Hydrophilic interaction chromatography coupled to nuclear magnetic resonance spectroscopy and mass spectroscopy--a new approach for the separation and identification of extremely polar analytes in bodyfluids

A method for the unambiguous identification of highly polar molecules based on the separation on a silica gel column run in hydrophilic interaction chromatography (HILIC) mode followed by mass spectroscopic (MS) analysis and subsequent measurement by nuclear magnetic resonance (NMR) spectroscopy is described. Polar neutral, acidic and basic compounds of small molecular size usually not retained on reversed phase stationary phases can be separated and unequivocally identified by means of MS and NMR spectroscopy. The method is applied to exemplify the identification of the endogenous metabolite trigonelline and the polar antibiotic amoxicilline in human urine.