One Fe3O4, two birds: Preconcentration and enhanced photochemical vapor generation for the determination of bismuth by atomic fluorescence spectrometry

Abstract

Fe3O4 was served as an adsorbent and photocatalyst simultaneously in this work, Bi(III) was preconcentrated by Fe3O4 before its photochemical vapor generation-atomic fluorescence spectrometry (PVG-AFS) determination. The experimental conditions including the concentration of formic and acetic acid mixed solution, ultraviolet (UV) irradiation time, the concentration of Fe3O4 and the interferences from the common co-existing ions were explored. The AFS intensity was enhanced slightly by the mixed acid solution (30% (v/v) acetic acid + 5% (v/v) formic acid), while a significant enhancement was observed by using Fe3O4 as photocatalyst with the presence of mixed acid solution, 13-fold enhancement was obtained. The potential enhanced mechanism of Fe3O4 was also discussed here. Fe3O4 was decomposed in the mixed acid solution, Fe3+ was generated and further served as a sensitizer for improving Bi(III) efficiency. Under the optimized conditions, the limit of detection (LOD) of the proposed PVG-AFS system without or with preconcentration (sample of 5 mL) were 0.44 ng/mL and 0.07 ng/mL, respectively. This PVG-AFS system was successfully applied to the determination of four water samples and their spiked samples, with good recoveries ranging from 94% to 104%, demonstrating a good accuracy and applicability.