Salanitro J P, Muirhead P A
Appl Microbiol. 1975 Mar;29(3):374-81. doi: 10.1128/am.29.3.374-381.1975.
A method for the preparation and gas chromatographic analysis of the butyl esters of volatile (C-1-C-7) and nonvolatile (lactic, succinic, and fumaric) acids in microbial fermentation media is presented. Butyl esters were prepared from the dry salts of the acids. The esters were separated by temperature programming on a column of Chromosorb W coated with Dexsil 300 GC liquid phase and analyzed with a flame ionization detector. Apparent recoveries with butanol-HCl or butanol-H2SO4 as butylating agents were 80 to 90% for most acids. Chromatographic profiles of the butyl esters demonstrated that both volatile and nonvolatile acids can be detected and separated in 24 min on a single column. Standard calibration curves (peak area versus concentration) of the butyl esters were linear in the range of 5 to 40 mumol of acid per ml. The advantages of using an internal standard (heptanoic acid) for quantitating fatty acids in a mixture are given. Chromatograms of butylated fermentation media in which rumen anaerobic bacteria were grown illustrated that this method is useful for determining short-chain volatile and nonvolatile acids of toxonomic significance.
本文介绍了一种用于制备和气相色谱分析微生物发酵培养基中挥发性（C-1-C-7）酸和非挥发性（乳酸、琥珀酸和富马酸）酸丁酯的方法。丁酯由酸的干燥盐制备而成。酯类通过程序升温在涂有Dexsil 300 GC液相的Chromosorb W柱上进行分离，并用火焰离子化检测器进行分析。以丁醇-HCl或丁醇-H2SO4作为丁基化剂时，大多数酸的表观回收率为80%至90%。丁酯的色谱图表明，挥发性和非挥发性酸均可在一根柱子上于24分钟内被检测和分离。丁酯的标准校准曲线（峰面积对浓度）在每毫升5至40微摩尔酸的范围内呈线性。文中给出了使用内标（庚酸）定量混合物中脂肪酸的优点。培养瘤胃厌氧细菌的丁基化发酵培养基的色谱图表明，该方法可用于测定具有分类学意义的短链挥发性和非挥发性酸。
