Structural Elucidation and Relative Quantification of Fatty Acid Double Bond Positional Isomers in Biological Tissues...

Area of Science:

• Analytical Chemistry
• Biochemistry
• Structural Biology

Background:

• Fatty acids (FAs) exhibit significant structural diversity, with variations linked to disease states.
• Accurate FA identification is crucial for understanding their biochemical roles in disease progression.
• Conventional tandem mass spectrometry (MS/MS) lacks sufficient structural detail for comprehensive FA analysis.

Purpose of the Study:

• To develop an alternative dissociation method for improved FA structural characterization.
• To utilize gas-phase charge inversion ion/ion reactions for enhanced fragmentation.
• To differentiate monounsaturated fatty acid isomers and perform relative quantification.

Main Methods:

• Employing ion/ion reactions between FA anions and magnesium tris-phenanthroline [Mg(Phen)3] dications.
• Inducing charge remote fragmentation of carbon-carbon bonds along the FA chain.
• Localizing carbon-carbon double bond (C=C) positions for isomer differentiation.

Main Results:

• Successfully differentiated monounsaturated fatty acid isomers by localizing C=C bond positions.
• Enabled relative quantification of FA isomers in various biological tissues.
• Observed variations in FA 18:1 (9) abundance across rat brain regions, kidney, and mouse pancreas.
• Determined higher relative abundance of FA 16:1 (9) in human skin dermis compared to sebaceous glands.

Conclusions:

• The developed ion/ion reaction method provides enhanced structural information for fatty acids.
• This technique is valuable for differentiating FA isomers and understanding their distribution in biological systems.
• The findings contribute to a deeper understanding of FA roles in health and disease.