Aqueous two-phase extraction of Au(III) and Pd(II)

An aqueous two-phase system, prepared by mixing a tetrabutylammonium. bromide (TBAB) solution and Na2SO4, was proposed for the extraction of Au(III) and Pd(II) prior to atomic absorption spectrophotometric(AAS) determination. An aqueous two-phase system was obtained as follows: to a 1 ml sample solution containing Au (III) and Pd(II), 3.0 ml of 1.0 mol l(-1) TBAB aqueous solution and 1.0 ml of a buffer solution (pH 4) were added and diluted with water to 6.0 ml. Then, 1.8 g of Na2SO4 was added to this solution and the mixture was shaken for about 1 min. After complete phase separation was performed, a 0.5 ml aliquot was taken from the upper phase and then diluted with 10 ml of water for AAS determinations of Au(III) and Pd(II). The Au(II) and Pd(II) were quantitatively extracted into the upper phase in the pH range from 1 to 6.5. The proposed method was applied for the determination of Au(III) and Pd(II) in a plating solution. The mean recoveries were 104 and 99% for Au(III) and Pd(II), respectively.