气相色谱法测定牛乳脂肪酸前处理方法的优化

Optimization of pretreatment method for fatty acids in bovine milk by gas chromatography

优化气相色谱法测定牛乳脂肪酸时甲酯化处理方法的条件。利用氨水-乙醇法提取牛乳中脂肪,通过不同条件下各因素试验和响应面分析,使脂肪酸甲酯化的参数最佳,测定甲酯化前后脂肪酸酸值,计算甲酯化率。经回归分析确定脂肪酸甲酯化的最优条件为:反应时间为23.05 min,反应温度为84.24℃,KOH-甲醇的添加量为2.23 mL,三氟化硼-甲醇添加量为1.13 mL,在此条件下牛乳脂肪酸甲酯化率达到99.2%。比未优化前脂肪酸甲酯化率明显提高,且节省样品和试剂,对牛乳脂肪酸准确定性定量分析具有重要意义。

In an effort to optimize the reaction conditions of methyl ester of fatty acid in bovine milk detected by gas chromatography, milk fatty was extracted by ammonia-ethanol method, single factor experiment and response surface analysis was used to optimize the process of fatty acid methyl. Acid values of fatty acids were determined, and the ratio of fatty acid methyl ester then was calculated. The result of response surface analysis showed that the optimum conditions of fatty acid methyl were： a reaction time of 23.05 min, temperature was 84.24 ~C, the additive of KOH-methyl alcohol was 2.23 mL, and boron trifiuoride-methyl alcohol of 1.13 mL. Using these optimal factor values under experimental conditions, bovine milk fatty acid methyl ester of 99.20% was achieved, fatty acid methyl estedficate rate was increased distinctly after adopted to optimal conditions, samples and reagents were saved, which was significant for accurate qualitative and quantitative analysis of fatty acids.