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

Abstract

Monosaccharides were derivatized using methylboronic acid and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and the 13C values of these derivatives measured by gas chromatography/combustion/isotope-ratio-monitoring mass spectrometry to determine the original 13C-content of the monosaccharides. Comparison with the measured off-line 13 values of the monosaccharides shows that no fractionation in 13C takes place during derivatization. The methylboronic derivatization method has proven to be a new method for natural abundance isotopic analysis of intact monosaccharides (arabinose, xylose, fucose, fructose and glucose). The method is rapid, does not involve isotopic fractionation during derivatization, and gives more precise 13C values than other methods reported. The method was successfully applied to determine the 13C value of glucose of the freshwater alga Scenedesmus communis