Photocatalytic preconcentration of Bi on TiO2 nanoparticles

Abstract

Titanium dioxide nanoparticles (NP-TiO2) are implemented for the dispersive micro-solid phase extraction of Bi by photocatalytic adsorption by UVA irradiation (365 nm) in the presence of ethanol as a sacrificial agent. The determination of bismuth was carried out by electrothermal atomic absorption spectrometry. The optimization stage was performed using the response surface method, implementing a Box-Behnken design. The proposed methodology does not require pH conditioning of the sample for Bi adsorption on NP-TiO2. The procedure reached limits of detection and quantification of 0.5 and 1.6 ng L−1 respectively. The relative standard deviation was 8.3% for a Bi solution of 50 ng L−1, with a preconcentration factor of 20 when 20 mL of sample were treated with 30 mg of NP-TiO2 and eluted with 1 mL of HNO3. The method was applied to the determination of Bi in digested copper ore samples, obtaining quantitative recoveries.