Dipeptide-functionalized mesoporous silica spheres

The preparation of surfactant-templated mesoporous silica spheres functionalized with carnosine moieties (dipeptide beta-alanyl-L-histidine) is described. The procedure involves the hydrolysis and co-condensation of a carnosine-containing organotriethoxysilane and tetraethoxysilane (TEOS) in water/ethanol solution in the presence of ammonia acting as catalyst and cetyltrimethylammonium bromide (CTAB) as templating agent. The resulting organic-inorganic hybrid displays spherical shape as evidenced by electron microscopy and narrow particle size distribution. It exhibits high specific surface area (775 m(2) g(-1)), as determined from the N-2 adsorption isotherm, and the XRD pattern is characteristic of a mesostructure with wormholelike framework. Functionalization was confirmed by IR spectroscopy and solid-state Si-29 and C-13 MAS NMR. The regular mesoporous structure can be advantageously exploited in processes where diffusion is the rate-determining step, as exemplified for the electrochemical detection of trace copper(II) after preconcentration at a carbon paste electrode modified with the material. (C) 2003 Published by Elsevier B.V.