title: Global analysis of metabolites in rat and human urine based on gas chromatography/time-of-flight mass spectrometry.
abstract: Sediment in urine may contain low-molecular-weight compounds that should be included in the analysis. To date, no systematic investigation has addressed this issue. We investigated three primary factors that influence the extraction efficiency of metabolites during preparation of urine samples for metabolomic research: centrifugation, pH, and extraction solvents. Obtained with the use of gas chromatography/time-of-flight mass spectrometry (GC/TOFMS) technique and principal component analysis (PCA), our results indicate that (1) conventional centrifugation causes an apparent loss of some metabolites, indicating that urine samples for metabolomic research should not be centrifuged before procedures are undertaken to recover the metabolites; (2) pH adjustment has a large impact on the recovery of metabolites and is therefore not encouraged; (3) with design of experiment analysis, methanol and water yield the optimal extraction efficiency. Differences between rat and human urine were observed and are discussed. Ninety-nine metabolites identified in rat and human urine are presented. An efficient protocol is proposed for the pretreatment of urine samples.
authors.affiliation: Center of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, 24 Tongjia Xiang, Nanjing 210009, China.
authors.forename: A
authors.initials: A
authors.lastname: Jiye
authors.forename: Qing
authors.initials: Q
authors.lastname: Huang
authors.forename: Guangji
authors.initials: G
authors.lastname: Wang
authors.forename: Weibin
authors.initials: W
authors.lastname: Zha
authors.forename: Bei
authors.initials: B
authors.lastname: Yan
authors.forename: Hongcan
authors.initials: H
authors.lastname: Ren
authors.forename: Shenghua
authors.initials: S
authors.lastname: Gu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Feng
authors.initials: F
authors.lastname: Shao
authors.forename: Longsheng
authors.initials: L
authors.lastname: Sheng
authors.forename: Jianguo
authors.initials: J
authors.lastname: Sun
mesh_terms: D000328:Adult; D000481:Allantoin / Q000652:urine; D000818:Animals; D003401:Creatine / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006626:Hippurates; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007294:Inositol; D008297:Male; D015999:Multivariate Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D014527:Uric Acid / Q000652:urine; D014556:Urine / Q000737:chemistry*
chemical_list: D006626:Hippurates; D012997:Solvents; D014527:Uric Acid; D000481:Allantoin; D007294:Inositol; D003401:Creatine; C030514:hippuric acid