da Costa C T, Dalluge J J, Welch M J, Coxon B, Margolis S A, Horton D
American University, Department of Chemistry, 4400 Massachusetts Avenue, Washington, DC 20016, USA.
J Mass Spectrom. 2000 Apr;35(4):540-9. doi: 10.1002/(SICI)1096-9888(200004)35:4<540::AID-JMS966>3.0.CO;2-Y.
Reversed-phase liquid chromatography with atmospheric pressure chemical ionization mass spectrometry (LC/APCI-MS) in the positive-ion mode was utilized to analyze crude ether extracts from the root bark of Maclura pomifera, a tree known to have a high content of prenylated xanthones and flavanones. Identification of three xanthones and two flavanones was based on their unique mass spectra. Under optimum conditions peaks corresponding to the MH ion and characteristic fragments for each compound were observed. (1)H NMR data were used to confirm the identities of two xanthones that had the same molecular mass and similar fragmentation patterns. Fragmentation of the analytes was achieved by application of an electrostatic potential at the entrance of the single quadrupole mass spectrometer. The optimum voltage for fragmentation was found to be related to the class of compounds analyzed and, within each class, to be dependent on the structure of the prenyl moiety. Collision-induced pathways consistent with precedent literature describing the MS characterization of similar compounds and with the observed fragmentation patterns are tentatively proposed.
采用正离子模式的反相液相色谱-大气压化学电离质谱联用技术（LC/APCI-MS）对桑橙树根皮的粗乙醚提取物进行分析，桑橙树富含异戊烯基黄酮和黄烷酮。基于三种黄酮和两种黄烷酮独特的质谱图对其进行鉴定。在最佳条件下，观察到了对应于各化合物的MH离子峰和特征碎片峰。利用(1)H NMR数据确认了两种分子量相同且碎裂模式相似的黄酮的结构。通过在单四极杆质谱仪入口处施加静电势实现分析物的碎裂。发现碎裂的最佳电压与所分析化合物的类别有关，并且在每一类化合物中，还取决于异戊烯基部分的结构。初步提出了与先前描述类似化合物质谱表征的文献以及观察到的碎裂模式一致的碰撞诱导途径。
