A new extractant-impregnated resin, alizarin red S -impregnated XAD-2010, is used as an adsorbent to separate and preconcentrate U(VI) and Th(IV) ions prior to their spectrophotometric determination. Various instrumental techniques such as elemental analysis, FTIR, and SEM analysis were employed for full characterization of the synthetic extractant. Optimization of the adsorption and elution conditions of U(VI) and Th(IV) ions using synthesized alizarin red S -impregnated XAD-2010 were studied. Langmuir isotherm model has the best fitting experimental data with a maximum adsorption capacity of 20.2 mg g −1 for U(VI) and 18.25 mg g −1 for Th(IV). The adsorption process of each metal ion by synthesized alizarin red S -impregnated XAD-2010 showed an exothermic pseudo-second-order adsorption process. The tolerance limits for several metal ions on alizarin red S -impregnated XAD-2010 were calculated, giving high tolerance limit. The optimized method was applied on international certified samples and different rock types bearing thorium and uranium with accurate results.

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A developed method was designed for gold determination directly in organic medium in some sedimentary rocks (fine sandstone, carbonates), pyrite, serpentine and international standard gold sample (MA-1a) using flame atomic absorption spectroscopy (FAAS). Instrumental parameters; burner angle, fuel flow rate, band pass and burner height together with chemical parameters; different media, leaching and interference effect were optimized to improve gold determination. Selective leaching using a new mixture (5% KCN, 5% Na2S2O3 and hydrogen peroxide) offered maximum leaching percentage of gold (>99%) with minimal concentration of accompanying elements. Extraction parameters using methyl isobutyl ketone (MIBK) from 3 M HCl were optimized for more than 99% gold extraction, followed by scrubbing using 0.1 M HCl. Gold was determined directly in organic phase. Beer's law was obeyed from 0.01 μg/ml to 10 μg/ml. Standard deviation (from 0.017 to 1.05) and percentage error (from 1.5% to 2.5%) using the present developed AAS method were calculated.

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