Fragmentation efficiency of phenethylamines in electrospray ionization source estimated by theoretical chemistry calculation
Fragmentation efficiency of phenethylamines in electrospray ionization source estimated by theoretical chemistry calculation
复制标题
通过理论化学计算估算电喷雾电离源中苯乙胺的裂解效率
DOI：
10.1002/jms.4802
复制
发表时间：
2021
影响因子：
2.3
通讯作者：
Saikusa Kazumi
中科院分区：
文献类型：
--
作者：
Asakawa Daiki;Saikusa Kazumi
具有极性官能团的小分子，包括取代的苯乙胺，通常通过液相色谱-质谱法（LC-MS）和电喷雾电离（ESI）进行分析。分析物分子大多以质子化和阳离子加合物的形式通过正离子电喷雾电离质谱（ESI-MS）检测。然而，取代苯乙胺的ESI通常通过ESI源内碰撞诱导解离（IS-CID）提供强烈的碎片离子信号，这阻碍了苯乙胺的明确鉴定。将该现象近似为单分子解离模型，并通过各种量子化学计算来评估解离效率以确定ESI IS-CID效率。采用post-Hartree-Fock（post-HF）方法CCSD（t）/cc-pVTZ//MP2（full）/6 - 311++G（d，p）计算苯乙胺的离解阈能，计算结果与实验数据一致。与后HF方法相比，利用具有合适泛函的密度泛函理论计算被认为是一种准确且具有竞争力的低成本方法。特别是ω B 97-XD、M06 - 2X-D3和最近开发的明尼苏达泛函，如M11、MN 12-SX和MN 15，提供了可靠的结果，就像后HF方法一样。最近开发的双杂交泛函DSD-PEBP 86-D3（BJ），PBE 0-DH和PBE-QIDH获得的结果也是可靠的。考虑ESI IS-CID有助于分析物分子的鉴定，因为除N-甲基化类似物外，大多数苯乙胺在ESI质谱中提供强信号。
Small molecules with polar functional groups, including substituted phenethylamines, are commonly analyzed by liquid chromatography‐mass spectrometry (LC‐MS) with electrospray ionization (ESI). Analyte molecules are mostly detected in protonated and cation‐adducted forms through positive‐ion electrospray ionization‐mass spectrometry (ESI‐MS). However, the ESI of substituted phenethylamines commonly provides an intense signal of fragment ions by ESI in‐source collision‐induced dissociation (IS‐CID), which hinders the unambiguous identification of phenethylamines. This phenomenon was approximated as a unimolecular dissociation model, and the dissociation efficiency was evaluated by various quantum chemistry calculations to determine the ESI IS‐CID efficiency. The calculated results were consistent with the experimental data, when the dissociation threshold energy of phenethylamines was calculated using the post‐Hartree‐Fock (post‐HF) method, CCSD(t)/cc‐pVTZ//MP2(full)/6‐311++G(d,p). In contrast to post‐HF methods, the utilization of density functional theory calculations with a suitable functional is recognized as an accurate and competitive low‐cost approach. In particular, ωB97‐XD, M06‐2X‐D3, and recently developed Minnesota functionals, such as M11, MN12‐SX, and MN15, provided reliable results, as in the case of the post‐HF method. The results obtained by the recently developed double hybrid functionals, DSD‐PEBP86‐D3(BJ), PBE0‐DH, and PBE‐QIDH, were also reliable. The consideration of ESI IS‐CID can facilitate the identification of analyte molecules because most phenethylamines, except forN‐methylated analogs, provide an intense signal in the ESI mass spectrum.