Liquid chromatography-mass spectrometry based metabolomics, lipidomics and epitranscriptomics.

Metabolomics and lipidomics are the comprehensive studies of metabolites and lipids in cells, biological fluids, tissues, or organisms. These distinct chemical fingerprints are left behind by cellular processes. Epitranscriptomics is the field that focuses on examining chemical modifications on RNA molecules at the transcriptome level. Liquid chromatography-mass spectrometry (LC-MS) has been widely used in those omics studies. In this dissertation, I developed and applied both untargeted and targeted approaches using LC-MS based various analytical platforms to conduct omics studies. Firstly, I investigated caffeine metabolites in human urine and discovered three potential functional biomarkers to differentiate the stages of alcohol-associated liver disease (ALD). Secondly, I investigated tryptophan metabolic pathway changes in the urine of patients with different stages of ALD. Thirdly, I developed an open-source analysis software for comprehensive two-dimensional liquid chromatography-mass spectrometry (2DLC-MS) based lipidomics. And finally, I developed a comprehensive 2DLC-MS platform for RNA oligonucleotides analysis using strong anion exchange chromatography (SAX) coupled with ion paring reversed phase chromatography (IP-RPC).