Identification of heparin oligosaccharides by direct coupling of capillaryelectrophoresis/ionspray-mass spectrometry

A direct coupling between capillary electrophoresis (CE) and ionspray (IS) mass spectrometry (MS) has been optimized to identify oligosaccharides obta ined by enzymatic digestion of heparin, The separation electrolyte was made compatible with the requirements of a direct coupling using electrolytes m ade of ammonium acetate buffer, pH 3.5 and 9.2. The different parameters of the CE/IS interface were optimized using a standard mixture of disaccharid es: flow rate and composition of the sheath liquid, how rate of the sheath gas and position of the capillary in the needle, Different combinations of positive or negative CE voltage polarity and positive or negative MS ioniza tion modes were investigated. They allowed for detection orders to be easil y reversed and for complementary structural information to be gathered, Fin ally, the optimized methodology was applied to the separation and character ization of porcine mucosa heparin depolymerized by heparinases II and III. Copyright (C) 1999 John Wiley & Sons, Ltd.