Investigations on the migration behavior of insulin and related synthetic analogues in CZE, MEKC and MEEKC employing different surfactants.

The retention/migration behavior of insulin and five synthetic insulin analogues in CZE, MEKC and MEEKC employing seven different detergents within the latter two techniques has been investigated. Substantial changes in separation selectivity in MEKC could be observed for several insulins when moving from SDS to cholate-based micellar systems. Customized separations could be achieved by using mixtures of SDS and deoxycholate.

Determination of sialic acids released from glycoproteins using capillary zone electrophoresis/electrospray ionization mass spectrometry.

A simple method for the determination of the two most abundant sialic acids released from glycoproteins based on CZE-MS is presented. Several parameters like BGE with various organic modifiers and sheath liquids were studied with respect to their suitability for the fast and easy analysis of the selected compounds by CZE-MS. Finally, a BGE containing 10 mM ammonium acetate allowed the quantification of N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) in glycoproteins as well as human plasma samples.

Analysis of glycans in glycoproteins by diffusion-ordered nuclear magnetic resonance spectroscopy.

Enzymatically cleaved glycans from sub-milligram quantities of erythropoietin (EPO) and ovalbumin have been analyzed, without further purification, by two-dimensional diffusion-ordered nuclear magnetic resonance spectroscopy. At NMR sample concentrations below 50 micromol L-1 the major components of the oligosaccharide fractions could be distinguished by their anomeric proton chemical shift and their size-dependent diffusion coefficients.