“…. Supernatant, 5 μL, was injected for analysis after centrifugation.To examine the influence of extraction fold (tissue/mg: solution/ μL) on extracted metabolites, four folds were compared(Cai et al, 2016;Liu et al, 2015;Lu et al, 2013). Liver samples (50 mg) were first homogenized in 200 μL ice-cold water followed by addition of 300 μL methanol (MeOH; M1), 500 μL 50% acetonitrile (ACN; M2), 500 μL 80% ACN (M3), 500 μL 50% MeOH (M4) and 500 μL 80% MeOH (M5).After the supernatant (150 μL) had been diluted with 150 μL chilled 100% ACN and vortexed for 20 min, the mixture was centrifuged.Owing to supernatant frequently being treated by drying and redissolution, eight resuspension solutions were designed for comparison (Garcia-Canaveras, Donato, Castell, & Lahoz, 2011; Huang et al, 2011; Jeong et al, 2015; Masson et al, 2010).…”