质谱特征结合等效链长用于牡丹籽油 脂肪酸组成分析

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。

Analysis of fatty acid composition of peony seed oil using mass spectral characteristics and equivalent chain length

Objective To fully analyze the fatty acid composition of peony seed oil for subsequent potential adulteration detection. Methods Fatty acids in peony seed oil were derived and analyzed by gas chroma-tography-mass spectrometry(GC-MS) in selected ion monitoring mode (SIM). Subsequently, structure identification of FAMEs in the peony seed oil was conducted by comparing their mass spectral characteristics and equivalent chain length (ECL) values with those of the fatty acids in Chrombox. The mass spectral characteristics were used to determine the kinds of FAMEs. The ECLs were calculated and used to infer the structure of FAMEs. Finally, fatty acids in peony seed oils were identified and partially validated by reference standards. Results Fatty acids in peony seed oil were identified and partially validated by reference standards. The results showed that 27 fatty acids were identified in peony seed oil. Conclusion The identification method based on the combination of ECL and MS could identify more fatty acids than the existing methods without using reference standards and might benefit the subsequent potential adulteration detection of peony seed oil.