Characterization of Triacylglycerol Estolide Isomers Using High-Resolution Tandem Mass Spectrometry with Nanoelectrospray Ionization

Lukáš Cudlman; Aleš Machara; Vladimír Vrkoslav; Miroslav Polášek; Zuzana Bosáková; Stephen J Blanksby; Josef Cvačka

doi:10.3390/biom13030475

Characterization of Triacylglycerol Estolide Isomers Using High-Resolution Tandem Mass Spectrometry with Nanoelectrospray Ionization

Biomolecules. 2023 Mar 3;13(3):475. doi: 10.3390/biom13030475.

Authors

Lukáš Cudlman^{1

2}, Aleš Machara¹, Vladimír Vrkoslav¹, Miroslav Polášek³, Zuzana Bosáková², Stephen J Blanksby⁴, Josef Cvačka^{1

2}

Affiliations

¹ Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Flemingovo Náměstí 542/2, 166 00 Prague 6, Czech Republic.
² Department of Analytical Chemistry, Faculty of Science, Charles University, Hlavova 2030/8, 128 43 Prague 2, Czech Republic.
³ J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
⁴ School of Chemistry and Physics and the Central Analytical Research Facility, Queensland University of Technology, Brisbane, QLD 4000, Australia.

Abstract

Triacylglycerol estolides (TG-EST) are biologically active lipids extensively studied for their anti-inflammatory and anti-diabetic properties. In this work, eight standards of TG-EST were synthesized and systematically investigated by nanoelectrospray tandem mass spectrometry. Mass spectra of synthetic TG-EST were studied with the purpose of enabling the unambiguous identification of these lipids in biological samples. TG-EST glycerol sn-regioisomers and isomers with the fatty acid ester of hydroxy fatty acid (FAHFA) subunit branched in the ω-, α-, or 10-position were used. Ammonium, lithium, and sodium adducts of TG-EST formed by nanoelectrospray ionization were subjected to collision-induced dissociation (CID) and higher-energy collisional dissociation (HCD). Product ion spectra allowed for identification of fatty acid (FA) and FAHFA subunits originally linked to the glycerol backbone and distinguished the α-branching site of the FAHFA from other estolide-branching isomers. The ω- and 10-branching sites were determined by combining CID with ozone-induced dissociation (OzID). Lithium adducts provided the most informative product ions, enabling characterization of FA, hydroxy fatty acid (HFA), and FAHFA subunits. Glycerol sn-regioisomers were distinguished based on the relative abundance of product ions and unambiguously identified using CID/OzID of lithium and sodium adducts.

Keywords: collision-induced dissociation; estolide-branching isomers; glycerol sn-regioisomers; high-resolution mass spectrometry; higher-energy collisional dissociation; ozone-induced dissociation; triacylglycerol estolides.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Fatty Acids / chemistry
Glycerol
Ions
Lithium / chemistry
Ozone* / chemistry
Sodium
Tandem Mass Spectrometry* / methods
Triglycerides / chemistry

Substances

Triglycerides
Glycerol
Lithium
Fatty Acids
Ozone
Sodium
Ions

Grants and funding

This research was funded by the Grant Agency of Charles University, project SVV and project GAUK 348721. The research was also funded by the European Regional Development Fund, OP RDE (project CZ.02.1.01/0.0/0.0/16_019/0000729), the European Social Fund; OP RDE; Project: “IOCB Mobility II” (No. CZ.02.2.69/0.0/0.0/18_053/0016940) and by the project National Institute for Research of Metabolic and Cardiovascular Diseases (Programme EXCELES, ID Project No. LX22NPO5104)—Funded by the European Union—Next Generation EU.