SORPTION AND PRECONCENTRATION OF METAL-IONS ON SILICA-GEL MODIFIED WITH 2,5-DIMERCAPTO-1,3,4-THIADIAZOLE

Silica gel, chemically modified with 2,5-dimercapto-1,3,4-thiadiazole [=Si(CH2)(3)-NC2HNS3], abbreviated as SiB, was used to adsorb metal io ns from ethanol by both batch and column techniques. Elution of Cu(II) was done with a solvent mixture of acetone and hydrochloric acid (9:1 v/v). Zn(II), Cd(II), Ni(II), Pb(II), Co(II) and Fe(III) were eluted with 0.5 mol l(-1) HC1 in ethanol solution. The modified silica was ap plied in the preconcentration of metal ions from commercial ethanol, n ormally used as engine fuel. The method is suitable for quantifying th ese metals at low mu g l(-1) levels.