Fig. 2

Data quality control for analysis of targeted metabolomics and the distribution of the metabolite concentrations in all the FFs. A The distribution of the cumulative frequency of the CV for the relative retention time in the QC samples. The Y-axis represents the cumulative frequency of the CV, and the X-axis denotes the CVs for the relative retention time. B The distribution of the cumulative frequency of the CV for the metabolite concentrations in the QC samples. The Y-axis represents the cumulative frequency, and the X-axis stands for the CV for the metabolite concentrations. C, D Concentration boxplots for all the targeted metabolites quantified in all the FFs. The Y-axis represents the concentrations (ng/ml) after log10 transformation, and the X-axis denotes the metabolites. AA, amino acid; ACR, acyl carnitine; BA, biological amine; HO, hormone; SP, sphingolipid; HE, hexose; Vit, water-soluble and fat-soluble vitamins; PC, phosphatidylcholine