Optimization of dispersive liquid-liquid microextraction for the selective determination of trace amounts of palladium by flame atomic absorption spectroscopy

A new simple and reliable method for rapid and selective extraction and determination of the trace levels of Pd2+ ion was developed by dispersive liquid-liquid microextraction preconcentration and flame atomic absorption spectrometry detection. In the proposed approach, thioridazine HCl (TRH) was used as a Pd2+ ion selective complexing agent. The effective parameters on the extraction recovery were studied and optimized utilizing two decent optimization methods: factorial design and central composite design (CCD). Through factorial design the best efficiency of extraction acquired using ethanol and chloroform as dispersive and extraction solvents respectively. CCD optimization resulted in 1.50mL of dispersive solvent; 0.15mL of extraction solvent; 0.45mg of TRH and 250mg of potassium chloride salt per 5mL of sample solution. Under the optimum conditions the calibration graph was linear over the range 100-2000 mu gL(-1). The average relative standard deviation was 0.7% for five repeated determinations. The limit of detection was 90 mu gL(-1) L-1. The average enrichment factor and recovery reached 45.7% and 74.2% respectively. The method was successfully applied to the determination of trace amounts of palladium in the real water samples. (C) 2009 Elsevier B.V. All rights reserved.