Multi-matrix sample preparation for FAMEs profiling by two-dimensional gas chromatography (GCxGC)
Résumé
Introduction :
Fatty acids methyl esters (FAMEs) analysis is of a special interest for monitoring the metabolic health of a population. As lipidomic studies are often based on the separation of the different lipid classes by LC or GC-HRMS, it appears that the use of a more resolutive chromatographic technique, like two-dimensional gas chromatography (GCxGC), can be beneficial to enhance resolution and improve FAMEs discrimination in lipidomic studies. Therefore, GCxGC was assessed for FAMEs analysis in several matrices.
Material and methods :
Bovine and human matrices (urine, plasma, milk, adipose tissue, feces, liver) were prepared each following 2 protocols. After FAMEs extraction (Bligh & Dyer or Isopropanol precipitation), extracts were derivatized using methoxylamine (MOX) and silylated with trimethylsilyl-N-methyl trifluoroacetamide (MSTFA). GCxGC coupled with both a time-of-flight mass spectrometer and a flame ionization detector (GCxGC-TOF-FID from Markes) was used for FAMEs analysis. Chromatographic separation optimization was assessed through two two-dimensional (1D and 2D columns) settings on a mix of 37 FAMEs. Samples were finally injected and results were compared in terms of separation (resolution), yield and feature annotation, performed with ChromSpace software and NIST database. The suitable FAMEs extraction protocol from the different matrices was selected based on separation quality.
Results and discussion :
The best columns combination was selected and applied to the matrices analysis. As a result, the 37 FAMEs were successfully separated and annotated (level 2) using GCxGC. Moreover, additional FAMEs were detected and annotated in the biological samples. Based on quality of separation, as well as annotation efficiency, the best protocol for each matrix was selected.
Conclusions :
This GCxGC-TOF-FID method for FAMEs profiling in 6 different matrices has been successfully developed, allowing the separation of FAMEs isomers, as well as confident annotation. In the future, the method will be used for FAMEs quantification in several matrices in lipidomic studies.
Domaines
Chimie analytique
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