CHEMICAL COMPOSITION STUDY OF VANADIUM PENTOXIDE XEROGELS DOPED BY BOVINE ALBUMIN.

Metal-bioorganic compounds of vanadium pentoxide and bovine serum albumin (BSA) (Fraction V) were obtained by using sol-gel method. Series of the samples (BSA) _xV₂OH₂O, where , 0.01 and 0.001, were originally produced by the synthesis of vanadium pentoxide xerogels and subsequent blending with water-dissolved BSA in appropriate molar ratios. It was evident that the gelation process does not occur for . For the X-ray photoelectron spectroscopy (XPS) studies, the thin layers of these materials were prepared by drying the gel onto the glass and mica substrates. The surface morphology of the samples was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. It follows from the analysis of experimental XPS spectra of (BSA) _xV₂OH₂O that the nitrogen ions in pure albumin and in (BSA)V₂OH₂O are present in imine, amine and protonated amine groups. The additional protonated amine arises when the concentration of albumin in (BSA) _xV₂OH₂O is low (). Increasing the amount of albumin results in decrease of the number of oxygen ions bonded to vanadium. At the same time (with increase of albumin), the component of oxygen bounded to carbon and nitrogen is increasing. In the samples with greater amount of albumin, the reduction of vanadium ions occurs. This means that the trivalent and tetravalent vanadium ions are present together with pentavalent ones. [ABSTRACT FROM AUTHOR]