The use of 3- aminopropyltriethoxy silane (APS) as inorganic precursor in the synthesis of hybrid materials in substitution of traditional alkoxides such as tetraethylorthosilicate (TEOS), opens up the possibility of incorporate reactive amine groups into the three-dimensional network. These groups can be used in order to link different organic compounds to the material. On the other hand, the short times of APS hydrolysis, allow to work under very soft conditions, such us non acid media and room temperature, hence avoiding the decomposition of the organic active compounds. The aim of this work is the synthesis and characterization of nanocomposites in which traditional alkoxides are replace by APS. Primary amine groups incorporated into the inorganic network and present on the material surface are determined by reaction with specific chromophores.