In my research work, I am to separate the monosaccharides, oligosaccharides, and polysaccharides in the traditional Chinese medicine mixture.Who could give me a suggestion?
Thanks!

You should first inspect a presumable composition of these Chinese mixes, i.e. whether oils, lipids, proteins or other amphophilic or lipophilic compounds are present. Such compounds can easily be removed by extraction. Both neutral and polar mono and oligosaccharide (up to 8 residues)then have to be analyzed on Carbohydrate Analysis type column from Waters using simple 70/30 acetonitrile/water mobile phase with a UV detection at 190-200 nm (you should use a high-quality acetonitrle). Smaller molecules eluted first. Based on my experience, this separation is unable to characterize trace amounts but allows to perform online MS. Further, try to analyze carbohydrates on ion-exchange resin in Ca-, H-form(Sugar Pak from Waters, for example) using heated water (60-80 Celcium degree) with RI detection. The method is very sensitive, but is not suitable for polar carbohydrates. Larger molecules eluted first. Avoid any alcohols in analyte - they are very well retained and therefore can interfer with your compounds. Polysaccharides are to be analysed on SEC column.
Good luck