Determination of glycosaminoglycan monosaccharides by capillary electrophoresis using laser-induced fluorescence detection

A newly developed capillary electrophoretic method using laser-induced fluorescence detection (CE–LIF) for the analysis of monosaccharides released from acid hydrolysis of glycosaminoglycans was studied. The method was compared with a previously published method using indirect LIF detection (CE–ILIF). For the CE–LIF method, electrophoretic conditions for the separation of the monosaccharides derivatised with 8-aminopyrene-1,3,6-trisulfonate (APTS) were optimised. The best separations were obtained using 100 mM acetate at pH 4.5 as running buffer. The influence of the injection vial volume on the precision and stability of the sample in different conditions was studied. The detection limits of the CE–LIF method were found to be 0.4–0.6 nM, while those obtained by CE–ILIF ranged from 11.4 to 14.3 μM. Other quality parameters of the method, such as run-to-run precision, day-to-day precision, and linearity were also determined. Finally, the new method was applied to the analysis of the acid hydrolysis products from a glucosaminoglycan (heparin) and a galactosaminoglycan (dermatan sulfate) and cross-contamination between the two solutions was determined. The high sensitivity of the new method allows the determination of dermatan sulfate contaminations in a heparin raw sample down to 0.04% (w/w) and broadens the practical applicability of CE–LIF for the quantitation of the endogenous levels of glycosaminoglycans in animal samples and for pharmacokinetic control after therapeutical heparin administration.