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Analysis of reducing carbohydrates by reductive tryptamine derivatization prior to micellar electrokinetic capillary chromatography

Andersen, K.E., Bjergegaard, C., Sorensen, H.
Journal of agricultural and food chemistry 2003 v.51 no.25 pp. 7234-7239
Lupinus angustifolius, chemical analysis, food analysis, reducing sugars, carbohydrates, pentoses, hexoses, uronic acids, disaccharides, deoxysugars, chemical reactions, tryptamine, chromatography
A micellar electrokinetic capillary chromatography method for determination of low molecular weight carbohydrates (dp 1-2) with an unbound carbonyl group as in aldoses or other reducing carbohydrates has been developed. Reductive amination of aldoses on the carbonyl group using tryptamine introduced a chromophor system to the carbohydrates enabling their sensitive UV detection at 220 nm and identification based on the indole group using diode array detection. Twelve carbohydrates including pentoses (D-ribose, L-arabinose, and D-xylose), hexoses (D-glucose, D-mannose, and D-galactose), deoxy sugars (L-rhamnose and L-fucose), uronic acids (D-glucuronic acid and D-galacturonic acid), and disaccharides (cellobiose and melibiose) are included in the study, using D-thyminose (2-deoxy-D-ribose) as the internal standard. Detection of all 12 carbohydrates is performed within 30 min. Linearity with correlation coefficients from 0.9864 to 0.9992 was found in the concentration range of 25-2500 micromol/L for all carbohydrates; the relative standard deviation on the migration times was between 0.27 and 0.80 min, and limits of quantification and limits of determination were in the picomole range.