Li Xia, Liu Xu, Li Ling, Wang Yanli, Tian Qiyan, Liu Yanming
Shandong Institute for Food and Drug, Jinan 250000, China.
Shandong Environmental Law Enforcement Agency, Jinan 250000, China.
Se Pu. 2019 Feb 8;37(2):227-232. doi: 10.3724/SP.J.1123.2018.09024.
A method for the determination of propionic acid and its salts in food by gas chromatography (GC) was developed. Degrease extraction and direct extraction were established for food containing oil and non-oil, respectively. In this study, the effects of different pH values on the solubility and recovery of propionic acid were investigated. The effects of purification conditions, pH values, extraction agent types, and extraction times were studied. After hydrochloric acid solution was added, the pH levels of sample solutions were all found to be less than 2. The sample solutions were degreased with 5 mL -hexane and extracted twice with 5 mL ethyl acetate. The analytes were detected by GC. The analytes were separated on an HP-INNOWAX chromatographic column and detected by fame ionization detector (FID). The recoveries of degrease extraction were 87.5%-97.6% and relative standard deviation were 3.09%-6.86% (=6). The recoveries of direct extraction were 90.1%-102.1% and the relative standard deviations were 3.32%-6.33% (=6). The two methods showed good linearities in the range of 2-1000 mg/L (correlation coefficient is 0.9998). The limit of detection was 0.003 g/kg and the limit of quantification was 0.01 g/kg. The proposed method is accurate, fast, simple, easy, sensitive, and is suitable for the rapid determination of propionic acid and its salts in different food. The proposed method provides a new way for the determination of propionic acid in food.
建立了一种气相色谱法（GC）测定食品中丙酸及其盐类的方法。分别针对含油食品和无油食品建立了脱脂萃取法和直接萃取法。本研究考察了不同pH值对丙酸溶解度和回收率的影响。研究了净化条件、pH值、萃取剂类型和萃取次数的影响。加入盐酸溶液后，发现样品溶液的pH值均小于2。样品溶液用5 mL正己烷脱脂，并用5 mL乙酸乙酯萃取两次。通过气相色谱法检测分析物。分析物在HP-INNOWAX色谱柱上分离，并用火焰离子化检测器（FID）检测。脱脂萃取法的回收率为87.5%-97.6%，相对标准偏差为3.09%-6.86%（n=6）。直接萃取法的回收率为90.1%-102.1%，相对标准偏差为3.32%-6.33%（n=6）。两种方法在2-1000 mg/L范围内均表现出良好的线性关系（相关系数为0.9998）。检测限为0.003 g/kg，定量限为0.01 g/kg。该方法准确、快速、简便、灵敏，适用于不同食品中丙酸及其盐类的快速测定。该方法为食品中丙酸的测定提供了一种新途径。
