Platinum metals-solution chemistry and separation methods (ion-exchange and solvent extraction).

Photoinitiated gold sol generation in aqueous Triton X-100 and its analytical application for spectrophotometric determination of gold.

A 2-mercaptobenzothiazole-bonded silica gel chelating adsorbent(MBTSG) was synthesised by the Mannich reaction between 2-mercaptobenzothiazole and aminopropyl silica gel, and its adsorption characteristics were studied in detail. AuIII, PtIV and PdII can be quantitatively adsorbed by the adsorbent from aqueous solution at pH≤5.0 and CH+≤6 M. The adsorption capacities of AuIII, PtIV and PdII were >4.5, >6.5 and >18 mg per gram of dry MBTSG, respectively. The adsorbed metal ions can be readily desorbed with 3% thiourea in 3 M HCl solution. Other metal ions caused little interference in the preconcentration and simultaneous determination of AuIII, PtIV and PdII by ICP-OES. Concentrations of 2 ppb of Au, Pt and Pd can be determined reliably with a preconcentration factor of 250.

2-Mercaptobenzothiazole-bonded silica gel as selective adsorbent for preconcentration of gold, platinum and palladium prior to their simultaneous inductively coupled plasma optical emission spectrometric determination

New approaches for acceleration of cloud point extraction of Rh, Pd and Pt by microwave and ultrasound irradiation have been investigated. 2-Mercaptobenzothiazole and Triton X-100 were used as ligand and non-ionic surfactant, respectively. Microwave irradiation substantially increased the procedure efficiency. In contrast no significant effect was observed when a micellar solution was treated with ultrasound energy. The acceleration of complex formation reactions by reducing agents (KI and SnCl2) has also been studied. The use of SnCl2 was a prerequisite for quantitative extraction of Rh. Since the extraction kinetics of platinum depends on its oxidation state and presence of Pd, the addition of SnCl2 equalized the platinum extraction behavior. For the first time the whole cloud point procedure was successively accomplished in a microwave system. 10 min of irradiation were sufficient for gravimetrical phase separation and quantitative extraction of platinum group metals. As a result the procedure time was shortened by a factor of 9 in comparison to conventional hot plate cloud point extraction. The surfactant-rich phase was analyzed after dilution with 1 M HCl by continuous nebulization to ICP-MS. Quantitative recoveries and good plasma tolerance were reported. Detection limits of 1 ng.l−1 (Rh), 5 ng.l−1 (Pd), and 6 ng.l−1 (Pt) were achieved regarding a preconcentration factor of 8. The microwave-assisted cloud point extraction has been successfully applied for simultaneous determination of trace amounts of platinum group metals in pharmaceutical products (Tritace, Vivace, Laprilen and Enalapril).

Microwave-assisted cloud point extraction of Rh, Pd and Pt with 2-mercaptobenzothiazole as preconcentration procedure prior to ICP-MS analysis of pharmaceutical products

Studies on the extraction of platinum metals with tri-iso-octylamine from hydrochloric and hydrobromic acid: separation and determination of gold, palladium and platinum.

A. Diamantatos

Papers

The solvent extraction of platinum-group metals and gold with 2-mercaptobenzo-thiazole