FAAS Determination of Au and Pd After Selective Preconcentration on Ethylenediamine Silica Material Prepared By the Sol-Gel Method

In this study, a selective pre-concentration method for trace Au(III) and Pd(II) ions based on their sorption on modified silica material is presented. The modified silica with ethylenediamine was prepared using the sol-gel technique and is characterized by elemental analysis and FT-IR spectrometry. Au(III) and NOD ions were quantitatively retained on the column at slightly acidic conditions, loaded with modified silica, and then successfully eluted with a solution of thiourea 1% (m/v) in 0.1 M hydrochloric acid. The metal ions in the eluate were determined by flame atomic absorption spectrometry. The effects of different factors, such as pH of the sample solution, sample volume, flow rate of sample solution, type of eluent and matrix content of the sample solution on preconcentration, were examined to obtain optimum conditions. The recoveries for Au(111) and Pd(II) ions under optimum preconcentration conditions were 99 +/- 2 and 98 +/- 2% at the 95% confidence level, respectively. The analytical detection limits of Au and Pd were 0.20 and 0.21 mu g L-1, respectively. The presented method was validated by the analysis of certified reference platinum ore (SARM7B). The obtained results agreed with the certified values.