A new update of MALDI-TOF mass spectrometry in lipid research

Matrix-assisted laser desorption and ionization (MALDI) mass spectrometry (MS) is an indispensable tool in modern lipid research since it is fast, sensitive, tolerates sample impurities and provides spectra without major analyte fragmentation. We will discuss some methodological aspects, the related ion-forming processes and the MALDI MS characteristics of the different lipid classes (with the focus on glycerophospholipids) and the progress, which was achieved during the last ten years. Particular attention will be given to quantitative aspects of MALDI MS since this is widely considered as the most serious drawback of the method. Although the detailed role of the matrix is not yet completely understood, it will be explicitly shown that the careful choice of the matrix is crucial (besides the careful evaluation of the positive and negative ion mass spectra) in order to be able to detect all lipid classes of interest. Two developments will be highlighted: spatially resolved Imaging MS is nowadays well established and the distribution of lipids in tissues merits increasing interest because lipids are readily detectable and represent ubiquitous compounds. It will also be shown that a combination of MALDI MS with thin-layer chromatography (TLC) enables a fast spatially resolved screening of an entire TLC plate which makes the method competitive with LC/MS.

Automated summary

Matrix-assisted laser desorption and ionization (MALDI) mass spectrometry (MS) is a valuable tool in lipid research due to its speed, sensitivity, and ability to tolerate impurities. This article discusses the methodology, ion-forming processes, and characteristics of different lipid classes in MALDI MS, with a focus on glycerophospholipids. The article also highlights the progress made in the last decade, particularly in the quantitative aspects of MALDI MS. The careful choice of matrix and the combination of MALDI MS with thin-layer chromatography (TLC) are emphasized as important factors for successful lipid detection.