Gas chromatography/combustion/isotope-ratio-monitoring mass spectrometric analysis of methylboronic derivatives of monosaccharides: a new method for determining natural C-13 abundances of carbohydrates

Monosaccharides were derivatized using methylboronic acid and N,O-bis (trim ethyisilyl)trifluoroacetamide (BSTFA), and the delta C-13 values of these d erivatives measured by gas chromatography/ combustion/isotope-ratio-monitor ing mass spectrometry to determine the original C-13-content of the monosac charides. Comparison with the measured off-line delta (13) values of the mo nosaccharides shows that no fractionation in C-13 takes place during deriva tization. The methylboronic derivatization method has proven to be a new me thod for natural abundance isotopic analysis of intact monosaccharides (ara binose, xylose, fucose, fructose and glucose). The method is rapid, does no t involve isotopic fractionation during derivatization, and gives more prec ise delta C-13 values than other methods reported. The method was successfu lly applied to determine the delta C-13 value of glucose of the freshwater alga Scenedesmus communis. Copyright (C) 2001 John Wiley & Sons, Ltd.