A set of fentanyl molecules when subjected to vacuum UV atmospheric pressure photoionization (VUV-APPI) in the presence of dopants (ammonia and anisole) shows two major bands in the ion mobility-mass spectrometry (IMS-MS) spectrum corresponding to (a) the protonated fentanyl, [M+H]+ and (b) a unique [M-74]+ ion. For the parent fentanyl, the [M-74]+ ion is at m/z 262 but, in the absence of ammonia, the product ion is shifted to m/z 245, corresponding to a difference of NH3. Collision-induced dissociations (CID) of the [M-74]+ ions for all the different fentanyls examined here show the same pattern of neutral losses, namely NH3 and HN=CH2, and the dominant product ion is at m/z 84 (shifted to m/z 98 for 3-methylfentanyl and m/z 142 and 231 for carfentanyl). Dissociation of the [M-74-NH3]+ ion derived from the fentanyls yields the same product ions as found in the electron impact (EI) ionization spectra of the fentanyls. The dissociation products of the [M-74-HN=CH2]+ ion are different, include the ion at m/z 84, and correspond to the fragmentation products of protonated norfentanyls. Theoretical modeling supports the opening of new fragmentation channels as a result of the reaction of the initially formed iminium cation with ammonia at atmospheric pressure.

中文翻译：

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在氨存在下通过大气压光电离产生的芬太尼衍生的阳离子：一项 IMS-MS 研究。

一组芬太尼分子在存在掺杂剂（氨和​​苯甲醚）的情况下进行真空紫外常压光电离 (VUV-APPI) 时，在离子迁移率 - 质谱 (IMS-MS) 光谱中显示两个主要谱带，对应于 (a)质子化的芬太尼、[M+H]+ 和 (b) 独特的 [M-74]+ 离子。对于母体芬太尼，[M-74]+ 离子位于 m/z 262，但在没有氨的情况下，产物离子移动到 m/z 245，对应于 NH3 的差异。此处检查的所有不同芬太尼的 [M-74]+ 离子的碰撞诱导解离 (CID) 显示出相同的中性损失模式，即 NH3 和 HN=CH2，主要产物离子位于 m/z 84（ 3-甲基芬太尼的 m/z 98 和卡芬太尼的 m/z 142 和 231）。源自芬太尼的 [M-74-NH3]+ 离子的解离产生与芬太尼的电子轰击 (EI) 电离谱中发现的相同的产物离子。[M-74-HN=CH2]+ 离子的解离产物不同，包括 m/z 84 处的离子，对应于质子化去甲芬太尼的裂解产物。理论模型支持由于最初形成的亚胺阳离子与氨在大气压下反应而打开新的碎裂通道。