Sorption processes of noble metals on silica gel surface with covalently grafted N-(5-mercapto-1,3,4-thiadiazol-2-yl)-N'-propylurea groups (MTS) were studied. It was found that sorption onto MTS may occur via complexation and/or anion-exchange mechanisms depending on the acidity of the solutions. It was shown that differences in the kinetics and temperature conditions for the sorption of platinum and gold can be used to separate micro-amounts of these metals in solution.