Adsorption Of Some Carbohydrates
ADSORPTION OF SOME CARBOHYDRATES
ON ULTRAFINE SILICA SURFACE
N. P. Galagan, T. V. Kulik, L. I. Dembnovetskaya
Institute for surface chemistry, National Academy of Sciences of Ukraine Prospekt Nauki 31, 252022 Kyiv, Ukraine
In present study results were obtained on adsorption of several carbohydrates by chemically modified silica surface. Two aminosugars were investigated (N-acetylglucosamine and galactosamine), of three monosugars (glucose, galactose and fructose), of disaccharide saccharose and tri-saccharide raffinose on ultrafine pyrogenic silicas with grafted hydroxi- and aminogroups. Physico-chemical characteristics of adsorption observed in experiments appeared to be in good agreement with adsorption properties derived from adsorption isotherms and desorption curves of examined compounds.
The method of temperature-programmed desorption of monosugars with mass spectrometric registration of volatile products was found to be most promising in studies of biomolecules on the ultrafine silica surface.
It was proved that amino, di- and tri-sugars were efficiently adsorbed by hydroxilated silica surface whereas monosugars weren’t. Adsorption of both mono and oligosaccharides was observed on aminated silica surface. This fact confirmed the assumption that presence of aminogroup promotes adsorption of mono-sugars.
It was suggested that ion-ion interaction took place on hydroxilated surface caused by OH groups of di- and tri-sugar molecules. On the aminated surface of silica, formation of hydrogen bonds may be expected involving surface aminogroups and alcohol groups of carbohydrate, in addition to mention ion-ion interactions.
Characteristics of oligosacharide adsorption on ultrafine silica surface depends essentially not only upon presence of definite adsorption sites but also upon structural peculiarities of carbohydrate monomers participating in the process of adsorption.
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