Development of MS-based analytical approaches for targeted/untargeted analysis of metabolites and bioactive compounds applied to different scientific fields

This PhD thesis explores the power of analytical methodologies, particularly GC-MS and LC-MS/MS, in understanding biological systems. The initial chapter lays the groundwork by establishing core concepts in analytical chemistry and metabolomics. It emphasizes the crucial role of mass spectrometry in deciphering the complexities of biological systems. A significant focus of the thesis is the development and validation of targeted analytical methods. Chapter 3 details the creation of an LC-MS/MS method designed to quantify bile and oxo-bile acids in fecal samples. Subsequent chapters showcase the application of these methods in various contexts. Chapter 4 demonstrates the use of the bile acid method in a study of dogs suffering from chronic inflammatory enteropathy. By applying this method, researchers aimed to identify potential biomarkers indicative of the pathological state. Chapter 5 presents the development and validation of an LC-MS/MS method for quantifying pollutants in mussels, a common food source. This section explores the challenges of creating a multiresidue method and introduces a novel sample treatment approach. The validated method was then applied in environmental research to assess pollutant accumulation in mussels, providing valuable insights into environmental safety. Chapter 6 highlights the application of GC-MS in a biomedical context. It details the use of this technique to quantify SCFA in a mouse model of Fabry disease exemplifying the potential of GC-MS for disease research and biomarker identification. Chapter 7 emphasizes the crucial role of targeted and untargeted metabolomics in clinical research. It details a comprehensive analysis to identify and quantify biomarkers related to the severity of COVID-19. Overall, this thesis emphasizes the power of targeted and untargeted metabolomics in unveiling the intricate workings of biological systems. The developed and validated analytical methods pave the way for further research in disease diagnosis, environmental monitoring, and food safety.