Lipidanalyse von Bioflüssigkeiten durch kombinierte SPE/HPLC-, MS- und NMR-Techniken

Abstract

Body fluids like blood plasma are easy to gain and reflect the metabolic state of an organism. One of the challenging tasks is the analysis of intact and underivatized lipids, which have various important functions in organism (energy storage, membrane building block, cellular signalling, precursor of relevant biomolecules etc.). The lipid composition consists of different, structural diverse lipid classes with several subclasses including numerous lipid species. These species vary in chain length, degree of saturation and/or kind of bonding of the attached fatty acid(s). Anomalous lipid compositions were correlated to different diseases like diabetes and many others. In the present work a hyphenated approach consisting of different separation (SPE, HPLC) and analytical techniques (MS, NMR) was applied for the investigation of lipids in body fluids. Such an approach combines the advantages of the different techniques resulting in increased selectivity, sensitivity and structure elucidation power. The thesis shows the way from finding a suitable lipid extraction method to the identification of individual lipid species in blood plasma and serum samples with a main focus on method development and optimization. Beside several SPE and LC-MS methods for the separation of various lipid groups, classes or species, a new isocratic HILIC-ESI-MS method for the class separation of phospholipids is mentionable. Furthermore, the analytic procedure was used for lipid analysis of diabetic mouse samples (diabetes mellitus type 2) to demonstrate the application for samples with pathological background. Detailed experimental features and results obtained on different lipids are part of this work.