HYDROPHILIC-INTERACTION CHROMATOGRAPHY OF COMPLEX CARBOHYDRATES

Complex carbohydrates can frequently be separated using hydrophilic-in teraction chromatography (HILIC). The mechanism was investigated using small oligosaccharides and a new column, PolyGLYCOPLEX. Some carbohyd rates exhibited anomer separation, which made it possible to determine the orientation of the reducing end relative to the stationary phase. Amide sugars were consistently good contact regions. Relative to amid e sugars, sialic acids and neutral hexoses were better contact regions at lower levels of organic solvents than at higher levels. HILIC read ily resolved carbohydrates differing in residue composition and positi on of linkage. Complex carbohydrate mixtures could be resolved using v olatile mobile phases. This was evaluated with native glycans and with glycans derivatized with 2-aminopyridine or a nitrobenzene derivative . Both asialo- and sialylated glycans could be resolved using the same set of conditions. With derivatized carbohydrates, detection was poss ible at the picomole level by UV detection or on-line electrospray mas s spectrometry. Selectivity compared favorably with that of other mode s of HPLC. HILIC is promising for a variety of analytical and preparat ive applications.