Profiling of non-esterified fatty acids in human plasma using liquid chromatography-electron ionization mass spectrometry

• Published in: Analytical and bioanalytical chemistry Vol. 400; no. 9; pp. 2933 - 2941
• Main Authors: Trufelli, Helga, Famiglini, Giorgio, Termopoli, Veronica, Cappiello, Achille
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.07.2011; Springer
• Subjects: Adult; Adults; Analysis; Analytical Chemistry; Biochemistry; Calibration; Characterization and Evaluation of Materials; Chemical properties; Chemistry; Chemistry and Materials Science; Chromatographic methods and physical methods associated with chromatography; Chromatography, Liquid - methods; Diabetes Mellitus - blood; Equipment Design; Exact sciences and technology; Fatty acids; Fatty Acids, Nonesterified - blood; Food Science; Gas chromatographic methods; Human; Humans; Ionization; Laboratory Medicine; Linearity; Liquid chromatography; Mass spectrometry; Monitoring/Environmental Analysis; Original Paper; Other chromatographic methods; Profiling; Spectrometric and optical methods; Spectrometry, Mass, Electrospray Ionization - instrumentation; Spectrometry, Mass, Electrospray Ionization - methods; Spectrum analysis; LC-Direct-EI-MS; Non-esterified fatty acids; Human plasma; Diabetes; Plasma; Chemical analysis; Electron impact ionization; Identification; Derivatization; Electrospray; Chemical enrichment; Target; Sample preparation; Detection limit; Quality; Adult; Time analysis; Quantitative analysis; Human; Liquid liquid extraction; Coupled method; Sample; Liquid chromatography; Matrix effect; Calibration; Fatty acids; Chemical ionization; Gas chromatography; Reversed phase chromatography; Linearity; Library; Mass spectrometry; Electron spectrometry
• ISSN: 1618-2642; 1618-2650; 1618-2650
• DOI: 10.1007/s00216-011-4955-x

This paper focuses on the development of a novel approach to analyze underivatized fatty acids in human plasma. The method is based on liquid–liquid extraction followed by reversed phase liquid chromatography coupled to direct-electron ionization mass spectrometry (LC-Direct-EI-MS). The assay is validated. Calibrations show satisfactory linearity and precision in the investigated range of linearity. Recoveries span from 75% to 104%. The method limits of detection, varying from 0.53 to 5.35 μM, are satisfactory for the quantitation of non-esterified fatty acids (NEFAs) in plasma at physiological levels. The method has been successfully applied to the NEFAs profiling of plasma samples from healthy adult volunteers and subjects affected by diabetes mellitus. Compared with published protocols based on gas chromatography–mass spectrometry and liquid chromatography coupled to electrospray ionization mass spectrometry, this method does not require derivatization and does not show matrix effects, thus simplifying sample preparation procedure and reducing the total time of analysis to approximately 90 min. In addition, Direct-EI-MS allows the acquisition of high-quality NIST library-matchable EI spectra, allowing an easy-to-obtain identification of the target NEFAs.