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).

A method for the separation of V(IV) and V(V) in the form of the EDTA complexes using anion chromatography with a Dionex AG5 anion exchange guard column, and the simultaneous determination of V(IV) and V(V) by inductively coupled plasma optical emission spectrometery is described. The interference from other elements is negligible. The detection limits of V(IV) and V(V) were 0.02 mg/l and 0.05 mg/l, respectively, using a glass nebuliser and 2 µg/l for both species by using an ultrasonic nebuliser. The linear range was two orders of magnitude. The method was applied to the analysis of spiked water and industrial samples containing V in different oxidation states.