The stereoselective reaction of 11 monosaccharides D-ribose, D-lyxose, D-xylose, L-arabinose, L-rhamnnose, L-fucose, D-glucose, D-mannose, D-galactose, D-fructose, L-sorbose with butaneboronic acid was studied by fast atom bombardment mass spectrometry (FAB MS). Characteristic mass spectra of the derivatized monosaccharides showed some differences which could be used in the differentiation of the stereoisomers in FAB MS. This reaction was effected by the orientation of OH groups and the favored configuration (furanose or pyranose) of monosaccharides, 1-hydroxyl groups also participated in the reaction if 2 and 3-OH groups are in the trans-positions.

Key words: MASS SPECTROGRAPHY, BUTYL GROUP, MONOSACCHARIDE, STEREOISOMERISM, BORONIC ACIDS P