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

Abstract

In this research, a magnetic solid phase extraction based on the use of magnetic polyanilinepolythiophene 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%).

Chromium speciation in water using magnetic polyaniline nanoparticles coupled with microsampling injection-flame atomic absorption spectroscopy

“…The analytical performance Figures achieved in this study, as well as those reported in several recent studies on chromium speciation analysis [ 23 , 35 , 60 – 63 ], are compared in Table 6 . It could be concluded that the procedure exhibits fairly comparable characteristics across various parameters, including capacity, sorbent amount, preconcentration factor, LOD, and RSD when compared with other reported procedures based on the use of sorbent rich in imine, amine, or nitrogen groups.…”

“…However, because of the probable aggregation and oxidation of Fe 3 O 4 in an aqueous solution, nanoparticles are coated with various substances to develop feasible and effective preconcentration and speciation methods. Among these substances, conductive polymers containing highly delocalized π system with nitrogen, oxygen, and/or sulfur groups that can complex with metal cations are more appropriate options for metal speciation analysis without the need for complexing agents [ 22 , 23 ]. These polymers can constitute different sorption mechanisms, including complexation, ion exchange process, acid-base, and π-π interaction [ 24 ].…”