COLUMN SOLID PHASE EXTRACTION OF GOLD, PALLADIUM AND COPPER AT TRACE LEVELS ON MODIFIED SILICA GEL FOR THEIR ATOMIC ABSORPTION SPECTROMETRIC DETERMINATION

摘要

A method for the preconcentration of Au (Ⅲ), Pd (Ⅱ) and Cu (Ⅱ) is proposed using a minicolumn filled with silica gel modified by 3-[2-(2-aminoethylamino)ethyl-amino]propyl group (AEAEAP-SG). The retained analytes on the modified silica gel were recovered with a small volume of KCN (potassium cyanide) solution. The metal ions in the eluent were determined by flame atomic absorption spectrometry (FAAS). Different factors, such as the pH of the sample solution, the sample volume, the flow rate of the sample solution, eluent volume, and matrix effects on preconcentration were examined. The recoveries for the analytes under optimum preconcentration conditions were higher than 99%. The limits of detection (δ) for Au (Ⅲ), Pd (Ⅱ) and Cu (Ⅱ) ions were found to be 0.037, 0.021 and 0.013 μg ml~(-1), respectively. Validation of the preconcentration technique described in this study was carried out against the certified reference material (SARM 7B) by determining gold and palladium content. The results showed good agreement with the certified values. Copper was determined in river and seawater. Au, Pd and Cu were determined with relative errors lower than 10%.