建立了PEG-20M固定液毛细管柱气相色谱法直接测定合成气厌氧发酵液中挥发性脂肪酸（VFAs，乙醇、乙酸、丙酸、丁酸、戊酸、己酸和辛酸）的方法;在对样品预酸化处理（pH=3）后，对比程序升温和恒温两种色谱条件对VFAs的分离时间，并确定了恒温条件下方法的线性范围、检出限、精密度及回收率;结果表明:在恒温条件下，分离C6以内（乙醇、乙酸、丙酸、丁酸、戊酸和己酸）VFAs的总时长在5 min左右，仅辛酸出峰时间在9.8 min；全部7种化合物所在线性范围内，相关系数r均大于0.9937，线性良好；检出限在0.4~1.1 mg/L之间；实际样品不同质量浓度的加标回收，其回收率在94.5%~109.3%之间，相对标准偏差小于10.4%。
The Gas Chromatography has been applied to the direct determination of volatile fattyacids (VFAs, ethanol, acetic acid, propionic acid, butyric acid, pentanoic acid, caproic acid and octanoic acid) in the anaerobic fermentation liquid of synthesis gas. Two gas chromatographic conditions of order temperature hoist and constant temperature were investigated, followed by acidification of the sample（pH=3）and GC analysis，with PEG-20M stationary liquid capillary column and flame ionization detector（FID）. The optimum conditions（constant temperature）including the detection limits, precisions and recoveries have been analyzed. The results show that under constant temperature,the total time for separating VFAs including ethanol,acetic acid,propionic acid,butyric acid,pentanoic acid and caproic acid is about 5 minutes but the time for separating octanoic acid is 9.8 minutes.The linear range of VFAs were good linearity with the correlation coefficients r≥0.993 7, the detection limits were in range of 0.4—1.1mg/L. The recoveries of the actual sample with different concentrations were between 94.5—109.3% and the relative standard deviations were less than 10.4%.
DAI Chen-wei, WANG Hua-jie, WU Ming-hua. The Gas Chromatographic Determination of Volatile Fatty Acids in the Anaerobic Fermentation Liquid of Synthesis Gas[J]. Journal of Chongqing Technology and Business University(Natural Science Edition）,2019,36(3):111-115