Recent Developments of Useful MALDI Matrices for the Mass Spectrometric Characterization of Lipids

Abstract

Matrix-assisted laser desorption/ionization (MALDI) is one of the most successful “soft” ionization methods in the field of mass spectrometry and enables the analysis of a broad range of molecules, including lipids. Although the details of the ionization process are still unknown, the importance of the matrix is commonly accepted. Both, the development of and the search for useful matrices was, and still is, an empirical process, since properties like vacuum stability, high absorption at the laser wavelength, etc. have to be fulfilled by a compound to become a useful matrix. This review provides a survey of successfully used MALDI matrices for the lipid analyses of complex biological samples. The advantages and drawbacks of the established organic matrix molecules (cinnamic or benzoic acid derivatives), liquid crystalline matrices, and mixtures of common matrices will be discussed. Furthermore, we will deal with nanocrystalline matrices, which are most suitable to analyze small molecules, such as free fatty acids. It will be shown that the analysis of mixtures and the quantitative analysis of small molecules can be easily performed if the matrix is carefully selected. Finally, some basic principles of how useful matrix compounds can be “designed” de novo will be introduced.

Relationship between the metabolic and lipid profile in follicular fluid of women undergoing in vitro fertilization

“…The identified species are summarized in Supporting Information data (Tables 1S–2S, respectively, for sera and FF). Several authors reviewed the relevance of ion acquisition mode even in combination with different used matrices (Leopold, Popkova, Engel, & Schiller, 2018). Most of them deal with a negative ion mode especially for triacylglycerols, fatty acids, and some phospholipids.…”

Fast and robust detection of colistin resistance in Escherichia coli using the MALDI Biotyper Sirius mass spectrometry system

“…This system differs from previous Biotyper systems as it can operate in both positive and negative ion modes. Analytes that are acidic in nature, such as those containing phosphate or carboxylate groups, are more efficiently ionized by the generation of anions (16). As such, detection of Lipid A, which contains both long chain fatty acid and phosphate groups (at carbon 1 and 4’), is superior when anions are generated using the negative ion mode.…”

Lipidomics from sample preparation to data analysis: a primer

“…Nevertheless, with the right choice of matrix, MALDI-TOF can quickly deliver data. Examples of matrices that have been found to be advantageous for the ionization of lipids include 2,5dihydroxybenzoic acid, α-cyanocinnamic acid, and a mixture of 9-aminoacridine and N-(1-naphthyl)ethylenediamine hydrochloride [73,74]. Perhaps the biggest advantage of using MALDI in lipidomics is its ability to provide two-dimensional images of the distributions of lipids in tissues.…”