A rapid and convenient derivatization method for quantitation of short-chain fatty acids in human feces by ultra-performance liquid chromatography/tandem mass spectrometry

Rapid Commun Mass Spectrom. 2020 May 15;34(9):e8730. doi: 10.1002/rcm.8730.

Abstract

Rationale: Short-chain fatty acids (SCFAs) are associated with intestinal microbiota and diseases in humans. SCFAs have a low response in mass spectrometry, and in order to increase sensitivity, reduce sample consumption, shorten analysis time, and simplify sample preparation steps, a derivatization method was developed.

Methods: We converted seven SCFAs into amide derivatives with 4-aminomethylquinoline. The reaction occurred for 20 min at room temperature. The analytes were separated on a reversed-phase C18 column and quantitated in the positive ion electrospray ionization mode using multiple reaction monitoring. Acetic acid-d4 was used as the stable-isotope-labeled surrogate analyte for acetic acid in the working solutions, while the other stable-isotope-labeled standards were used as internal standards (ISs).

Results: Method validation showed that the intra-day and inter-day precision of quantitation for the seven SCFAs over the whole concentration range was ≤3.8% (n = 6). The quantitation accuracy ranged from 85.5% to 104.3% (n = 6). Most important, the collected feces were vortexed immediately with ethanol.

Conclusions: This study provides a new derivatization method for a precise, accurate, and rapid quantitation of SCFAs in human feces using ultra-performance liquid chromatography/tandem mass spectrometry. This method successfully determined the concentration of SCFAs in human feces and could assist in the exploration of intestinal microbiota and diseases.

MeSH terms

  • Chromatography, High Pressure Liquid / economics
  • Chromatography, High Pressure Liquid / methods
  • Fatty Acids, Volatile / analysis*
  • Feces / chemistry*
  • Feces / microbiology
  • Gastrointestinal Microbiome
  • Humans
  • Tandem Mass Spectrometry / economics
  • Tandem Mass Spectrometry / methods*
  • Time Factors

Substances

  • Fatty Acids, Volatile