Saturated fatty acid determination method using paired ion electrospray ionization mass spectrometry coupled with capillary electrophoresis

Ji Hyun Lee, Su Jin Kim, Sul Lee, Jin Kyu Rhee, Soo Young Lee, Yun Cheol Na

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


A sensitive and selective capillary electrophoresis-mass spectrometry (CE-MS) method for determination of saturated fatty acids (FAs) was developed by using dicationic ion-pairing reagents forming singly charged complexes with anionic FAs. For negative ESI detection, 21 anionic FAs at pH 10 were separated using ammonium formate buffer containing 40% acetonitrile modifier in normal polarity mode in CE by optimizing various parameters. This method showed good separation efficiency, but the sensitivity of the method to short-chain fatty acids was quite low, causing acetic and propionic acids to be undetectable even at 100 mgL−1 in negative ESI-MS detection. Out of the four dicationic ion-pairing reagents tested, N,N’-dibutyl 1,1’-pentylenedipyrrolidium infused through a sheath-liquid ion source during CE separation was the best reagent regarding improved sensitivity and favorably complexed with anionic FAs for detection in positive ion ESI-MS. The monovalent complex showed improved ionization efficiency, providing the limits of detection (LODs) for 15 FAs ranging from 0.13 to 2.88 μg/mL and good linearity (R2 > 0.99) up to 150 μg/mL. Compared to the negative detection results, the effect was remarkable for the detection of short- and medium-chain fatty acids. The optimized CE-paired ion electrospray (PIESI)-MS method was utilized for the determination of FAs in cheese and coffee with simple pretreatment. This method may be extended for sensitive analysis of unsaturated fatty acids.

Original languageEnglish
Pages (from-to)223-231
Number of pages9
JournalAnalytica Chimica Acta
StatePublished - 1 Sep 2017

Bibliographical note

Funding Information:
This work was supported by the National Research Council of Science and Technology through the Degree & Research Center program ( DRC-14-1-KBSI ). Appendix A

Publisher Copyright:
© 2017 Elsevier B.V.


  • Capillary electrophoresis-mass spectrometry (CE-MS)
  • Ion paring reagent
  • Paired ion electrospray ionization (PIESI)
  • Saturated fatty acid


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