Ultra performance liquid chromatography(UPLC) coupled with orthogonal acceleration time-of-flight(oaTOF) mass spectrometry is becoming an effective and high-throughput analytical technique in metabonomics research.In this paper,an UPLC-oaTOF-MS system was employed to investigate the serum profiles of 40 diabete mellitus(DM)/diabetic nephropathy(DN) patients and 25 healthy volunteers in an effort to find potential biomarkers.The UPLC system produced information-rich chromatograms with typical measured peak widths of 4 s,and generated peak capacities of 225 in 15 min.After the UPLC-oaTOF-MS analysis,principal component analysis(PCA) was used for group differentiation and marker selection.In the projection of positive mode,DM/DN patients and the controls were obviously divided into three groups.Furthermore,two potential markers were identified as phytosphingosine and sphinganine,respectively.Phytosphingosine and sphinganine with decreased concentrations in the patients,were closely related to the sphingolipid metabolism.