The desalted oligosaccharide mixture was subjected to size exclusion chromatography (SEC)
using a Superdex Peptide column (GE Healthcare, USA) eluted at a flow rate of 0.5 mL/min with 25% (v/v) acetonitrile containing 50 mM ammonium formate. Parameters for the MS were as follows: gas temperature 350 °C; gas flow, 11 L/min; nebuliser pressure, 50 psi; capillary voltage, 4000 V; fragmentor voltage, 135 V; scanned mass, 100–2000 Da. The data acquisition for MS signals was made using Chemstation software (B.04.00 [B4038],