Determination of Copper Using Supramolecular Solvent-based Microextraction for Food, Spices, and Water Samples Prior to Analysis by Flame Atomic Absorption Spectrometry

A simple and sensitive supramolecular solvent microextraction method was developed for the separation, preconcentration and determination of trace levels of copper in food and environmental samples. The supramolecular solvent system consists of tetrahydrofuran (THF) and undecanol and was used as an extraction solvent for the microextraction procedure of Cu(II). A supramolecular solvent microextraction procedure for copper(II) as its 5-methyl-4-(2-thiazolylazo) resorcinol (5-ME-TAR) complex was established prior to micro-sampling flame atomic absorption spectrometric determination. The influence of various analytical parameters including pH, solvent type and volume, amount of 5-methyl-4-(2-thiazolylazo) resorcinol, and centrifugation time were investigated. The effects of certain alkali, alkaline earth, and transition metal ions on the quantitative extraction of copper(II) were also studied. The proposed supramolecular solvent-based microextraction procedure exhibits a limit of detection (LOD) of 1.4 mu g L-1 and a limit of quantification (LOQ) of 4.6 mu g L-1. A preconcentration factor of 60 was obtained and the relative standard deviation was 2.78%. The method was validated by the analysis of certified reference materials and applied to food, spices, and water samples