Hankin S M, Tasker A D, Robson L, Ledingham K W D, Fang X, McKenna P, McCanny T, Singhal R P, Kosmidis C, Tzallas P, Jaroszynski D A, Jones D R, Issac R C, Jamison S
Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK.
Rapid Commun Mass Spectrom. 2002;16(2):111-6. doi: 10.1002/rcm.553.
Femtosecond laser time-of-flight mass spectra of solid samples of trinitrobenzene (TNB), trinitrotoluene (TNT) and trinitrophenol (TNP) have been recorded. Desorption of the solid samples was enacted by the fourth harmonic output (266 nm) of a 5 ns Nd:YAG laser. Subsequent femtosecond post-ionisation of the plume of neutral molecules was achieved using 800 nm laser pulses of 80 fs duration. Mass spectra have been recorded for desorption laser intensities from 2-6 x 10(9) W cm(-2) with ionisation laser intensities between 2 x 10(14) and 6 x 10(15) W cm(-2). Femtosecond laser ionisation has been shown to be capable of generating precursor and characteristic high-mass fragment ions for labile nitro-aromatic molecules commonly used in high-explosive materials. This feature is critical in the future development of femtosecond laser-based analytical instruments that can be used for complex molecular identification and quantitative analysis of environmentally important labile molecules. Furthermore, a comparison of femtosecond post-ionisation mass spectra with standard 70 eV electron impact data has revealed similarities in the spectra and hence the fragmentation processes.
已记录了三硝基苯（TNB）、三硝基甲苯（TNT）和三硝基苯酚（TNP）固体样品的飞秒激光飞行时间质谱。固体样品的解吸由5 ns Nd:YAG激光的四次谐波输出（266 nm）实现。随后，使用持续时间为80 fs的800 nm激光脉冲对中性分子羽流进行飞秒后电离。已记录了解吸激光强度为2 - 6×10⁹ W cm⁻²且电离激光强度在2×10¹⁴至6×10¹⁵ W cm⁻²之间时的质谱。飞秒激光电离已被证明能够为常用于高爆炸材料的不稳定硝基芳香族分子生成前体离子和特征性高质量碎片离子。这一特性对于未来基于飞秒激光的分析仪器的发展至关重要，这类仪器可用于复杂分子的鉴定以及对环境中重要不稳定分子的定量分析。此外，飞秒后电离质谱与标准70 eV电子轰击数据的比较揭示了光谱以及裂解过程中的相似性。
