Application of MALDI-TOF mass spectrometry in lipidomics

Lipids are of high interest on different levels. First, lipids as triacylglycerols (TAG) (particularly different vegetable oils) are of immense commercial interest. Second, lipids are of high relevance for different in vivo processes. For instance, the diagnostics of changes of the lipoproteins of human blood is very important in vascular diseases, whereas phospholipids (PL) are crucial for the properties of the cellular membrane and some selected Ill. were also recognized to represent important second messengers. Although there are many different methods (including different chromatographic and spectroscopic approaches) available, mass spectrometry (MS) is the most versatile tool of lipid analysis, with or without prior separation steps. Although several different ionization techniques are capable of producing ions from the lipids of interest, matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) MS is the simplest and most convenient method. This review gives a short methodological survey of the capabilities and drawbacks of MALDI-TOF MS and discusses its role in lipidomic studies. Although a summary about PI, analysis will also be given, the focus of this review is the analysis of apolar lipids as TAG, cholesterol and cholesteryl esters. Aspects of sample preparations and the avoidance of pitfalls are also highlighted. Finally, it is the aim of this paper to show that MALDI MS provides data comparable to other modern MS methods, but in a faster and more convenient way.