Photochemical Vapor Generation of Tellurium: Synergistic Effect from Ferric Ion and Nano-TiO2

Photochemical vapor generation (PVG) is emerging as a promising analytical tool for Te determination, thanks to its efficient matrix separation, and simple and green procedure. However, the low PVG generation efficiency of Te is the bottleneck for its wide application in environmental samples containing trace Te. Herein, we reported a high efficient PVG for Te determination by synergistic effect of ferric ion and nano-TiO2. The analytical sensitivity was enhanced approximately 15-fold for Te(IV) in the presence of both ferric ions and nano-TiO2, comparing to conventional PVG. Besides, the use of nano-TiO2 can provide Te(VI) and Te(IV) an equal and high PVG efficiency in the presence of ferric ions, owned to the high photocatalytic performance of TiO2 under short-wavelength UV irradiation (254 and 185 nm). Under the optimized experimental conditions, a detection limit of 1.0 ng L-1 was obtained. The precision of replicate measurements was 2.3% (RSD, n = 7) at 0.5 mu g L-1 fig for Te(IV). The methodology was validated by successful determination of Te in surface waters and two standard reference sediment samples. To our best knowledge, this is the first report of the synergistic enhancement of transitional metal ions and nano-TiO2 in PVG, which possesses potential for highly sensitive determination of vapor-forming elements.