Application of Response Surface Methodology for Optimization of Conditions for Nickel Determination in Water and Vegetables by Switchable Solvent based Liquid Phase Microextraction

Abstract

A novel switchable-hydrophilicity solvent based liquid phase microextraction coupled with flame atomic absorption spectrometry has been applied for preconcentration and determination of Ni(II). Triethylamine (TEA) was selected as an inexpensive switchable solvent in the present work. Ni(II)-1-(2-pyridylazo)-2-naphthol complex was extracted into the TEA phase by converting the protonated carbonate to TEA. The experimental conditions were optimized using Plackett–Burman and Box–Behnken design methods. Such analytical parameters as the limit of detection, relative standard deviation and enhancement factor were 3 μg/L, 1.1% and 70, respectively. The calibration graph was linear over the range of 10 to 800 μg/L with the correlation coefficient of 0.998. The proposed method was successfully applied to the quantification of trace nickel in water and vegetable samples.