Highly efficient photochemical vapor generation of tellurium: effects of antimony and ferric ions

Abstract

In this work, a novel method for the highly sensitive detection of trace tellurium (Te) was developed based on photochemical vapor generation (PVG) coupled with inductively coupled plasma mass spectrometry (ICP-MS). Effects of antimony (Sb) and ferric ions (Fe) on the PVG of Te were reported for the first time. In a medium containing 2% (v/v) acetic acid (AA), 5.0 mg L⁻¹ of Sb(III), and 15.0 mg L⁻¹ of Fe(III), the conversion efficiency for both Te(IV) and Te(VI) was found to be 94% ± 3% upon 90 s of UV irradiation using a thin-film flow-through mercury lamp. The limit of detection (LOD, 3σ, n = 11) was 0.4 ng L⁻¹ for both Te(IV) and Te(VI), which was enhanced about 40 times for Te compared with that obtained using commercial pneumatic nebulization (PN) with ICP-MS. Good precision was achieved, with relative standard deviations (RSDs) of 2.1% and 2.5% for 1.0 µg L⁻¹ Te(IV) and Te(VI) standard solutions (n = 7), respectively. The method was successfully applied to determine trace inorganic Te in three environmental water samples with satisfactory results. Compared with the previous reported PVG systems for Te, the use of organic acids was significantly reduced by more than 10-fold while maintaining high sensitivity. The mechanism of PVG was investigated, and it was found that, in addition to volatile Te, volatile Sb and Sb nanoparticles were generated in this system. This study provides a new perspective for the direct analysis of the total amount of elements in environmental samples and contributes to understanding the interactions between Te, Sb, and Fe during photochemical processes.