Designing a simple semi-automated system for preconcentration and determination of nickel in some food samples using dispersive liquid–liquid microextraction based upon orange peel oil as extraction solvent

A simple semi-automated dispersive liquid–liquid microextraction system was designed and used for off-line preconcentration and determination of nickel (II) ion in some food samples. The methodology submitted in the present work is based upon the microextraction of [Ni(C38H28O2N)2] complex employing an orange peel oil (OPO) as an extractant without a dispersing solvent and the estimation of nickel (II) ion in sediment by electrothermal atomic absorption spectrometry (ETAAS). 3 mL of sample solution, 0.5 mL of acetate buffer (pH 6), and 300 µL of the complexing agent (1-[4-[(2-hydroxynaphthalen-1-yl)methylideneamino] phenyl]ethanone) (HNE) dissolved in OPO were automatically transferred to separation tube and the cloudy solution was obtained by dispersing OPO as droplets throughout the aqueous phase using nitrogen gas. Under the optimized conditions, the analytical methodology used in this study provided a good efficiency in term of sensitivity and selectivity where the calibration plot was linear in the range of 5–150 ngL–1, while, the enhancement factor (EF) and the detection limit were 300 and 0.87 ngL–1, respectively for a sample volume of 3 mL. On the other hand, the method was completely free of most potential interferences. Certified reference wheat sample (NCS ZC11018) and some food samples were used to evaluate the developed method and results were compared using ICP–MS. Moreover, the new [Ni(C38H28O2N)2] complex was synthesized and characterized using diverse characterization techniques.