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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 method for simultaneous determination of α-LNA, EPA and DHA in fish oil by capillary gas chromatography. Methods The samples were directly methylated by potassium hydroxide-methanol solution and separated by polar column. Gas chromatographic analysis and external standard method were used for quantification. Results The results showed that α-LNA, EPA and DHA in fish oil were well separated. The peak areas of the three tested components were in good linear relationship with their mass concentrations (correlation coefficient> 0.999). The detection limits were 2.7 mg / L, 4.6 mg / L and 4.2 mg / L. The recoveries of spiked samples ranged from 92.6% to 101.2% with relative standard deviations of 1.2% -3.9%. This method is used to test 10 batches of fish oil samples sold on the market, most of the samples were detected in the amount of content in the range of the labeled amount of their products. Conclusion The method is simple, short time, high selectivity and high sensitivity. It is suitable for the detection of α-LNA, EPA and DHA in fish oil.