鱼肝油中脂肪酸的气相色谱及气相色谱-质谱分析

Determination of Fatty Acid Constituents in Cod Liver Oil by GC and GC-MS/MS

关键词:  鱼肝油  脂肪酸  甲酯化  气相色谱法  气相色谱-质谱联用法

Key words:  cod liver oil  fatty acid  methyl esterification  GC  GC-MS

摘要:

目的 采用气相色谱法（GC）结合气相色谱-质谱（GC-MS）联用技术，对3种不同来源共26批鱼肝油样品中的脂肪酸成分进行测定。方法 通过氢氧化钾-甲醇碱催化法对鱼肝油样品进行甲基衍生化预处理，选用极性毛细管柱对样品中的衍生化产物脂肪酸甲酯进行分离，后经气相色谱仪-氢火焰离子化检测器（GC-FID）和气相色谱-质谱（GC-MS）联用仪进行分析检测。利用对照品定位法结合NIST谱库检索准确鉴定出棕榈酸、棕榈油酸、油酸、亚油酸、二十碳五烯酸（eicosapentaenoic acid，EPA）和二十二碳六烯酸（docosahexaenoic acid，DHA）等14种脂肪酸，并通过面积归一化法对这14种脂肪酸进行定量分析。结果 这14种脂肪酸在国内鱼肝油中的含量与模拟天然鱼肝油和进口鱼肝油样品中的含量存在较大差异。其中，EPA和DHA等脂肪酸在模拟天然鱼肝油和进口鱼肝油样品中的含量远高于其在国内鱼肝油样品中的含量，而亚油酸在国内鱼肝油样品中的含量却高达44%以上，10倍于其在另外2种鱼肝油样品中的含量。结论 不同来源的鱼肝油样品中的脂肪酸成分不尽相同，可根据脂肪酸的组成区别鱼肝油样品中是否添加天然鱼肝油成分。

Abstract:

OBJECTIVE To analyze the fatty acid composition of 4 batches of imported cod liver oil samples, 6 batches of simulated natural cod liver oil samples and 16 batches of cod liver oil sampling from the domestic pharmaceutical market by gas chromatography(GC) and gas chromatography-mass spectrometry(GC-MS). METHODS The sample pretreatment was achieved through methyl esterification in the presence of KOH-MeOH, while the derived fatty acid methyl esters(FAMEs) were separated polar capillary column. The major fatty acid in cod liver oil were identified by located of the retention time of reference substance combined with NIST library searching of GC-MS. Palmitic acid, palmitoleic acid, oleic acid, linoleic acid, eicosapentaenoic acid(EPA), docosahexaenoic acid(DHA) and other 14 kinds of fatty acid were identified and quantitative analyzed by the normalization method of peak area. RESULTS The content of the identified 14 kinds of fatty acid in domestic pharmaceutical market cod liver oil samples showed a great difference with the imported cod liver oil and simulation of natural cod liver oil samples. Among them, the relative content of some fatty acid, especially, EPA and DHA in simulated natural cod liver oil and imported cod liver oil samples was much higher than that in the domestic cod liver oil samples. While the content of linoleic acid was as high as 44% in domestic cod liver oil samples, which was 10 times higher than it in the simulation of natural cod liver oil and imported cod liver oil samples. CONCLUSION The composition of fatty acid in cod liver oil samples vary from origin to origin. It suggests that whether the cod liver oil samples have add natural cod liver oil ingredients or not depending on the difference of fatty acid composition.