Figure 5

Our recommended workflow for sample preparation in the studies of targeted human plasma metabolites. 300 μL of human plasma was first deproteinized by 900 μL of 20% methanol/ethanol (step 1); then was incubated on ice for 20 minutes (step 2). After which, the metabolites in the supernatant were obtained and lyophilized at 45°C for 2 hours (step 3). The resulting pellet was subsequently reconstituted with 300 μL of 0.1% formic acid for mass spectrometric analyses (step 4).