2,4-Dinitrophenylhydrazine as a New Reactive Matrix to Analyze Oxidized Phospholipids by MALDI-TOF Mass Spectrometry

Abstract

Matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is increasingly used to analyze native and oxidized lipids. However, as the majority of MALDI devices are operating under high vacuum, the detection of volatile compounds such as “small” aldehydes is difficult and requires previous derivatization. This study uses 2,4-dinitrophenylhydrazine (DNPH) to efficiently convert aldehydes into hydrazones that can be easily identified by the characteristic mass shift and their selective enrichment by precipitation. Additionally, the UV absorption of the hydrazones at 337 nm is sufficiently high allowing direct analysis without typical MALDI matrices. Finally, it will be shown that the presence of DNPH does also enable the detection of non-oxidized phospholipids.

Keywords:

• Fenton chemistry
• Lipid oxidation
• MALDI MS
• Reactive MALDI matrix

Abbreviations:

• DNPH, 2,4-dinitrophenylhydrazine
• DESI, desorption electrospray ionization
• DHB, 2,5-dihydroxybenzoic acid
• 9-AA, 9-aminoacridine
• GPC, glycerophosphatidylcholine
• MS, mass spectrometry
• MALDI-TOF, matrix-assisted laser desorption and ionization time-of-flight
• PL, phospholipid

Acknowledgments

This publication was supported by the Leipzig Interdisciplinary Research Cluster of Genetic Factors, Clinical Phenotypes and Environment (LIFE Center, Universität Leipzig). LIFE is funded by means of the European Union, by the European Regional Development Fund (ERDF) and by means of the Free State of Saxony within the framework of the excellence initiative.