SEPARATION OF PALLADIUM(II) FROM PLATINUM(II), IRIDIUM(III), AND RHODIUM(III) USING CENTRIFUGAL PARTITION CHROMATOGRAPHY

The separation of Pd(II) from Pt(II), Ir(III) and Rh(III) with trioctylphosphine oxide (TOPO) in heptane using centrifugal partition chromatography (CPC) has been investigated for the first time. The extraction of Pd(II) has been studied by CPC and batch solvent extraction. The distribution ratios for Pd(II) determined by both methods agree well. In low HCl concentrations (<0.1 M), the extracted species was PdCl₂.(TOPO)₂, irrespective of the chloride concentration, while at acid concentrations above 0.1 M, the Pd was extracted as the ion pair, 2(TOPO.H⁺).PdCl₄ ^2-. Base line separation of Pd(II) and Pt(II) in CPC was obtained under a variety of chloride and HCl concentration with the average number of theoretical plates being 390 ± 40 at a flow rate of 0.47 ± 0.05 mL/min.