Speciation of chromium in beverages and seasoning samples by magnetic solid-phase extraction and microsample injection system flame atomic absorption spectrometry

摘要

In this research, a magnetic solid phase extraction based on the use of magnetic polyaniline-polythiophene copolymer (Fe3O4@coPANI-PTH) nanoparticles is applied for chromium speciation from water, beverages and seasoning samples followed by microsample injection system-flame atomic absorption spectrometry(MIS-FAAS) analysis. The selective adsorption of Cr(III) in presence of Cr(VI) by Fe3O4@coPANI-PTH in the pH range of 9.0-10.5 was obtained and the total Cr, after reduction of chromium(VI) to chromium(III) by adding 0.5 mL of concentrated H2SO4 and 10 mL of 5 (w/v) hydroxylamine hydrochloride, was determined. The detection limit, enhancement factor, and repeatability of the optimized method for Cr(III) were calculated to be 1.5 µg L-1, 38.5, and 1.78, respectively. The method was validated by the analysis of TMDW-500 drinking water and LGC7162 Strawberry Leaves as certified reference materials. The relative error for total chromium was found to be lower than 4.6. Recoveries were obtained quantitatively using this method (≥95).