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

Abstract

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. Au^III, Pt^IV and Pd^II can be quantitatively adsorbed by the adsorbent from aqueous solution at pH≤5.0 and C_H⁺≤6 M. The adsorption capacities of Au^III, Pt^IV and Pd^II 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 Au^III, Pt^IV and Pd^II by ICP-OES. Concentrations of 2 ppb of Au, Pt and Pd can be determined reliably with a preconcentration factor of 250.