Rapid measurement of 13C-enrichment of acetic, propionic and butyric acids in plasma with solid phase microextraction coupled to gas chromatography–mass spectrometry Original Research Article

An analytical procedure based on solid phase microextraction (SPME) has been developed to quantify [1-13C]-labelled short-chain fatty acids (SCFAs)—mainly acetic, propionic and butyric acids—in a small volume (120 μl) of deproteinised plasma (corresponding to 200 μl of raw plasma) by gas chromatography–mass spectrometry (GC–MS) analysis. Simultaneous SCFA extraction was optimal after 5 min using a 75 μm Carboxen/polydimethylsiloxane-coated fiber. The base peak of the three analytes has been characterised by middle-resolution mass spectrometry (R>6000). All these data allowed the specificity reinforcement of the measure.