INVESTIGATIONS ON THE CYANOGEN-BROMIDE ACTIVATION OF XANTHAN GUM

The CNBr activation procedure has been investigated as a means of synthesizing derivatives of xanthan gum. Both the titration and buffer methods of the procedure were compared. While the degrees of activation obtained from both methods were pH-dependent, the buffer method gave a slightly greater concentration of active groups. Imidocarbonates constituted the major reactive species in the activated polysaccharide. This indicated that the mechanism of activation and hence, coupling with amino-ligands, of CNBr-activated xanthan was similar to that postulated for Sephadex and other polyglucose polysaccharides. However, the degree of activation of xanthan gum was considerably reduced in comparison to values obtained with Sephadex activated in a similar manner.