Accurate quantification of lipid species affected by isobaric overlap in Fourier-transform mass spectrometry

Journal of Lipid Research

Sabrina Krautbauer¹  Christer S. Ejsing²  Marcus Höring³  Verena M. Ertl³  Ralph Burkhardt³  Gerhard Liebisch³ 

[1] Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany;Department of Biochemistry and Molecular Biology, Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark;Institute of Clinical Chemistry and Laboratory Medicine, Regensburg University Hospital, Regensburg, Germany;

关键词: lipidomics;    mass spectrometry;    lipids;    phospholipids;    sphingolipids;    triglycerides;   

DOI  :  

来源: DOAJ

【 摘 要 】

Abstract: Lipidomics data require consideration of ions with near-identical masses, which comprises among others the Type-II isotopic overlap. This overlap occurs in series of lipid species differing only by number of double bonds (DBs) mainly because of the natural abundance of 13C-atoms. High-resolution mass spectrometry, such as Fourier-transform mass spectrometry (FTMS), is capable of resolving Type-II overlap depending on mass resolving power. In this work, we evaluated FTMS quantification accuracy of lipid species affected by Type-II overlap. Spike experiments with lipid species pairs of various lipid classes were analyzed by flow injection analysis-FTMS. Accuracy of quantification was evaluated without and with Type-II correction (using relative isotope abundance) as well as utilizing the first isotopic peak (M+1). Isobaric peaks, which were sufficiently resolved, were most accurate without Type-II correction. In cases of partially resolved peaks, we observed peak interference causing distortions in mass and intensity, which is a well-described phenomenon in FTMS. Concentrations of respective species were more accurate when calculated from M+1. Moreover, some minor species, affected by considerable Type-II overlap, could only be quantified by M+1. Unexpectedly, even completely unresolved peaks were substantially overcorrected by Type-II correction because of peak interference. The described method was validated including intraday and interday precisions for human serum and fibroblast samples. Taken together, our results show that accurate quantification of lipid species by FTMS requires resolution-depended data analysis.

【 授权许可】

Unknown