The accurate determination of serum glucose by isotope dilution mass spectrometry—two methods

Two isotope dilution mass spectrometric methods have been developed for the determination of D-glucose in human serum. Each uses a uniformly labeled (13C)glucose as the internal standard. The first method involves conversion of glucose into 1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose and an extensive clean-up, followed by quantitation using packed column gas chromatography mass spectrometry. In the second method, glucose is converted into alpha-D-glucofuranose cyclic 1,2:3,5-bis(butylboronate)-6-acetate. The wet chemistry work-up is simpler, but analysis by capillary gas chromatography mass spectrometry is required. Both methods exhibit excellent precision (coefficients of variation less than 0.3%) and provided mean values that agree within 1% for all serum pools tested.