Immobilised Pd (II) on a phosphine sulphide derivated polystyrene as affinity chromatographic material for the selective adsorption of amino acids

Two insoluble extractant systems based on a derivated polystyrene have been prepared for the separation and recovery of Pd (II). Those functional poly mers have been obtained by the incorporation of a phosphine sulphide on the Amberlite XE-305 chloromethylated polymer (macroporous polystyrene cross-l inked with 4% of DVB, containing 4 mmol Cl/g). This incorporation has been made by either direct attachment to the polymer or through a tris-ethoxylat ed chain as spacer between the polymeric backbone and the phosphine sulphid e unit to provide enhanced hydrophilic properties and to minimise the steri c hindrance for the phosphine sulphide moiety. Adsorption of Pd (II) from chloride solutions have been studied for the dif ferent polymers prepared and by varying the composition of the metal soluti on solvent by using mixtures of aqueous-dioxane media. The results obtained include the determinations of polymer capacity for Pd (II), the rate of metal adsorption and the polymer-Pd (II) capacity to take up tryptophan or tyrosine in a buffered media at pH = 6.5. The increase of dioxane concentration in the mixed media provides an increase of the capac ity and a faster kinetics for Pd (II) adsorption, in both polymers. The determination of capacity factors for the adsorption of amino acids (tr yptophan and tyrosine) has been carried out under a variety of conditions. The observed differences on these parameters are a clear indication of the selectivity of the adsorption process. (C) 1999 Elsevier Science BN. All ri ghts reserved.