Natural mineral assisted photochemical vapor generation for determination of trace inorganic arsenic by inductively coupled plasma mass spectrometry

Abstract

Photochemical vapor generation (PVG) is regarding as an alternative sampling technique of atomic spectrometry, which not only has the advantages of traditional chemical vapor generation (CVG), but also is simple, safe and environmentally friendly. The addition of transition metal ions (such as Fe, Ni, Co, and Cd) can significantly improve the conversion efficiency of elements in PVG and achieve high sensitivity. In this work, the natural mineral (the tailing of vanadic titanomagnetite) is firstly reported as the sensitizer in PVG for highly sensitive detection of elements with inductively coupled plasma mass spectrometry (ICP MS) measurement. As (III) was selected as the analyte. The main factors affecting the photocatalytic activity of the natural mineral and the analytical sensitivity of As(III) were systematically investigated. Under the selected conditions, the analytical sensitivity of the proposed method is about 3 and 4 times higher than that of the ferric ions and the nano-Fe3O4 assisted PVG systems of As(III), respectively. Compared with commercial nano-Fe3O4, the nature mineral shows better stability in PVG medium. In addition, the possible mechanism of the tailing of vanadium titanomagnetite assisted PVG of As (III) was also investigated. It was found that the presence of V and Ti facilitates the photochemical reduction of As. The new finding in this work is important for developing novel catalytical materials in PVG and understanding the environmental impact of the tailings on ecological environment. The proposed method has been successfully applied for the detection of As in natural waters and certified reference materials (GBW 07305a and GBW 07303a).