Comparison of CID versus ETD-based MS/MS fragmentation for the analysis of doubly derivatized steroids
作者:Yu-Min Juang、Tzu-Fang She、Hui-Yi Chen、Chien-Chen Lai
DOI:10.1002/jms.3300
日期:2013.12
Electrospray ionization coupled with collision-induced dissociation (CID) and tandem mass spectrometry (MS/MS) is a commonly used technique to analyze the chemical composition of steroids. However, steroids are structurally similar compounds, making it difficult to interpret their product-ion spectra. Electron transfer dissociation (ETD), a relatively new technique for protein and peptide fragmentation, has been shown to provide more detailed structural information. In this study, we compared the ability of CID with that of ETD to differentiate between eight 3,20-dioxosteroids that had been derivatizated with a quaternary ammonium salt, Girard reagent P (GirP), at room temperature or after exposure to microwave irradiation to generate doubly charged ions. We found that the derivatization of steroid with GirP hydrazine occurred in less than 10 min when the reaction was carried out in the presence of microwave irradiation compared to 30 min when the reaction was carried out at room temperature. According to the MS/MS spectra, CID provided rich, structurally informative ions; however, the spectra were complex, thereby complicating the peak assignment. In contrast, ETD generated simpler spectra, making it easier to recognize individual peaks. Remarkably, both CID and ETD were allowed to differentiate of steroid isomers, 17α-hydroxyprogesterone (17OHP) and deoxycorticosterone (DOC), but the signature ions obtained from CID were less intense than those generated by ETD, which generated much clearer spectra. These results indicate that ETD in conjunction with CID can provide more structural information for precise characterization of steroids. Copyright © 2013 John Wiley & Sons, Ltd.
电喷雾电离结合碰撞诱导解离(CID)和串联质谱(MS/MS)是一种常用的分析类固醇化学成分的技术。然而,类固醇是结构相似的化合物,这使得其产物离子谱的解释变得困难。电子转移解离(ETD)是一种相对较新的蛋白质和肽的裂解技术,已显示出能够提供更详细的结构信息。在本研究中,我们比较了CID与ETD区分八种在常温或经微波辐射处理以生成双带电离子的3,20-二氧类固醇,与四级铵盐Girard试剂P(GirP)衍生化的能力。我们发现,当反应在微波辐射下进行时,类固醇与GirP肼的衍生化在不到10分钟内完成,而在常温下进行时则需要30分钟。根据MS/MS谱图,CID提供了丰富的、具有结构信息的离子;然而,谱图复杂,这使得峰的分配变得困难。相反,ETD生成了更简单的谱图,使得识别单个峰变得更加容易。值得注意的是,CID和ETD均能够区分类固醇异构体17α-羟孕酮(17OHP)和脱氧皮质醇(DOC),但来自CID的特征离子强度低于ETD生成的离子,后者生成了更清晰的谱图。这些结果表明,ETD与CID结合能够为类固醇的精确表征提供更多的结构信息。版权 © 2013 John Wiley & Sons, Ltd.