基于LC-MS/MS的咖啡酰奎宁酸异构体鉴别方法研究

该文对单咖啡酰奎宁酸和二咖啡酰奎宁酸的位置异构体分别进行液相色谱分析和不同碰撞能下的二级质谱分析,并对其质谱裂解规律进行了研究。结果发现,单咖啡酰奎宁酸的母离子377和子离子163在不同碰撞能下其强度发生显著变化,通过377/163的强度比值可区分其位置异构体。377/163比值大小依次为3-O-咖啡酰奎宁酸、4-O-咖啡酰奎宁酸、5-O-咖啡酰奎宁酸。二咖啡酰奎宁酸的母离子539和子离子377、163在不同碰撞能下其强度发生显著变化,通过539/377、377/163的强度比值可区分其位置异构体。539/377比值大小依次为4,5-O-二咖啡酰奎宁酸、3,4-O-二咖啡酰奎宁酸、3,5-O-二咖啡酰奎宁酸。377/163比值大小依次为3,5-O-二咖啡酰奎宁酸、4,5-O-二咖啡酰奎宁酸、3,4-O-二咖啡酰奎宁酸。基于Agilent Poroshell 120 SB-Aq C18色谱柱,不同梯度下咖啡酰奎宁酸位置异构体的洗脱顺序均为5-O-咖啡酰奎宁酸、4-O-咖啡酰奎宁酸、3-O-咖啡酰奎宁酸、3,4-O-二咖啡酰奎宁酸、3,5-O-二咖啡酰奎宁酸和4,5-O-二咖啡酰奎宁酸。通过色谱保留特征和质谱裂解规律对金银花中咖啡酰奎宁酸的位置异构体实现了准确鉴别。

Study on Identification Method for Caffeoylquinic Acids Isomers Based on Liquid Chromatography-Tandem Mass Spectrometry

In this paper,the positional isomers of monocaffeoylquinic acid and dicaffeoylquinic acid were separated and analyzed by liquid chromatography(LC),then analyzed by tandem mass spectrometry(MS/MS) with different collision energies.The fragmentation rules for the analytes were investigated using MS/MS.For the positional isomers of monocaffeoylquinic acid,as the intensities of their parent ion 377 and product ion 163 changed significantly under different collision energies,they could be distinguished by the intensity ratios of 377/163.The isomers with intensity ratios of 377/163 in turn were 3-O-caffeoylquinic acid,4-O-caffeoylquinic acid and 5-O-caffeoylquinic acid.As for the positional isomers of dicaffeoylquinic acid,the intensities of their parent ion 539 and product ions 377 and 163 changed significantly under different collision energies,they could be distinguished by their intensity ratios of 539/377 and 377/163.The isomers with intensity ratios of 539/377 in turn were 4,5-di-O-caffeoylquinic acid,3,4-di-O-caffeoylquinic acid and 3,5-di-O-caffeoylquinic acid,while the isomers with intensity ratios of 377/163 in order were 3,5-di-O-caffeoylquinic acid,4,5-di-O-caffeoylquinic acid and 3,4-di-O-caffeoylquinic acid.The positional isomers of caffeoquinic acid were separated and analyzed based on an Agilent Poroshell 120 SB-Aq C18 column,and the eluting orders were as follows:5-O-caffeoylquinic acid,4-O-caffeoylquinic acid,3-O-caffeoylquinic acid,3,4-di-O-caffeoylquinic acid,3,5-di-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid.The positional isomers of caffeoylquinic acid in honeysuckle were identified accurately based on the chromatographic retention and MS/MS characteristics.