Pressure-assisted capillary electrophoresis–electrospray ion trap mass spectrometry for the analysis of heparin depolymerised disaccharides

A pressure-assisted capillary electrophoresis–ion trap mass spectrometry method was developed for the analysis of eight heparin-derived disaccharides. A 30 mM formic acid buffer at pH 3.20 was selected as running electrolyte, and the separation was performed by the simultaneous application of a CE voltage of −30 kV and an overimposed pressure of 0.5 p.s.i. (3.45 kPa). The application of pressure assistance was needed to provide stable electrospray conditions for successful coupling. The linearity of the CE–MS and CE–MS–MS methods was checked under these conditions. Quality parameters such as run-to-run precision and limits of detection were established in both CE–MS and CE–MS–MS modes. Finally, enzymatically depolymerised bovine and porcine mucosal heparins were analysed in this CE–MS system and the characteristic relative molar percentages of major and minor disaccharides were calculated.