Many lipidomic approaches focus on investigating aspects of
sphingolipid metabolism. Special emphasis is put on neutral
sphingolipids and
cholesterol and their interaction. Such an interest is attributed to the fact that those
lipids are altered in a series of serious disorders including various
sphingolipidoses. High performance thin-layer chromatography (HPTLC) has become a widely used technique for
lipid analysis. However, mass spectrometric profiling is irreplaceable for gaining an overview about the various molecular species within a
lipid class. In this work we have developed a sensitive method based on a gradient normal phase high performance liquid chromatography (HPLC) coupled to quadrupole time of flight (QTOF) atmospheric pressure chemical ionization mass spectrometry (APCI-MS) in positive mode, which for the first time enables separation, on-line detection, and mass spectrometric profiling of multiple neutral
sphingolipids including
ceramide,
glucosylceramide,
lactosylceramide,
globotriaosylceramide,
globotetraosylceramide,
sphingomyelin as well as
cholesterol within less than 15min. An important advantage of the presented HPLC/APCI-MS approach is that the separation pattern emulates the one obtained by an optimized HPTLC method with a multiple stage development. Thus, the
lipid classes previously separated and quantified by HPTLC can be easily screened regarding their mass spectrometric profiles by HPLC/APCI-MS. In addition, the selected ionization conditions enable in-source fragmentation providing useful structural information. The methods (HPLC/APCI-MS and the optimized HPTLC) were applied for the analysis of the mentioned
lipids in human fibroblasts. This approach is aimed basically at investigators who perform studies based on genetic modifications or treatment with pharmacological agents leading to changes in the biochemical pathways of neutral
sphingolipids and
cholesterol. In addition, it can be of interest for research on disorders related to impairments of
sphingolipid metabolism.