Use of chelating resin YPA4 micro-columns for the on-line preconcentration and separation of gold(III), silver(I), palladium(II) and platinum(IV) in geological and environmental samples and their determination by inductively coupled plasma-atomic emission spectrometry

A simple and selective method of flow injection (FI) using a micro-column packed with chelating resin YPA(4) as solid phase extractant was developed for the preconcentration and separation of trace amount of noble metals, Au(III), Ag(I), Pd(II) and Pt(IV), followed by ICP-AES determination. In HNO3 media, the chelating resin was selective towards Au(III), Ag(I), Pd(II) and PKIA and the analysed ions were readily desorbed quantitatively with 5 ml of 2.5% m/v thiourea. Effects of acidity, sample flow rate and concentration, elution solution and interfering ions on the recovery of the analytes were systematically investigated. Under optimum conditions, the adsorption capacities of YPA4 for Au(III), Ag(I), Pd(II) and Pt(IV) were 67.2, 43.1, 64.8 and 27.6 mg per gram of resin in HNO3 media, respectively. It was found that YPA(4) could be used for more than eight runs in HNO3 media without loss of capacity. The proposed method was used for the determination of trace noble metals in geological and environmental samples, and the analytical results obtained were in good agreement with the recommended values.