Chemically Modified (Nano)Silica as Sensitive Material for Arginine and Lysine

Silica has been derivatized with aminopropyl groups which subsequently have been chemically modified with N -methoxy-2,6-dinitroaniline derivatives to yield a solid which changes its color in the presence of arginine or lysine, from yellow to blue. Other amino-acids (such as glycine, valine, cysteine, cystine, alanine, phenylalanine, histidine) do not showed this behavior. The same procedure may be applied to silica nanoparticles. The new materials were characterized by UV–Vis, IR, and TEM. Graphical Abstract Visible spectra of a water solution of derivatives silica nanoparticles in absence (dash line) and in the presence of arginine or lysine (solid line).