N2-DART-Orbitrap中的特征气相离子反应及在西药快速检测中的应用

摘要

采用实时直接分析(DART)离子源串联高分辨质谱Orbitrap技术(DART-Orbitrap MS),对8种市售常见西药进行有效成分分析,建立了一种快速、简便、准确测定西药中有效成分的方法.对DART离子源的离子化温度、扫描模式、操作气体种类、辅助溶剂种类及其酸碱性等实验条件进行了优化,得到最佳实验条件.实验结果表明,正谱条件下,采用N2气作为操作气体时,待测组分准分子离子峰[M+H]+同样具有较高的灵敏度和谱图辨识度.因此,N2气可以替代昂贵的He气作为DART离子源的操作气体用于8种药物有效成分的现场实时检测.该方法具备成本低、快速和操作简便的特点.通过分析待测组分的特征碎片离子,发现了N2-DART离子源中的特征离子反应,包括氧化反应和重排反应.根据获得的特征碎片离子对N2-DART-MS中发生的反应机理进行推导,并结合理论计算对其进行验证.N2-DART-MS技术有望应用于复杂基质混合物的现场快速检测中.%Direct analysis in real time-mass spectrometry (DART-MS) was usually employed as a novel method for fast screening of target compounds in complex matrix samples.However,nitrogen direct analysis in real time (N2-DART) mass spectrometry(MS) analysis of labile compounds usually tends to be challenging because of its low ionization energy and complex background signals.In the current study,N2-DART ion source coupled with high resolution Orbitrap MS based on a make-up solvent approach,which was designed for analysis of pharmaceuticals sensitively and easily,was reported.The main parameters of ion source,including gas temperature,gas type,scan mode,and solvent effect,were studied.The results confirmed that,compared with conventional He-DART,N2-DART could generate obviously different ions in positive ion mode.And the sensitivity obtained by N2-DART was found to be comparable with that obtained by He-DART.Typical mechanisms including the reactions of oxidation and rearrangement in N2-DART were also discussed in detail.For the purpose of further confirmation,theoretical calculation was employed to verify the feasibility of the rearrangement reaction.The results demonstrated that N2-DART-MS could provide a rapid and reliable method for the identification of active ingredients in pharmaceuticals,and may be applicable to other mixtures.