Analysis of 8-aminonaphthalene-1,3,6-trisulfonate-derivatized oligosaccharides by capillary electrophoresis-electrospray ionization quadrupole ion trap mass spectrometry

Dextran was partially hydrolyzed with 0.1 mol/l HCl and the hydrolysate was derivatized with 8-aminonaphthalene-1,3,6-trisulfonate (ANTS) by reductive amination. The derivatized-oligosaccharide mixture was separated by capillary electrophoresis (CE) in a buffer of 1% HAc-NH4OH, pH 3.4, and the separated components were detected on-line by electrospray ionization quadrupole ion trap mass spectrometry (ESI-QIT-MS) in the negative ion mode. A mass accuracy lower than 0.01% could be achieved and as low as 1.6 pmol of detxran octaose could be: detected. ANTS-derivatized dextran oligosaccharide with a degree of polymerization (DP) lower than 6 produced both [M-H](-) and [M-2H](2-) ions, whereas those with a DP of 6 or higher than 6 produced only [M-2H](2-) ion. As 1 less than or equal to DP less than or equal to 6, the percentage of [M-2H](2-) ion in the total ions of [M-H](-) and [M-2H](2-) was found to be a linear function of the logarithmic DP. Molecular mass determination with ESI-QIT-MS strengthens the power of CE analysis of oligosaccharides. (C) 1999 Elsevier Science B.V. All rights reserved.