NANOMOLAR DETERMINATION OF AMINATED SUGARS BY CAPILLARY ELECTROPHORESIS

A procedure is described for the determination of aminated monosacchar ides at nanomolar concentrations by derivatization with the fluorogeni c reagent 3-(p-carboxybenzoyl)quinoline-2-carboxyaldehyde (CBQCA) to p roduce a fluorescent derivative that can be identified and detected by capillary electrophoresis with laser-induced fluorescence detection. Labeling conditions that favor the formation of the CBQCA-aminated sug ar derivative over secondary fluorescent products were chosen. Samples as dilute as 1.0 x 10(-9) M 1-glucosamine were analyzed. The results can be extended to other aminated monosaccharides since they showed si milar reaction yields on labeling. The capability for the analysis of mixtures of aminated sugars was also demonstrated. Five labeled aminat ed sugars were separated by capillary electrophoresis using a running buffer containing a mixture of phenyl boronate and berate. The detecti on scheme was based on a low-scattering sheath flow cuvette as a postc olumn detector and two photomultiplier tubes that have mutually exclud ed wavelength ranges to prevent the water Raman band from contributing to the background signal. The system had a limit of detection of 75 z eptomol of fluorescently labeled 1-glucosamine.