Determination of triacylglycerol regioisomers using electrospray ionization-quadrupole ion trap mass spectrometry with a kinetic method

[Display omitted] ► This manuscript presents the methodology to distinguish the triacylglycerols regiospecificity. ► The kinetic method associated with the standard addition method was applied. ► The quantification of TAG isomers is possible even if only one TAG standard is available. The kinetic me...

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Bibliographic Details
Published in:Analytica chimica acta 2012-04, Vol.722, p.80-86
Main Authors: Leveque, Nathalie L., Acheampong, Akwasi, Heron, Sylvie, Tchapla, Alain
Format: Article
Language:English
Subjects:
Analytical chemistry
Backbone
Chemistry
Clusters
Correlation
Exact sciences and technology
Ionization
Kinetic method
Kinetics
Mass spectrometry
Oils, Volatile - chemistry
Quantitative analysis
Reference Standards
Regiospecificity
Spectrometric and optical methods
Spectrometry, Mass, Electrospray Ionization - standards
Stereoisomerism
Thermodynamics
Triacylglycerols
Triglycerides - analysis
Triglycerides - standards
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Summary:[Display omitted] ► This manuscript presents the methodology to distinguish the triacylglycerols regiospecificity. ► The kinetic method associated with the standard addition method was applied. ► The quantification of TAG isomers is possible even if only one TAG standard is available. The kinetic method was applied to differentiate and quantify mixtures of regioisomeric triacylglycerols (TAGs) by generating and mass selecting alkali ion bound metal dimeric clusters with a TAG chosen as reference (ref) and examining their competitive dissociations in a quadrupole ion trap mass spectrometer. This methodology readily distinguished pairs of regioisomers (AAB/ABA) such as LLO/LOL, OOP/OPO and SSP/SPS and consequently distinguished sn-1/sn-3, sn-2 substituents on the glycerol backbone. The dimeric complex ions [ref, Li, TAG(AAB and/or ABA)]+ generated by electrospray ionization mass spectrometry were subjected to collision induced dissociation causing competitive loss of either the neutral TAG reference (ref) leading to [Li(AAB and/or ABA)]+ or the neutral TAG molecule (TAG(AAB and/or ABA)) leading to [ref, Li]+. The ratio of the two competitive dissociation rates, defined by the product ion branching ratio (Riso), was related via the kinetic method to the regioisomeric composition of the investigated TAG mixture. In this work, a linear correlation was established between composition of the mixture of each TAG regioisomer and the logarithm of the branching ratio for competitive fragmentation. Depending on the availability of at least one TAG regioisomer as standard, the kinetic method and the standard additions method led to the quantitative analysis of natural TAG mixtures.
ISSN:0003-2670
1873-4324
DOI:10.1016/j.aca.2012.02.016