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.

A new method for vanadium speciation has been developed. The method is based on chromatographic separation of vanadium(IV) and vanadium(V) in acidic medium followed by the determination with ICP-OES. Vanadium species exist in acidic solution (pH < 3) as VO 2+ for vanadium(IV) and VO 2 + for vanadium(V). The two vanadium species were chromatographically separated using a cation exchange column, Dionex IonPack CG10, and eluant (120 mmol/ℓH 2 SO 4 ) at a flow rate of 1.5 mℓ/min. The detection limits for vanadium(IV) and vanadium(V) are 40 µg/ℓand 30 µg/ℓ, respectively. Among common anions, only nitrite, NO 2 -which may act as oxidant for vanadium(IV) and reductant for vanadium(V) can cause interference. Interference from common cations has not been observed for concentration levels not exceeding 40 mg/ℓ. The developed method has been successfully applied to the determination of vanadium(IV) and vanadium(V) in synthetic and minerals processing samples.