LINEAR-REGRESSION ANALYSIS OF POTENTIOMETRIC TITRATION DATA FOR ASYMMETRIC REDOX REACTIONS

A statistical method is proposed for treating potentiometric titration curves for homogeneous asymmetric redox reactions. The method is base d on the use of a mathematical model for the transformation of the bra nch of a titration curve in the region of potentials of a reversible r edox couple into a linear regression characteristic whose slope numeri cally coincides with the equivalent titrant volume to an accuracy of t he LS estimation. The method was verified in the model titrimetric sys tem Mohr's salt-K2Cr2O7 and used for determining tellurium in an indiv idual solution, in a semiconductor CdTe alloy, and in a CdTe ceramic. The random error in the estimation of the equivalence point by the dat a of a separate titration of 0.1-0.01 M solutions does not exceed 0.3% . In the case of titration of a 0.001 M solution, this error increases to 1.2%. The value of RSD varies from 0.06 to 0.7%.