气相色谱法同时测定保健食品中的5种不饱和脂肪酸

Determination of 5 kinds of polyunsaturated fatty acids in dietary supplements by gas chromatography

目的建立气相色谱法同时测定保健食品中亚油酸、α-亚麻酸、二十碳五烯酸（eicosapentaenoic acid,EPA）、二十二碳六烯酸（docosahexaenoic acid,DHA）和二十二碳五烯酸（docosapentaenoic acid,DPA）的含量。方法样品先采用氢氧化钾甲醇溶液进行皂化处理,再用三氟化硼甲醇溶液甲酯化,经HP-FFAP色谱柱（30m×0.53 mm,1.0μm）分离测定。结果 EPA甲酯、DHA甲酯、DPA甲酯、亚油酸甲酯、α-亚麻酸甲酯分别在0.03927~1.178、0.04200~1.260、0.03449~1.035、0.08368~1.255、0.08482~4.241 mg/mL的浓度范围内线性关系良好,相关系数r均大于0.999;检出限分别为0.0039、0.0042、0.0034、0.0042、0.0042 mg/mL;加标回收率在91.1%~109.3%之间,相对标准偏差均小于5%。结论该方法操作简单快捷,适用于保健食品中亚油酸、α-亚麻酸、EPA、DPA和DHA的测定。

Objective To establish a method for the determination of linoleic acid,alpha-linolenicacid,eicosapentaenoic acid（EPA）,docosahexaenoic acid（DHA）,and docosapentaenoic acid（DPA） in dietary supplements by gas chromatography.Methods The samples were treated by KOH-methanol solution,and methyl esterified using boron trifluoride-methanol complex.Linoleic acid,alpha-linolenic acid,EPA,DHA,and DPA in dietary supplements were separated and detected by HP-FFAP（30 m×0.53 mm,1.0 μm） column.Results This method showed a good linearity in the range of 0.03927~1.178 mg/mL for methyl EPA,0.04200~1.260 mg/mL for methyl DHA,0.03449~1.035 mg/mL for methyl DPA,0.08368~1.255 mg/mL for methyllinoleic acid,and 0.08482~4.241 mg/mL for methylalpha-linolenic acid with the correlation coefficients higher than 0.999.The limit of detection of methyllinoleic acid,methylalpha-linolenic acid,methyl EPA,methyl DPA and methyl DHA were 0.0042 mg/mL,0.0042 mg/mL,0.0039 mg/mL,0.0034 mg/mL,and 0.0042mg/mL,respectively,with recovery rates of 91.1%~109.3%and RSD less than 5%.Conclusion This method is simple and rapid,and can be used to determine the content of linoleic acid,alpha-linolenic acid,EPA,DPA,and DHA in dietary supplements.