Determination of copper(II) by flame atomic absorption spectrometry after its perconcentration by a highly selective and environmentally friendly dispersive liquid–liquid microextraction technique

A new, simple, rapid, selective, and environmentally friendly method is proposed for the determination of Cu(II) ions based on the formation of the complex between these ions and salophen as the ligand followed by the dispersive liquid–liquid microextraction of the neutral hydrophobic complex formed in the organic phase and flame atomic absorption spectrophotometric detection. Various factors including the pH of the sample solution, concentration of salophen as the complexing reagent, type and volume of the extraction and disperser solvents, and extraction time affecting the extraction efficiency of Cu(II) ions and its subsequent analytical signal were studied and optimized. Under the optimized experimental conditions, the detection limit (3σ) and the enrichment factor were obtained to be 0.60 μg L−1 and 49, respectively, for 10.0 mL of the sample solution. The consumptive index was 0.20 mL and the calibration graph was linear in the range of 3.0–120 μg L−1. The relative standard deviations for six replicate measurements of 5.0, 20.0, and 50.0 μg L−1 of Cu(II) ions were 4.1%, 1.5%, and 1.8%, respectively. The proposed method was also successfully applied for the extraction and determination of Cu(II) ions in different water and food samples with satisfactory results.