RESUMO
Objective To investigate the relative molecular weight of polysaccharides in Bletilla striata by matrix-assisted laser desorption ionizatior/time-of-flight mass (MALDI-TOF-MS). Methods 2, 5-Dihydroxybenzoic acid (DHB) as a matrix was used. By drop drying at room temperature the proportion of the matrix and polysaccharide sample was 1.5∶1. Baseline mode and laser intensity at 1 500-2 500 units were carried out. Results The relative molecular weights of polysaccharides in B. striata were 6?104-3?105, whose distribution rang was wide. Conclusion The relative molecular weights of polysaccharides in B. striata are obtained by MALDI-TOF-MS technique in the proportion of DHB-polysaccharides in B. striata 1.5∶1, which is valuable for the preparation and good quality by the direct drop drying method.
