Determination of gold(III) and palladium(II) in mine samples by cloud point extraction preconcentration coupled with flame atomic absorption spectrometry

A simple, cheap, and nonpolluting method was developed for the cloud point extraction of gold (Au) and palladium (Pd). It is based on the complexation reaction of Au and Pd with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) and micelle mediated extraction of the complex using the non-ionic surfactant poly(ethylene glycol) mono-p-nonylphenyl ether (PONPE 7.5). Under the optimized experimental conditions, the enrichment factors are 16 and 17 for Au and Pd, respectively, for 15 mL of preconcentrated solution. The limits of detection are 3.8 mu g L-1 and 1.8 mu g L-1 for Au and Pd, respectively. The relative standard deviations are 1.4% for Au and 0.6% for Pd (n = 11). The method was successfully applied to the determination of Au and Pd in certified reference materials and mine samples.