title: Direct infusion ESI-MS analysis for metabolite profiling of human plasma using various fractionation techniques.
abstract: BACKGROUND
  Metabolomics is a real challenge owing to the complexity and chemical heterogeneity of biological samples. In this study, a comparative analysis of metabolite profiling using ten metabolite extraction techniques were investigated on a pooled plasma sample followed by direct infusion ESI-MS analysis on both positive and negative modes. Methodology & Results: Metabolites from a pooled sample of 50 healthy volunteers were separated one- and two-dimensionally utilizing solvent precipitation, solid-phase extraction and molecular weight fractionation. Numbers of unique metabolites that are specific to a particular sample preparation approach were also identified by online available database, Metlin. The (1)H NMR study of different extraction procedures were also recorded to elaborate the comparative profiling of the various fractionation procedures.
  
  
  CONCLUSIONS
  The results of this study suggest that the metabolite extraction procedures based on 1- and 2-dimensions, followed by direct infusion ESI-MS analysis were able to detect endogenous metabolites belonging to different chemical classes.
authors.affiliation: Dr Panjwani Center for Molecular Medicine & Drug Research, International Center for Chemical & Biological Sciences, University of Karachi, Karachi-75270, Pakistan.
authors.forename: Syed Ghulam
authors.initials: SG
authors.lastname: Musharraf
authors.forename: Amna Jabbar
authors.initials: AJ
authors.lastname: Siddiqui
authors.forename: Shumaila
authors.initials: S
authors.lastname: Mazhar
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D001798:Blood Proteins / Q000737:chemistry; D011232:Chemical Precipitation; D006801:Humans; D008297:Male; D055432:Metabolomics / Q000379:methods*; D010949:Plasma / Q000737:chemistry* / Q000378:metabolism; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D001798:Blood Proteins