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目的全面分析牡丹籽油的脂肪酸组成,为牡丹籽油的保真和掺伪鉴别提供基础。方法采用氢氧化钾甲醇溶液对牡丹籽油中的脂肪酸甲酯化得到脂肪酸甲酯,采用DB-23毛细管柱对脂肪酸甲酯进行分离,利用质谱选择离子扫描的方式进行检测分析。根据脂肪酸甲酯的质谱特征确定脂肪酸的类型,并识别出样品中的直链饱和脂肪酸甲酯,利用样品中的直链饱和脂肪酸甲酯的保留时间计算其它脂肪酸甲酯的等效链长,然后与相同或相近色谱条件下测定标准品的等效链长比较确定其它脂肪酸甲酯的结构,并利用其质谱特征进行验证。结果本方法可以在不使用标准品的情况下鉴定出牡丹籽油中27种脂肪酸。结论本法测定的牡丹籽油脂肪酸数据明显多于现有方法,为全面认识牡丹籽油的脂肪酸组成并将之应用于保真和掺伪鉴别提供基础。
Objective To comprehensively analyze the fatty acid composition of peony seed oil and provide the basis for fidelity and identification of peony seed oil. Methods Methyl fatty acid methyl ester was obtained from methyl peony seed oil by methanolic potassium hydroxide solution. The fatty acid methyl ester was separated by DB-23 capillary column and detected by mass spectrometry selective ion scan. The type of fatty acid is determined based on the mass spectral characteristics of fatty acid methyl esters and the linear saturated fatty acid methyl esters in the sample are identified. The equivalent chain length of the other fatty acid methyl esters is calculated using the retention time of the straight chain saturated fatty acid methyl esters in the sample. The structure of the other fatty acid methyl esters was confirmed by comparison with the equivalent chain lengths of the standard samples under the same or similar chromatographic conditions. Results This method allows the identification of 27 fatty acids in peony seed oil without the use of standard ingredients. Conclusion The data of peony seed oil determined by this method are obviously more than those of the existing methods. It provides the basis for understanding the fatty acid composition of peony seed oil and applying it to fidelity and adulteration identification.