Application of a dioxime-PVC electrode to potentiometric studies of Cr(III) ion

A PVC membrane Cr(III) ion selective electrode has been constructed using 2H-1,4-benzothioazine-2,3(4H)dione dioxime (BTD) as membrane carrier. The influence of membrane composition on the electroderesponse was studied. The electrode exhibits a Nernstian response over a Cr(III) concentration range of 1.0 x10 6 to 1.0>< 10-1 M (r = 0.99) with a slope of 19.5 ± 0.5 mV per decade of concentration, and a detection limitof 8.9 x le M. The selectivity coefficient values as determined by separate solution method (SSM) indicateexcellent selectivity for Cr(III) ion over a large number of other ions. Applications of the proposed electrode tothe determination of Cr(III) in real samples and as an indicator for potentiometric titration of Cr(III) ion withEDTA, are reported.