LC-MS/MS-Based Untargeted Hydrophilic Metabolomics Using MS-DIAL.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is widely used in the field of metabolomics because it enables the simultaneous detection of hundreds to thousands of metabolites in a single analysis. MS-DIAL 5 is a software platform that facilitates the analysis of mass spectrometry data, including those obtained from LC-MS/MS, and provides a function for creating molecular spectral networks. In the analysis of hydrophilic metabolites, the availability of standard compounds is limited compared with that of lipids, and the utilization of MS/MS libraries is often restricted. To address this challenge, molecular spectral networking serves as an effective strategy for extending annotations to unknown ions. In this chapter, we introduce an analytical strategy for hydrophilic metabolite analysis using MS-DIAL 5, which utilizes retention time prediction and molecular spectral networking to enhance the reliability and comprehensiveness of metabolite annotation.