A magnetic solid-phase extraction method using Fe3O4@coPANI-PTH for microsample injection system-flame atomic absorption spectrometric determination of nickel and copper in soft drinks and spice samples

Abstract

A magnetic solid-phase extraction using magnetite coated with polyaniline-polythiophene copolymer (Fe3O4@coPANI-PTH) was applied for preconcentration of Ni(II) and Cu(II) in some soft drinks and spice samples followed by microsample injection system-flame atomic absorption spectrometry (MIS-FAAS). Preconcentration optimisations including pH, amount of adsorbent, eluent type and volume, sample volume, interfering ion effects were investigated. Relative recoveries of 85.2–96.8% were satisfactorily obtained by extracting both analytes from 50 mL sample solution buffered at pH 10 to 0.5 mL eluent using 100 mg Fe3O4@coPANI-PTH. Good linearity was obtained ranging from 5 to 80 µg L−1 with a regression coefficient of 0.999. Limits of detection for Ni(II) and Cu(II) were 2.8 and 1.2 µg L−1, respectively. The accuracy of the method was confirmed by the analysis of certified reference samples and real samples spiked with the analytes. The relative error and standard deviation of the current method for both analytes were smaller than 6%. The established method was applied to commercially available some local soft drinks and spice samples. © 2020 Informa UK Limited, trading as Taylor & Francis Group.