Speciation of vanadium by anion-exchange chromatography with inductively coupled plasma mass spectrometry and confirmation of vanadium complex formation using electrospray mass spectrometry

Abstract

Inductively coupled plasma mass spectrometry (ICP-MS) and electrospray mass spectrometry (ESI-MS) were used as complementary techniques to identify vanadium–EDTA complex formation. ESI-MS enabled the identification of the 1:1 stoichiometry of [VO(EDTA)]²⁻ and [VO₂(EDTA)]³⁻ and their MS spectra showed these vanadium complexes to be present in the solution. In addition, on-column complex formation of vanadium with ethylenediaminetetraacetic acid (EDTA), and the subsequent separation and detection of their complexes, was achieved by ion chromatography (IC) with ICP-MS. To avoid polyatomic ions such as ³⁵Cl¹⁶O⁺ interfering in the detection of ⁵¹V, anion-exchange chromatography was used to separate chloride from vanadium–EDTA complexes with an eluent containing 30 mM NH₄H₂PO₄ and 5 mM EDTA at pH 8.0 within 15 min. Linear plots were obtained in a concentration range of 2.0–500 μg L⁻¹ with detection limits from 0.5–1.0 μg L⁻¹. Finally, the proposed method was used for the determination of vanadium species in contaminated water.