Application of 2-Picolylamine Derivatized Ultra-high Performance Liquid Chromatography Tandem Mass Spectrometry for the Determination of Short-chain Fatty Acids in Feces Samples

We present a sensitive and selective method for the simultaneous determination of short-chain fatty acids (SCFAs), such as acetic acid (AA), propionic acid, butyric acid (BA), isobutyric acid, valeric acid, isovaleric acid, hydroangelic acid, caproic acid, 4-methylvaleric acid and succinic acid (SA) in feces samples using a ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) with simple derivatization of 2-picolylamine. The main SFCAs were derivatized in the same condition, and showed the specific product ion (m/z 109) in the electrospray positive mode regarding to 2-picolylamine. The derivatized SA showed a different pattern of the product ion (m/z 191). The derivatized analytes showed LOD < 75 nM, LOQ < 100 nM and r(2) in the calibration curve > 0.991. The QuEChERS was used for sample preparation of feces samples. In the recovery test, the recovery values appeared from 89.7 to 100.2% (RSD: 2.1 to 9.2%, n = 6). This developed method was applied to evaluate obese diabetes model mice. In the result, the branched-chain SCFAs levels in feces from model mice of spontaneous obese type II diabetes were on a declining trend compared with normal. The AA levels from model mice with high-calorie/fat diet are owed a declining trend for 3 to 9 months. The BA levels showed that normal mice were increasing, and model mice had decreased tendency for breeding months. High-calorie/fat diet showed that the SA levels increased.