Simultaneous speciation of inorganic selenium and tellurium by inductively coupled plasma mass spectrometry following selective solid-phase extraction separation

Abstract

A new method was developed for the simultaneous determination of inorganic tellurium and selenium species in waters by inductively coupled plasma mass spectrometry (ICP-MS) following selective solid-phase extraction (SPE) separation. Under acidic conditions, only selenium(IV) and tellurium(IV) formed complexes with ammonium pyrrolidine dithiocarbamate (APDC), and the complexes were completely retained on a non-polar C₁₈ cartridge. Te(VI) and Se(VI) passed through the cartridge and remained as free species in the solution, thereafter being determined by ICP-MS. Se(IV) and Te(IV) concentrations were obtained as the respective differences between total selenium and Se(VI), and total tellurium and Te(VI) concentrations. The detection limits (3σ) are 7 ng L⁻¹ selenium and 3 ng L⁻¹ tellurium. Factors affecting the separation and detection were investigated. Coexisting ions did not show significant interferences. This method has been successfully applied to the inorganic selenium and tellurium speciation analysis of water samples with spiked recoveries of 82.3–106%.