Dipeptide-functionalized mesoporous silica spheres

The preparation of surfactant-templated mesoporous silica spheres functionalized with carnosine moieties (dipeptide β-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 m2 g−1), as determined from the N2 adsorption isotherm, and the XRD pattern is characteristic of a mesostructure with wormholelike framework. Functionalization was confirmed by IR spectroscopy and solid-state 29Si and 13C 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.