Characterization of Cellooligosaccharides Using NMR Spectroscopy and X-ray Photoelectron Spectra

1H-1H COSY and 13C-1H HSQC spectra were used to assign cellotriose, cellotetraose and cellopentaose preparatively separated on Bio-Gel P-2 column (2.5cm×125cm). The results illustrate that the configuration ratios of α-form to β-form (α/β) at C1 of the reducing end decrease with the increase of degree of polymerization (DP) for cellooligosaccharides in aqueous solution. The configuration for cellotriose is mainly the α-form (α/β, 0.52), while for cellotetraose and cellopentaose are mainly the β-form (α/β, 0.34 and 0.25 respectively). X-ray photoelectron spectra (XPS) analysis shows that the binding energy of C 1s was mainly assigned to 284.8 and 286.1 eV corresponding to C 1s1 (C—O) and C 1s2 (O—C—O), respectively. The ratios of C 1s1/C 1s2 increase with the increase of DP for cellooligosaccharides.