Use of Silica Gel Chemically Modified with Mercapto Groups for the Extraction, Preconcentration, and Spectroscopic Determination of Palladium

Silica gel chemically modified with mercaptopropyl groups is proposed for the extraction and preconcentration of palladium. This silica gel extracts palladium(II) at an acidity from 6M HCl to pH 4 with distribution ratios at a level of n× 10⁴ g/cm³. Hyphenated procedures for the adsorption–photometric determination of palladium with detection limits of 0.1 g/0.1 g of the adsorbent have been developed. The procedure includes the adsorption preconcentration of palladium, elution by hot (50 ± 5°C) 8% thiourea in 1M HCl, and atomic absorption determination of palladium in the eluate (detection limit is 0.05 g/mL). The procedures were applied to the determination of palladium in standard reference samples of copper–nickel ore and copper concentrate.