A novel vortex assisted dispersive solid phase extraction of some trace elements in essential oils and fish oil

Abstract

In this paper, a novel vortex assisted solid phase extraction procedure combined with inductively coupled plasma optic emission spectrometry was presented for determination of Mn, Cu, Ni, Cr, Cd and Pb directly in oily matrix. The suggested separation and preconcentration method was based on simultaneous sorption of the target analytes from real essential oil matrix onto γ-Al2O3 functionalized with fluorescein (Al-Flr) and transfer to aqueous eluent prior to quantification. The effect of different parameters including sorption and elution time, sample volume, eluent type and concentration and interfering ions were investigated. The working conditions were given as follows, vortex agitation for sorption and elution 40 s, sample volume 20 mL, eluent type HCl, eluent concentration 0.3 mol L−1. The detection limits were found to be 0.7 μg L−1 for Mn, 4.1 μg L−1 for Cu, 1.0 μg L−1 for Ni, 1.6 μg L−1 for Cr, 0.7 μg L−1 Cd and 1.0 μg L−1 Pb. The evaluation of the accuracy and precision of the method was tested via metallo-organic certified reference material. The recovery values have warranted the accuracy and found between 98.4 and 103.3% with 2.6–6.4% relative standard deviation (RSD, %). The sampling frequency of the procedure was calculated as 11.25 h−1.Finally, the proposed analytical method was successfully applied on analyte spiked and unspiked apricot, black cumin, pine turpentine, thyme, mint essential oils and fish oil samples without any need of performing mineralization pretreatments.