Separation and preconcentration of gold and palladium ions with a carboxylated pillar[5]arene derived sorbent prior to their determination by flow injection FAAS

We report on the use of a water-insoluble pillar[5] arene derivative carrying ten carboxy groups as an adsorbent, packed in a glass microcolumn, for the separation and preconcentration of trace gold (Au) and palladium (Pd). Sample pH, sample loading time, sample flow rate, eluent concentration, and eluent flow rate were optimized. Effects of potentially interfering metal ions that are commonly encountered in soil were also investigated. Under the optimized conditions, the enrichment factors for Au and Pd are 12 and 16, respectively. Flow injection in combination with flame atomic absorption spectrometry was then applied for the quantitation of the elements. The analytical range is linear in the range between 0.05 and 1 mu g mL(-1) for both Au and Pd. The limits of detection are 15.9 mu g L-1 for Au and 16.0 mu g L-1 for Pd, with relative standard deviations (for n=11) of 0.7 % (Au) and 0.4%(Pd), respectively. The accuracy of the method was validated using certified reference materials (coal and ash) and geological samples.