Short chain fatty acids (SCFA) and ketone bodies recently emerged as important physiological relevant metabolites because of their association with microbiota, immunology, obesity and other metabolic states. They were commonly analyzed by GC–MS with long run time and laborious sample preparation. In this study we developed a novel LC-MS/MS method using fast derivatization coupled with liquid-liquid extraction to detect SCFA and ketone bodies in plasma and feces. Several different derivatization reagents were evaluated to compare the efficiency, the sensitivity and chromatographic separation of structural isomers. O‑benzylhydroxylamine was selected for its superior overall performance in reaction time and isomeric separation that allowed the measurement of each SCFAs and ketone bodies free from interferences. The derivatization procedure is facile and reproducible in aqueous-organic medium, which abolished the evaporation procedure hampering the analysis of volatile short chain acids. Enhancement in sensitivity remarkably improved the detection limit of SCFA and ketone bodies to sub-fmol level. This novel method was applied to quantify these metabolites in fecal and plasma samples from lean and DIO mouse.

短链脂肪酸（SCFA）和酮体由于与微生物群，免疫学，肥胖症和其他代谢状态相关，最近已成为重要的生理相关代谢产物。通常使用GC-MS对它们进行分析，需要较长的运行时间和费力的样品前处理。在这项研究中，我们开发了一种新颖的LC-MS / MS方法，该方法使用快速衍生化结合液-液萃取来检测血浆和粪便中的SCFA和酮体。对几种不同的衍生试剂进行了评估，以比较结构异构体的效率，灵敏度和色谱分离。选择O-苄基羟胺的原因是它在反应时间和异构体分离方面具有优异的整体性能，从而使每个SCFA和酮体的测量均不受干扰。衍生化过程在水性有机介质中很容易且可重现，从而取消了蒸发过程，从而不利于挥发性短链酸的分析。灵敏度的提高显着地将SCFA和酮体的检出限提高至亚fmol水平。这种新颖的方法被应用于量化瘦肉和DIO小鼠粪便和血浆样品中的这些代谢产物。