Determination of Au(III) and Pd(II) ions by FAAS after their preconcentration on [6-(thiophen-2-yl)pyridin-2-yl]methylamine bonded silica gel

In this thesis, a novel adsorbent was prepared by covalently attachment of [6-(thiophen-2-yl)pyridin-2-yl]methylamine to silica gel surface. The synthesized modified silica gel was characterized by elemental analysis and FTIR spectroscopy. The concentrations of Au(III) and Pd(II) ions were determined by flame atomic absorption spectrometry after their simultaneous column solid phase extraction using this adsorbent. In the column solid phase extraction studies, the parameters such as sample pH, sample volume, sample flow rate, type of eluent, eluent volume, matrix ions were optimized. The optimum conditions were found as the sample solution pH, 1.0; eluent, 3.0% thiourea in 1.0 M HCl; eluent flow rate, 2.5 mL/min and sample flow rate, 7.5 mL/min. The preconcentration factor was found to be 50 for Au(III) Pd(II) ions. Using a preconcentration factor of 50, the detection limits (3ϭ) for Au(III) Pd(II) was calculated to be 0.38 and 1.04 µg/L using the proposed method, respectively. By the determination Au(III and Pd(II) ions spiked to be 0.4 mg/L in deionized water samples using the proposed method, RSD, % and recovery, % for Au(III) Pd(II) ions were found to be 2.0 and 1.9, and 97 and 98, respectively. Experimental adsorption capacity of [6-(thiophen-2-yl)pyridin-2-yl]methylamine bonded silica gel from solution containing 0.1 and 1.0 M HCl was found to be 52.1 and 14.5 mg/g for Au(III) ions, and 51.2 and 22.4 mg/g for Pd(II) ions, respectively. It was revealed that the concentrations of Au(III) and Pd(II) ions at trace levels in various water samples can be successfully determined using the proposed method