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

<jats:sec><jats:title>Rationale</jats:title><jats:p>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.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>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‐d<jats:sub>4</jats:sub> 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).</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>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% (<jats:italic>n</jats:italic> = 6). The quantitation accuracy ranged from 85.5% to 104.3% (<jats:italic>n</jats:italic> = 6). Most important, the collected feces were vortexed immediately with ethanol.</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>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.</jats:p></jats:sec>