Abstract：
Short-chain fatty acids (SCFAs) are organic acids with carbon atoms less than six, released through fermentation products by intestinal microbiome, having multiple physiological activities. Considering weak acidity and high volatility, derivatization or liquid-liquid extraction is essential, which is time consuming. Headspace-solid-phase dynamic extraction (HS-SPDE) coupled with gas chromatography-mass spectrometry is automated and effortless to determine SCFAs in rat feces. The extraction procedure is performed by aspirating and discharging the headspace cyclically through a steel needle, coated with an inner polyethylene glycol sorbent. The key parameters of SPDE were optimized including coating type, incubation time and temperature, and number of extraction strokes. Besides, salting-out was conducted. Then, a method by HS-SPDE-GC-MS was established and validated. It only took 3-min incubation time, 4.5 min extraction time, and 13 min chromatographic separation in a run. The recovery, linearity, limit of quantification, and stability were evaluated. Then, the proposed method was applied to analyze rat feces including 18 rats with liver injury and 23 normal controls. Mann-Whitney U test indicated that the concentrations of six SCFAs in normal rat feces were higher than those with liver injury. This method provides a choice for fast, solvent-free, automated, and high-throughput analysis of SCFAs.
摘要：
短链脂肪酸（SCFA）是碳原子数少于6的有机酸，通过肠道微生物组通过发酵产物释放，具有多种生理活动。考虑到弱酸性和高挥发性，衍生化或液液萃取是必不可少的，这是耗时的。顶空-固相动态萃取（HS-SPDE）与气相色谱-质谱联用是自动且毫不费力地确定大鼠粪便中的SCFA。提取过程是通过钢针循环抽吸和排出顶部空间来进行的，涂有内部聚乙二醇吸附剂。优化了SPDE的关键参数，包括涂层类型，孵育时间和温度，和提取笔划的数量。此外,进行了盐析。然后，建立并验证了HS-SPDE-GC-MS方法。只花了3分钟的孵化时间,4.5min提取时间,和13分钟的色谱分离运行。复苏,线性度定量极限，并对稳定性进行了评价。然后，该方法用于分析大鼠粪便，包括18只肝损伤大鼠和23只正常对照。Mann-WhitneyU检验表明，正常大鼠粪便中6种SCFA的浓度高于肝损伤大鼠。此方法为快速，无溶剂,自动化,和SCFA的高通量分析。
