Firstly, hydrolyze your polysaccharides,and then find a suitable derivative for monosaccharides, and detect  these monosaccharides by LC-MS.

Anal. Biochem. 418 (2011) 24–29

This paper maybe is useful for you.

Thank you for valuable reply can  done monosaccharides analysis without derivatation

Saccharides are difficult to analyze with LC-MS. If you don't want to derivatize you might use APCI and split in chlorphoporm (after separation) approximatly 5%. You will produce in this case chloride aducts which are easyer to detect. For sparation use a suitable HILIC coulumn, maybe based on this method http://www.imtaktusa.com/site_media/files/phase_brochures/Booklet_Unison_Amino_.pdf

I personally think that MALDI-ToF-MS is better suited to carbohydrate analysis.