structural information on the major oligosaccharides was obtained from ( a ) their susceptibilities to endo-beta-galactosidase before and after desulphation , ( b ) their elution positions on a column of bio-gel p-4 and retention times on a high-performance anion-exchange column and ( c ) negative-ion fast-atom-bombardment mass spectrometry .
C0003075
anion
C0022023
ion