飞秒激光解吸单光子后电离技术的软电离效果研究  

Study on Soft Ionization Effect of Femtosecond Laser Desorption Single Photon Post-Ionization Technique

作　　者：许全凤 朱煜扬 冷宜昕 胡勇军 杭纬 XU Quan-Feng;ZHU Yu-Yang;LENG Yi-Xin;HU Yong-Jun;HANG Wei(MOE Key Laboratory of Spectrochemical Analysis and Instrumentation,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China;Guangzhou Key Laboratory of Spectral Analysis and Functional Probes,MOE Key Laboratory of Laser Life Science,College of Biophotonics,South China Normal University,Guangzhou 510631,China)

机构地区：[1]厦门大学化学化工学院,谱学分析与仪器教育部重点实验室,厦门361005 [2]华南师范大学生物光子学研究院,激光生命科学教育部重点实验室,广州市光谱分析与功能探针重点实验室,广州510631

出　　处：《分析化学》2024年第10期1508-1516,共9页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(No.22027808)资助。

摘　　要：激光作为质谱仪器常用的离子源,不仅可用于样品的直接解吸电离,还可用于中性分子的后电离,从而提高电离效率。为了探究单光子电离技术的电离效果,本研究采用515 nm波长的飞秒激光作为解吸源、118 nm波长的纳秒激光作为后电离源,通过实验室自行搭建的激光解吸-激光后电离飞行时间质谱仪(LDPI-TOFMS),对3类有机物质(吖啶类、吩噻嗪类和金属卟啉类化合物)进行分析。结果表明,单光子电离技术产生的碎片少,能保护分子离子不碎裂,特征离子峰和加合离子峰明显,可以实现对这些物质的软电离。同时,本研究采用266 nm波长的纳秒激光作为多光子后电离源进行对比,结果表明,多光子电离技术会使物质碎裂严重,产生较多的碎片离子,导致谱图难以解析,进一步证明了单光子后电离可作为一种软电离技术用于多种有机物的分析。激光解吸单光子后电离质谱法操作简单且无需复杂的样品前处理,有望为表面分析、薄层分析及复杂混合物分析提供一种高灵敏度和高特异性的分析方法。Lasers are widely utilized in ion sources for mass spectrometry.They can be employed to desorb and ionize samples directly or enhance the ionization efficiency of neutral molecules through post-ionization.To investigate the ionization characteristics of the single photon ionization technique,in this work,a femtosecond laser with a wavelength of 515 nm was utilized for desorption,and a nanosecond laser with a wavelength of 118 nm for post-ionization.A laboratory-built laser desorption/laser post-ionization time-of-flight mass spectrometer(LDPITOFMS)was used to analyze three types of organic substances including acridines,phenothiazines,and metal porphyrins.The results demonstrated that the single photon ionization method effectively reduced the fragment generation,safeguarded the molecular ions against fragmentation,and achieved soft ionization as indicated by the adductive and characteristic molecular ions.Furthermore,a 266-nm nanosecond laser was employed as a multiphoton post-ionization source for comparison.The outcomes indicated that molecules were significantly fragmented,and more fragmented ions were generated due to the multiphoton ionization technique,which complicated the spectral analysis.The comparison further demonstrated that the single-photon post-ionization technology could be utilized to analyze a variety of organic compounds via soft ionization.LDPI-TOFMS procedure was straightforward,and did not require intricate sample preparations.The laser desorption with single photon post-ionization mass spectrometry showed potential to offer a high level of sensitivity and specificity for surfaces,thin layers,and complicated sample analysis.

关 键 词：激光解吸 后电离 单光子电离 双光子电离 软电离 

分 类 号：O657.63[理学—分析化学]