Multi-cationic aminopyrene-based labeling tags for oligosaccharide analysis by capillary electrophoresis-mass spectrometry.

In this work, new multi-cationic aminopyrene-based labeling tags were designed and synthesized for oligosaccharide analysis by capillary electrophoresis-mass spectrometry (CE-MS). The starting compound, 8-aminopyrene-1,3,6-trisulfonic acid trisodium salt, was modified in order to form a sulfonamide derivative having three tertiary amines in the label structure. The sulfonamide derivative was further methylated to generate three permanently charged quaternary ammonium moieties on the label. The synthesized labels were characterized by NMR, IR, UV/Vis, fluorescence spectroscopy and mass spectrometry. Furthermore, the labels were applied for maltooligosaccharide standards as well as N-linked glycans labeling via reductive amination and followed by CE-MS analysis. The CE-MS analysis of maltooligosaccharides labeled by these newly synthesized labels provided the sub-micromolar limit of detection based on the extracted ion electropherogram signals.