High-performance liquid chromatographic separation of 8-aminopyrene-1,3,6-trisulfonic acid labeled N-glycans using a functional tetrazole hydrophilic interaction liquid chromatography column.

8-Aminopyrene-1,3,6-trisulfonate (APTS) is one of the most frequently used reagent in capillary electrophoresis. Three sulfonate groups in APTS generate fast electrophoretic mobilities of derivatized glycans, therefore very suitable for CE-LIF applications. However, these groups also make separation with partition chromatography difficult. A novel column for hydrophilic interaction liquid chromatography (HILIC) with an anionic tetrazole functionalized polymer-based silica was examined for the separation of APTS-labeled glycans derived from specific glycoproteins. This separation mode has enhanced capability for the size resolution of neutral and acidic oligosaccharides. In addition, specific glycan isomers, which are usually difficult to separate with HILIC methods, were also separated. IgG-derived complex-type glycans that have an isomeric pair of monogalactosylated glycans, as well as differences in the number of galactose residues, are separable using this mode. We also utilized this column for the fractionation of APTS-labeled glycans from porcine thyroglobulin and examined their migration times with CE by co-migration with a mixture of glycoprotein glycans. Combinational modes of HILIC and anionic repulsion show promise for the separation and preparation of glycoprotein-derived glycans labeled with APTS.