products of the precipitates formed in the course of titration to the accuracy of least-squares estimates. To implement the calculation algorithm, a DIFTITR2 program written in Turbo Pascal was developed. The method was tested on the titration of an artificial solution containing a mixture of Cd(II), Hg(II), and Te(IV) with diethyldithiocarbamate, using a chalcogenide Cd-selective or a glassy-carbon indicator electrode, and was used for the analysis of the main components in a semiconductor material, namely, a solid solution of mercury and cadmium tellurides. For concentrations of test ions in the model solution from 7.5 × 10-3 to 3 × 10-4 M, the RSD value varies from 0.01 to 0.3; the determination error does not exceed 6%. The RSD value for the semiconductor alloy lies in the range of from 0.002 to 0.01.
ASJC Scopus subject areas
- Analytical Chemistry