BackgroundIn order to quantitatively measure short chain fatty acids (SCFAs) in microbial samples, sample preparation and analytical conditions using gas chromatography with flame ionization detection (GC-FID) were established.MethodsThe extraction of SCFAs with ethyl ether-hexane (1:1, v/v) followed by the aminopropyl solid phase extraction (SPE) was carried out. An acid-modified poly(ethylene glycol) GC column was used for the chromatographic separation of four volatile fatty acids.ResultsGood linearity was obtained with r > 0.999 in the calibration range. The limits of quantification (LOQs) of the analytical method were in the ranges of 5.71 to 11.20 μg/mL. The overall recoveries excluding acetic acid ranged between 96.51 and 108.83% with relative standard deviations (RSD) below 10% for the entire procedure from the results of matrix spiking experiments at three concentration levels.ConclusionThe analytical method was validated in accordance with the requirements of the international guideline. The method enables the use of the most commonly used technology without derivatization and the elimination of interferences in the sample matrix.

中文翻译：

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固相萃取和气相色谱火焰离子化检测法定量测定微生物样品中短链脂肪酸的方法开发

背景为了定量测定微生物样品中的短链脂肪酸（SCFAs），建立了使用气相色谱-火焰离子化检测器（GC-FID）的样品制备和分析条件。方法用乙醚-己烷（1:1， v/v)，然后进行氨丙基固相萃取 (SPE)。采用酸改性聚乙二醇气相色谱柱对四种挥发性脂肪酸进行色谱分离。结果线性良好，r > 0.999 在校准范围内。分析方法的定量限 (LOQ) 范围为 5.71 至 11.20 μg/mL。不包括乙酸的总回收率介于 96.51 和 108 之间。83%，整个程序的相对标准偏差 (RSD) 在三个浓度水平的基质加标实验结果中低于 10%。结论该分析方法按照国际指南的要求进行了验证。该方法可以使用最常用的技术，无需衍生化并消除样品基质中的干扰。