Amperometric Trace Determination of V(V) and Cr(VI) with Enthanethioic Acid

Abstract

Ethanethioic acid (thioaceticacid, ETA) has been employed for
the amperometric determination of V(V) in 0.1 M KCI and Cr(VI)
in acetate buffer medium of pH 4.99 at d.m.e. While Cr(VI) method
involves no chemical interaction and is based on the phenomenon
of mutual compensation of cathodic current of metal species and
anodic current of ETA, V(V) method seems to be the consequence
of complexation reaction. Metal species-ETA titrimetric ratio has
been found to be 1 : 2 for V(V) and 1 : 3.32 for Cr(VI). Solutions
as dilute as 5.09 ppm [(V(V)] and 0.52 ppm Cr(VI) have been
estimated with high degree of accuracy. Tolerance limits for foreign
ions have also been worked out.