Compounds
15 (each 1 mg) were treated with 4 M trifluoroacetic acid (TFA) at
110 C for 4 h to give an acid hydrolysate. The acid hydrolysate was then
vacuum evaporated to remove the residual TFA. Subsequently, the
hydrolysate was mixed with 2 mL of 16 mM NaOH, and this solution
was used for DIONEX ICS 3000 high-pH anion exchange chromatography
pulsed amperometric detection (HPAEC-PAD, Sunyvale, CA,
USA).9 HPAEC-PAD analysis was performed on a Carbo Pac PA10
column(2 i.d.250mm) using 16mMNaOHas the eluent at a flowrate
of 0.25 mL/min. Two authenticmonosaccharides includingmannitol and
mannopyranose were used as standards. When compared with the
standards, the monosaccharide in 1 and 2 was confirmed to be mannitol,
while the monosaccharides in 35 were determined to be mannitol and
mannopyranose. Under the above conditions, the retention times of the
mannitol and mannopyranose were 3.25 and 12.80 min, respectively.