Sensitive determination of rhodamine 110-labeled monosaccharides in glycoprotein by capillary electrophoresis with laser-induced fluorescence detection

Rhodamine 110 (Rho110) has been used in the highly sensitive analysis of monosaccharides, as it reacts with the reducing carbonyl group of the saccharides. The monosaccharide derivatives were investigated by capillary electrophoresis with laser-induced fluorescence detection. The derivatization was performed at 90 °C for 30 min for all monosaccharides. The derivatized monosaccharides were separated using 200 mM borate (pH 10.5) as running buffer within 20 min. The fluorescence intensities of Rho110-derivatives were significantly decreased by the presence of excess reducing agent, but were greatly increased by the addition of potassium hexacyanoferrate(III). The concentration and mass detection limits for monosaccharides were in the range of 1.4–2.8 nM and 36–70 amol, respectively. We have applied this derivatization method to the analysis of the composition of monosaccharides in glycoproteins (ribonuclease B, fetuin, and erythropoietin) following their subjection to strong acid hydrolysis. The results from these analyses were in good agreements with the reported values established previously.