Cren-Olivé C, Déprez S, Lebrun S, Coddeville B, Rolando C
Université des Sciences et Technologies de Lille, UPRESA 8009, Chimie Organique et Macromoléculaire, Equipe Polyphénols, B atiment C4, 59655 Villeneuve d'Ascq, France.
Rapid Commun Mass Spectrom. 2000;14(23):2312-9. doi: 10.1002/1097-0231(20001215)14:23<2312::AID-RCM160>3.0.CO;2-A.
Liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was used for the structural characterization and differentiation of four isomeric O-monomethylated catechins (on phenolic positions) by the analysis of the fragmentation behaviour of catechin. The catechin fragmentation routes were rationalized and it is shown that several diagnostic ions such as (1,3)A(+), (1,2)B(+), and (1,4)B(+) allow the unambiguous identification of the methylated ring. The precise position of the methyl group on each ring is determined by the difference in the relative intensities of the diagnostic ions. Isomeric O-methylepicatechins were also differentiated using this methodology.
采用液相色谱/电喷雾电离串联质谱法（LC/ESI-MS/MS），通过分析儿茶素的碎片行为，对四种（酚羟基位置）异构的O-单甲基化儿茶素进行结构表征和区分。儿茶素的碎片途径得到了合理的解释，结果表明，一些诊断离子，如(1,3)A(+)、(1,2)B(+)和(1,4)B(+)，能够明确鉴定甲基化环。每个环上甲基的精确位置由诊断离子相对强度的差异来确定。也使用该方法区分了异构的O-甲基表儿茶素。
