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In respect of the manifold involvement of lipids in biochemical processes, the analysis of intact and underivatised lipids of body fluids as well as cell and tissue extracts is still a challenging task, if detailed molecular information is required. Therefore, the advantage of combined use of high-pressure liquid chromatography (HPLC), mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectroscopy will be shown analyzing three different types of extracts of the ubiquitous membrane component phosphatidylcholine. At first, different reversed phase modifications were tested on phosphatidylcholines (PC) with the same effective carbon number (ECN) for their applicability in lipid analysis. The results were taken to improve the separation of three natural PC extract types and a new reversed phase (RP)-HPLC method was developed. The individual species were characterized by one- and two-dimensional NMR and positive or negative ion mode quadrupole time of flight (q-TOF)-MS as well as MS/MS techniques. Furthermore, ion suppression effects during electrospray ionisation (ESI), difficulties, limits, and advantages of the individual analytical techniques are addressed.

Sphingomyelins were characterized using a combination of a novel isocratic reversed-phase HPLC method with electrospray time-of-flight mass spectrometric detection and optional online MS/MS. The constitution of the sphingomyelins is determined by MS/MS experiments. Baseline separation of 17 compounds of a bovine brain extract (2 main compounds and 15 minor or trace compounds) was achieved with a mobile phase consisting of methanol, 2-propanol, THF, and water on a RP-18-phenyl column. In parallel, the HPLC fraction were sampled to a 600-MHz NMR spectrometer to acquire 1D and 2D NMR spectra and to elucidate the molecular structure of individual sphingomyelin components.

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