Extraction and determination of trace amounts of palladium by narrow-bore tube dispersive liquid-liquid microextraction method and UV/Vis spectrophotometry

In this research, a simple, rapid and effective microextraction technique, named “narrow-bore tube dispersive liquid-liquid microextraction” is introduced for the extraction and preconcentration of palladium from aqueous samples, followed by its UV/Vis spectrophotometric determination. To perform extraction, a solution of palladium and cetylpridinium chloride surfactant was poured into a glass narrow-bore tube. p-dimethyl aminobenzilidene rhodanine (PDR), heptanol and ethanol were used as the complexing agent, extraction solvent and dispersing solvent, respectively. The effective parameters affecting micro-extraction efficiency; including type and volume of extraction and dispersing solvents, pH of the sample solution, concentration of surfactant and ligand, sample volume and injection time were investigated and optimized. Under the optimized conditions, the calibration curve was linear in the range of 40-1300 µg mL-1 for Pd and reproducibility (as relative standard deviation) was better than 5.5%. Limit of detection of the method was calculated to be 6.4 µg mL-1 with an enrichment factor of 37.5. The method was applied successfully for the extraction and determination of palladium in two mineral and tap water samples.