Role of surface adsorption and porosity features in the molecular recognition ability of imprinted sol–gels

Organically modified molecularly imprinted silicas (MIS) for nafcillin recognition were prepared using a simple sol–gel procedure. Molecular recognition of the template was observed by tuning the chemical and structural properties of the MIS. The relative amounts of organically modified alkoxysilane precursors were found to be key in the textural and morphological characteristics of the MIS as well as for developing an imprinting effect in the materials. The recognition properties of the imprinted materials were found to be strongly influenced by the hydrolytic stability of the alkoxysilanes and their inductive effects during sol–gel hydrolysis/condensation stages. The concept was to combine properties of organic groups with those of glass-like materials in order to develop synergetic properties through variations in the composition. Results from batch rebinding experiments as well as from the thorough study of the N2 adsorption properties and the textural and structural characteristics of the MIS revealed that an imprint effect could be attributed to the presence of the template during the synthesis of MIS.