Slurry sampling thermospray flame furnace atomic absorption spectrometric determination of bismuth in water and geological samples combined with ultrasound-assisted dispersive micro solid phase extraction

Abstract

A new method for the determination of bismuth was established by combining ultrasound-assisted dispersive micro solid phase extraction (UA-DMSPE) with thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) for the first time in this work. Nanometer-sized titanium dioxide (nano-TiO₂) was used as the adsorbent, and the unpacked extraction pattern simplified the operation procedure. The extraction process was assisted by ultrasound. With the application of slurry sampling, the on-line method combining UA-DMSPE with TS-FF-AAS was developed. Problems of nebulization associated with previous methods based on the coupling of FAAS and solid phase microextraction (SPME) were overcome. The combination significantly improved the analytical performance of the modified FAAS instrument. Under the optimal conditions, the limit of detection (LOD) was 0.34 μg L⁻¹, with a sensitivity enhancement factor (EF) of 67. Compared with direct FAAS, the EF was as high as 736. The method was applied to analyze environmental water and geological samples with good agreement with certified values of the standard materials or with values obtained using ICP-MS, which demonstrated its reliability for the determination of traces of Bi in environmental samples. The proposed method provides a promising, simple and low-cost approach to develop a sensitive detection method for Bi based on FAAS.