Determination of trace amounts of copper in water samples by flame atomic absorption spectrometry after preconcentration on octadecyl-bonded silica membranes modified by a Di-Schiff base ligand

A simple method for rapid extraction-preconcentration and determination of trace amounts of copper(II) ions in water samples by using octadecyl-bonded silica membranes modified by a Schiff base, named bis(5-chloro-2-hydroxyacetophenone)-1,2-propanediimine (L), followed by flame atomic absorption spectrometry (FAAS) is described. The effect of parameters influencing the extraction efficiency, i.e. pH of the sample solution, amount of the modifier, type and volume of stripping reagent, and sample and stripping reagent flow rates were evaluated and optimized. The detection limit and the concentration factor of the presented method are 10.2 ng/L and greater than 400, respectively. Under optimum experimental conditions the capacity of the membrane disks modified by 4 mg of the ligand was found to be 142.8 (±0.2) μg of copper. The method was applied to the enrichment and determination of copper content in different natural water samples.