生物源挥发性有机物（BVOCs）在大气中通过光氧化反应会产生大量的二次有机气溶胶（SOA），引发一系列的环境问题，近年来备受关注。BVOCs在大气中的寿命短、浓度低、时空变化快，而且存在有多种同分异构体和同质异位素，目前针对BVOCs的在线测量，还缺少行之有效的测量仪器和方法。本申请拟采用源内碰撞诱导解离（CID）-高精度飞行时间质谱，结合光电离技术，发展一种快速在线测量BVOCs的方法。本研究将在较高气压下的光电离源中，发展碰撞能量可控的源内CID，实现对BVOCs中同分异构体的分辨；利用高分辨和高质量精度的光电离质谱图，对BOVCs中同质异位素进行直接的定性和定量分析；同时使用无窗射频放电灯产生高强度的VUV光束，提高电离效率和检测灵敏度。整个检测时间小于10 s。本项目将为深入研究BVOCs在大气中的光化学反应过程以及SOA的形成机制提供可靠的检测技术和方法。

The atmospheric photooxidation of biogenic volatile organic compounds (BVOCs) can produce plenty of secondary organic aerosols (SOA), which causes a lot of environmental problems, and thus has attracted much attention in recent years. BVOCs in the atmospheric environment have short lifetime, low concentration, and fast temporal and spatial variation, and exist as complex mixtures with lots of isomers and isobars. The lack of feasible instruments and effective methods has become the main obstacle for online measurement of BVOCs at present. The technology of in-source collision-induced dissociation (CID) time-of-flight mass spectrometry combined with photoionization will be adopted in this project to develop a method for rapid online measurement of BVOCs. In-source CID with controllable collisional energy will be achieved in the photoionization ion source with higher pressure, and is to be used for differentiation of BVOCs isomers. The isobars of BOVCs can be directly qualitative and quantitative analyzed by using photoionization mass spectra with high resolution and high accuracy. Meanwhile, a windowless radio frequency (RF) discharge lamp is to be utilized to generate high-intensity vacuum ultraviolet (VUV) light beam, and eventually improve the ionization efficiency and detection sensitivity. The whole detection time will be less than 10 s. This project will provide reliable technology and method for intensive research of the photochemical reaction of atmospheric BVOCs and the formation mechanism of SOA.