2.4. Metabolomics Data Preprocessing

The UHPLC-HRMS data was processed by Progenesis QI (version 2.1, Waters Corporation, Milford, MA, USA) for peak picking and alignment. Background signals were excluded by removing peaks with a higher mean intensity of the blanks, as compared to the QCSPs based on the unnormalized data. The data was normalized to a reference study pool sample using the “normalize to all” function in Progenesis, and signals with a relative standard deviation (RSD) > 50% across study pool replicates were excluded from further analysis [18].