Fig. 2

Coverage and quality analysis of plasma vs. serum through different extraction methods. The putative metabolite and « biologically unmeaningful noise level» peaks are analyzed following four LC–MS conditions: (i) + ESI HILIC, (ii) − ESI HILIC, (iii) + ESI RP C18 and, (iv) − ESI RP C18 within each extraction methods for plasma and serum. For total number of putative metabolites detected is analyzed after removal of features present in blank extracts.1: methanol extraction methods; 2: methanol:acetonitrile extraction methods; 3: acetonitrile extraction methods; 4: hybrid-SPE extraction method with acetonitrile; 5: hybrid-SPE extraction method with methanol