毛细管气相色谱法同时检测分析鱼油中十八碳三烯酸、二十碳五烯酸和二十二碳六烯酸

Simultaneous determination of α-calendic acid,eicosapentaenoic acid and docosahexenoic acid in fish oil by capillary gas chromatography

目的建立毛细管气相色谱法同时测定鱼油中十八碳三烯酸(α-LNA)、二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量的方法。方法样品经氢氧化钾-甲醇溶液直接甲酯化后用极性色谱柱分离,气相色谱分析,外标法定量。结果鱼油中α-LNA、EPA和DHA均获得到良好的分离,3种被测组分的峰面积与其质量浓度之间有良好的线性关系(相关系数均>0.999),方法检出限分别为2.7 mg/L、4.6 mg/L和4.2 mg/L;样品加标回收率为92.6%~101.2%,相对标准偏差为1.2%~3.9%。应用该法对市售的10批次鱼油样品进行检测,大部分样品被检测物含量均在其产品的标示量范围内。结论该方法前处理简单,分析时间短,选择性好,灵敏度高,适用于鱼油中α-LNA、EPA和DHA含量的检测。

Objective To establish a capillary gas chromatography method for the simultaneous determination of α-calendic acid（ α-LNA）,eicosapentaenoic acid（ EPA） and docosahexenoic acid（ DHA） in fish oil.Methods The samples were methylated with KOH-CH3 OH,separated by polar capillary column,detected by gas chromatography and then quantified with external standard method.Results α-calendic acid,EPA and DHA in fish oil were separated from each other.There were good linear relationaships between their concentration and their peak area,and the correlation coefficient（ r） was more than 0.999.The detection limits of the method were 2.7 mg/L,4.6 mg/L and 4.2 mg/L,respectively.The average spiked recoveries were within 92.6%-101.2%,and the relative standard deviations were within 1.2%-3.9%.10 batches of commercial available fish oil were determined with this method.The results showed that the contents of most samples were within the labelled amount.Conclusion The method is simple,quick,sensitive and effective,and it is suitable for the determination of α-LNA,EPA and DHA in fish oil.