A modified GC-MS analytical procedure based on trimethylsilyl-dithioacetal (TMSD) derivatization has been established for a simultaneous determination of thirteen carbohydrates. Different from previous approaches, the current GC-MS method was featured by a powerful practicability for simultaneous detection of aldoses, uronic acids, ketoses, and amino sugars; simplifying GC-MS chromatograms and producing a single peak for each derivatized sugar, as well as high resolution, sensitivity, and repeatability. An additional liquid-liquid extraction from derivatization mixtures was performed not only to increase the detection sensitivity of amino sugars but also to decrease the by-products of derivatization. Contrarily, three amino sugars were detected at a very low intensity or not detected at all. The effect of time on monosaccharide- mercaptalated reaction was systematically investigated. The effect of trimethylsilylation on the formation of TMSD was also optimized. The established GC-MS based on TMSD derivatization was suitable for complex carbohydrate analysis and has been successfully applied for the detection of free carbohydrates in water extracts of Anemarrhena asphodeloides roots and determination of monosaccharides in Glossy ganoderma polysaccharides.

Ephedra sinica polysaccharides have been reported to possess important activities, so quality evaluation of polysaccharides from the genus Ephedra is urgent. In this study, enzymatic digestions were performed to establish multiple saccharide fingerprints by ultra-performance liquid chromatography with electrospray ionization triple quadrupole linear ion trap mass spectrometry (UPLC-ESI-TQ-MS/MS) based on a multiple-reaction monitoring in negative mode. Under optimum UPLC-ESI^--TQ-MS/MS conditions, excellent separation and quantification of 21 constituents were achieved within 20 min on a solid core column with a 1.6 μm particle using pre-column derivatization with a PMP reagent. This method, coupled with enzymatic digestions and principal component analysis, has been successfully applied to characterize and discriminate Ephedra polysaccharides attributed to different species and plant parts. The results suggest that the proposed analytical strategy could achieve a quality evaluation of plant polysaccharides from traditional Chinese medicines.