Simultaneous separation and determination of Tl(I) and Tl(III) by IC-ICP-OES and IC-ICP-MS

Abstract

A new hyphenated method was developed for the speciation of Tl. In this method, Tl(III) was complexed with DTPA to form a Tl(III)-DTPA anionic complex. Tl(I) did not form a complex with DTPA. The two species were separated simultaneously by means of ion chromatography using a Dionex cation exchange guard column, CG12A, and 15 mmol/ℓ nitric acid as eluant. When ICP-OES was used as detector the detection limits for both species were 0.8 mg/ℓ for an inert V-groove nebuliser and 0.1 mg/ℓ for an ultrasonic nebuliser. No spectral interference was observed but high concentrations of metals such as Fe and Al could lead to broadening of the Tl(I) peak. It was demonstrated that the same chromatographic method can be used with ICP-MS detection. Detection limits were then reduced to 25 ng/ℓ for Tl(I) and 70 ng/ℓ for Tl(III).


Water SA Vol.29(1) 2003: 17-22