激光非共振后电离/解离技术的研究和应用

本项目通过将激光解吸过程和电离过程在时间和空间上的分开独立优化，分别选择不同波长、脉宽、能量等条件的激光束进行解吸和电离，可以极大提高原子/分子利用率，极大提高电离效率，进而降低检出限。引入具有极低热效应和超短脉宽非线性吸收的飞秒激光实现解吸，不仅能降低采样量，还能减小基质干扰。通过对非共振后电离机理的研究，结合具体后电离激光参数的优化，得到电离效率高、普适性好、质量覆盖范围宽的电离参数，用于各类样品的多组分、高灵敏成分分析和成像分析。此外，由激光后电离产生的激光解离能够精确控制注入能量和作用时间，有望得到不亚于碰撞解离的碎片效果。通过对激光解离机理的研究，结合具体激光解离参数的优化，解决短时间内分子离子的光吸收效率低难题，产生更丰富的分子特征碎片信息，用于分子结构鉴定及同分异构体的区分。

By independently optimizing the laser desorption process and the ionization process in time and space, the project selects laser beams with different wavelengths, pulse widths, energy and other conditions, which can greatly improve the utilization of atoms and molecules and greatly improve the ionization efficiency, thereby reducing the detection limits. The introduction of a femtosecond laser with extremely low thermal effect and ultra-short pulse width nonlinear absorption not only reduces the sampling amount, but also reduces the matrix interference. Through the study of the non-resonance ionization mechanism and the optimization of the laser post-ionization parameters, high ionization efficiency, good universality and wide mass coverage can be obtained, which would be useful for high-sensitivity multi-component analysis and imaging analysis of various samples. In addition, the dissociation generated by laser post-ionization can be precisely controlled by the implantation energy and the action time. It is expected to obtain the fragmentation effect as much as the collision dissociation. Through the study of laser dissociation mechanism and the optimization of specific laser dissociation parameters, the problem of low light absorption efficiency of molecular ions in a short time can be solved, and more abundant molecular featured fragment information can be generated for molecular structure identification and isomer discrimination.