Vapour generation at a UV/TiO2 photocatalysis reaction device for determination and speciation of mercury by AFS and HPLC-AFS

Abstract

In this study we report a method for direct vapor generation of mercury species on nano TiO₂ under UV irradiation in the presence of a formic acid and sodium formate mixture as a hole scavenger. A novelly designed UV/TiO₂ photocatalysis reaction device (UV/TiO₂ PCRD) was used as an effective sample introduction unit and an interface for mercury species determination by atomic fluorescence spectrometry (AFS) and speciation by HPLC-AFS for the first time. The detection limits of 10, 20, 30 and 70 pg mL⁻¹ of mercury chloride, methylmercury chloride, ethylmercury chloride and phenylmercury chloride, respectively, were achieved by AFS using flow injection mode. Compared with the traditional KBH₄/NaOH-HCl system, UV/TiO₂ PCRD is a superior alternative for online vapor generation of Hg species.