An Experimental and Theoretical Study of Laser Postionization of Femtosecond-Laser-Desorbed Drug Molecules
An Experimental and Theoretical Study of Laser Postionization of Femtosecond-Laser-Desorbed Drug Molecules
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DOI：
10.1021/acs.jpclett.0c02365
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发表时间：
2020-10-15
影响因子：
5.7
通讯作者：
Hanley，Luke
中科院分区：
文献类型：
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作者：
Pieterse，Cornelius L.;Rungger，Ivan;Hanley，Luke
使用7.9 eV单光子电离（7.9 eV fs-LDPI-MS）的飞秒激光解吸定位质谱法检测到先前通过二次离子质谱法发现具有非常低的电离效率的四种药物化合物中的三种。这四种药物化合物的电离能和其他性质的电子结构计算预测，所有显示电离能低于7.9 eV的光子能量，所需的单光子电离。卡马西平、丙咪嗪和维拉帕米的7.9 eV fs-LDPI-MS均显示出显著的前体（M+）离子信号，但未观察到环丙沙星的代表性信号。此外，7.9 eV fs-LDPI-MS显示出更高的M+信号和大多数相似的碎片离子相比，70 eV电子轰击质谱。电离和碎裂模式进行了讨论的最高占有分子轨道的计算波函数。还考虑了改善药物化合物的MS成像的横向分辨率和灵敏度的影响。
Femtosecond laser desorption postionization mass spectrometry using 7.9 eV single-photon ionization (7.9 eV fs-LDPI-MS) detected three of four drug compounds previously found to have very low ionization efficiencies by secondary ion mass spectrometry. Electronic structure calculations of the ionization energies and other properties of these four drug compounds predicted that all display ionization energies below the 7.9 eV photon energy, as required for single-photon ionization. The 7.9 eV fs-LDPI-MS of carbamazepine, imipramine, and verapamil all showed significant precursor (M+) ion signal, but no representative signal was observed for ciprofloxacin. Furthermore, 7.9 eV fs-LDPI-MS displayed higher M+signals and mostly similar fragment ions compared with 70 eV electron impact mass spectrometry. Ionization and fragmentation patterns are discussed in terms of calculated wave functions for the highest occupied molecular orbitals. The implications for improving lateral resolution and sensitivity of MS imaging of drug compounds are also considered.