Enrichment and flame atomic absorption spectrometric determination of palladium using chelating matrices designed by functionalizing Amberlite XAD-2/16 and silica gel

Six chelating matrices have been prepared by anchoring 2,3-dihydroxypyridine (DHP) and 2{[ 1-(3,4-dihydroxyphenyl) methylidene] amino} benzoic acid (DMABA) onto Amberlite XAD-2 and XAD-16 and 3,4-dihydroxybenzaldehyde (DHB), and iminodiacetic acid (IDA) onto silica gel. The materials were explored for enrichment of palladium followed by its determination with flame AAS. The optimum pH ranges for quantitative solid phase extraction by these matrices are from 4.0 - 5.5 to 5.5 - 7.0. The flow rates ( column procedure) and concentration of HCl required for desorption have been optimized. Thiourea ( similar to 3%) is essential for quantitative recovery of Pd. The t(1/2) values are between 5 and 15 min. The sorption capacity varies from 38 to 192 mu mol g(-1) ( highest for silica gel loaded with iminodiacetic acid). The preconcentration factors were found in the range 20 - 150. Tolerance limits of foreign species in the enrichment are reported. The enrichment procedures coupled with FAAS determinations were applied to synthetic solutions corresponding to standards GBW07293 and NIST SRM 2557 successfully.