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A metabolomic based approach has been established for metabolite profiling and biomarker discovery,however,it is equally applicable to food science for quantitative characterization of food quality.Brewing and fermentation product contains several polar metabolites such as amino acids,nucleic acid related compounds and organic acids,which provide important contribution on the products quality,flavor and being useful index of a fermentation performance.Liquid chromatography-mass spectrometry is one of a widely used tool in the field of metabolomics and metabolite profiling.We developed an LC-based approach to determine metabolite profiles including polar metabolites and to identify specific endogenous components,aiming at high throughput and comprehensive methods using TOFMS acquisition.Seventeen products of commercial beer and related beverage were used as a test sample for the polar metabolite analysis.Several organic acids and nucleic acid related compounds were used as standards for method development.Mass accuracy of instrument,LCMS-IT-TOF was checked with the known compound such as malic acid and adenosine,it turned out that MS measurement was performed in the accuracy of less than 3 ppm(using external calibration)acquired with fast polarity switching.912 peaks were detected by peak extraction function from positive mode and 528 peaks in negative mode.To determine sample and metabolite profiles,principal component analysis was performed with unique peaks.Four experimental groups categorized in Japan by malt content(high-malt beer,beer,low-malt beer and the third beer)were roughly classified into three clusters.The accurate mass,MSn and isotope ratio information from IT-TOFMS also gave tentative assignment of metabolites.In conclusion,PCA of LCMS data of beer resulted in the separation of samples according to some of their different compositional properties.