A simple and rapid dispersive liquid-liquid microextraction based on solidification of floating organic drop method combined with flame atomic absorption spectrometry for preconcentration and determination of copper.

A simple and rapid dispersive liquid-liquid microextraction based on solidification of floating organic drop method prior to flame atomic absorption spectrometry was developed for preconcentration and determination of copper. In this technique, simultaneous complex formation and extraction was performed with rapid injection of a mixture containing ethanol, 1-undecanol, and 1-(2-pyridylazo)-2-naphthol into a water sample spiked with Cu(II). After centrifugation, the test tube was cooled in an ice bath, and solidified extract transferred into a conical vial. Finally, it was dissolved into ethanol and copper concentration was determined. Some effective parameters of extraction and complex formation, such as extraction and disperser solvent type and volume, pH, concentration of the chelating agent, salt effect, and extraction time, were optimized. Under the optimum conditions, the calibration graph was linear in the range of 0.50 ng/mL to 0.30 microg/mL, with an LOD of 0.16 ng/mL. The RSD for 10 replicate measurements of 50.0 ng/mL of copper was +/- 1.4%. Two certified reference materials were analyzed, and the determined values were in good agreement with the certified values.