Rapid measurement of plasma free fatty acid concentration and isotopic enrichment using LC/MS

Xuan Mai T. Persson, Agnieszka Urszula Błachnio-Zabielska, Michael D. Jensen

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


Measurements of plasma free fatty acids (FFA) concentration and isotopic enrichment are commonly used to evaluate FFA metabolism. Until now, gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) was the best method to measure isotopic enrichment in the methyl derivatives of 13C-labeled fatty acids. Although IRMS is excellent for analyzing enrichment, it requires time-consuming derivatization steps and is not optimal for measuring FFA concentrations. We developed a new, rapid, and reliable method for simultaneous quantification of 13C-labeled fatty acids in plasma using high-performance liquid chromatography-mass spectrometry (HPLC/MS). This method involves a very quick Dole extraction procedure and direct injection of the samples on the HPLC system. After chromatographic separation, the samples are directed to the mass spectrometer for electrospray ionization (ESI) and analysis in the negative mode using single ion monitoring. By employing equipment with two columns connected parallel to a mass spectrometer, we can double the through-put to the mass spectrometer, reducing the analysis time per sample to 5 min. Palmitate flux measured using this approach agreed well with the GC/C/IRMS method.jlr This HPLC/MS method provides accurate and precise measures of FFA concentration and enrichment.

Original languageEnglish (US)
Pages (from-to)2761-2765
Number of pages5
JournalJournal of Lipid Research
Issue number9
StatePublished - Sep 2010


  • Flux
  • Liquid chromatography
  • Mass spectrometry
  • Palmitate

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Cell Biology


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