Liquid ChromatographyMass Spectrometry-based Lipid Profiling Method Development and Application

Lipids comprise a diverse group of biomolecules with various important functions in many different organisms. In the recent years, the importance of lipids for the unterstanding of biochemical relationships with other ‘omics'-fields as well as numerous diseases and pathological conditions has been recognized. Lipidomics has gained importance and thus analytical techniques and methods have been developed. Mass spectrometry (MS) has evolved as the gold standard analytical technique for lipid profiling. Determination of the mass-to-charge ratio (m/z) and generation of diagnostic fragments by tandem-MS enable the lipid identification and structural annotation. Hyphenation with chromatographic methods facilitates the identification of lipid classes and species as well as their isobars and isomers. In the present work, profiling methods for different lipid categories by high performance liquid chromatography (HPLC) coupled to tandem-MS were developed. Separation of phospholipid classes was carried out by hydrophilic interaction liquid chromatograghy (HILIC). These classes were quantifed by an universal phosphorus detection using an inductively coupled plasmatriple quadrupole-MS (ICP-TQ-MS). Complementary molecular information was obtained by electrospray ionization (ESI)-MS. Analysis of algae lipids was performed by reversed phase (RP)-HPLC and HILIC coupled to ESI-MS. Different extraction solvents and cell wall disruption methods were evalutated. Profling of mannosylerythritol lipids as important class of biosurfactants was performed by RP-HPLC-ESI-MS. Structure elucidation was supported by tandem MS.