Determination of iron(III) and titanium(IV) as their Solochrome Violet RS complexes by constant-current stripping potentiometry: Part 2. Partial least-squares regression calibration procedure for iron(III) and titanium(IV)

Abstract

An automated method for the determination of iron(III)_ and titanium(IV) as their Solochrome Violet RS complexes by constant-current stripping potentiometry and partial least-squares (PLS) regression calibration is described. The multivariate calibration procedure overcomes the problem of completely overlapped titanium(IV) complex and reagent stripping peaks and allows prediction of iron(III) and titanium(IV) concentrations from data obtained under non-linear response conditions. For iron(III), accuracy and precision at the 15 and 65 μg 1−1 concentration levels are 13.2 ± 2.1 mg 1−1 (16%) and 67.5 ± 4.6 mg 1−1 (6.8%), respectively. For titanium(IV) the corresponding values are 14.6 ± 7.3 mg 1− (50%) and 69.5 ± 7.9 (11%). Limitations in the applicability of PLS to electrochemical stripping applications are discussed.