An Insightful Approach to Understanding the Mechanism of Amino Acid Adsorption on Inorganic Surfaces: Glycine on Silica

Abstract

The adsorption of glycine on amorphous silica surface has been studied to demonstrate the catalytic activity of silica surfaces towards the formation of peptide bonds on prebiotic earth. Silica nanoparticles were synthesized using a microwave assisted method and the nanoparticles were characterized using SEM. Glycine was adsorbed from aqueous solution on the nanoparticles and the adsorption behavior was characterized using FTIR and TGA analyses. At a glycine concentration of 0.5M and at pH=7, favorable adsorption was observed which obeyed the Langmuir isotherm model. From the FTIR characterization, peptide bond formation was confirmed. It was concluded that the adsorption of glycine occurs via electrostatic interactions as well as hydrogen bonding between the silica surface and glycine molecules.