Determination of the 13C-labeling pattern of glucose by gas chromatography-mass spectrometry.

We developed a gas chromatography-mass spectrometric method which allows to determine the complete 13C-labeling pattern of glucose. The method uses four derivatives of glucose (methyloxime trimethylsilyl, bisbutylboronate acetate, aldonitrile pentaacetate, and permethyl) and selective analysis of fragment ions retaining specific carbon atoms. The technique was tested by analyzing glucose from rat livers perfused with various 13C tracers. The labeling patterns agree with theoretical calculations and with literature reports where [14C]glucose was analyzed by degradation and [13C]glucose was analyzed by NMR.