Spectroscopic studies of glycine/alumina surfaces

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Australian Institute of Physics
The basic field of surface adsorption and complexation of amino-acids on various oxide surfaces is an interesting area of investigation that has direct relevance in such diverse fields as chemistry (geochemistry, biochemistry), biotechnology (medical implants, biosensors, tissue engineering, bioelectronics, biomimetics and artificial photosynthesis), radiation technology (radiation damage and detection), colloid chemistry, surface chemistry and physics. The combination of both photoemission and neutron spectroscopy is quite rare and yet extremely powerful as these techniques directly yield the electronic and vibrational structure of a material respectively: two of the most basic properties of materials. Photoemission spectroscopy is clearly surface sensitive and hence is an ideal probe to study surface chemistry. While neutron spectroscopy is the domain of vibrational spectroscopy on bulk materials. There are exceptions to this rule where the surface dominates the scattered signal due to huge surface to volume ratios and large scattering cross-sections from adsorbate molecules. This study aim to exploit such ideas. The deposition of glycine onto alumina from solution is investigated by both inelastic neutron spectroscopy and high resolution photoemission. Studies focused on the extent of adsorption at various pH's, the character of each adsorbate (zwitterionic, basic, acidic), and the number of discrete surface sites of adsorption. Results show strong chemisorption of glycine through an ester type bond with the alumina surface across arrange of pH. Direct sorption of the amine group with alumina is observed only at pH9. Formation of multilayers and/or peptides is postulated to also occur which may have implications in the area of prebiotic chemistry.
Aluminium compounds, Amino acids, Chalcogenides, Energy levels, Organic compounds, Oxides, Oxygen compounds, Scattering, Sorption, Spectroscopy
Stampfl, A. P. J., & Pereira, J. E. M. (2017). Spectroscopic studies of glycine/alumina surfaces. Poster presented to the 41st Annual Condensed Matter and Materials Meeting, Charles Sturt University, Wagga Wagga, NSW, Australia, 31st January - 3rd February 2017, (pp. 105). Retrieved from: https://physics.org.au/wp-content/uploads/cmm/2017/Wagga_2017_Conference_Handbook.pdf