乙二醛与甲基乙二醛电子贴附电离检测中的关键科学问题研究

Glyoxal and methylglyoxal play as key roles in the atmospheric radical cycle and the quantitative analysis of these two species is of great importance. Mass spectrometry is a fast and sensitive method. This project is proposed to solve the problems of high-flux ionization as well as qualitative and quantitative characteriztion of product ions in the electron attachment ionization of glyoxal and methylglyoxal. Electron and ion trajectory simulation as well as a reflectron time-of-flight mass spectrometer coupled with a laser ablation source, a drift-tube reactor, and a photoelectron imaging spectroscopy will be used. On the basis of reactor improvement, product ion characterization by photoelectron imaging spectroscopy, choice of appropriate labelling molecules, and analysis of the influences under atmospheric species, the high-flux electron attachment ionization as well as qualitative and quantitative analysis of glyoxal and methylglyoxal will be established. This study will provide a fundamental basis for the mass spectromtric measurement of atmospheric glyoxal and methylglyoxal. The applicants of this project have rich experience on instrument design and application of mass spectrometry and photoelectron imaging spectroscopy in ion-molecule reactions.

乙二醛与甲基乙二醛是大气自由基循环中的关键物种，其定量检测具有重要意义。质谱检测具有快速灵敏的优点。本项目拟针对电子贴附电离检测乙二醛与甲基乙二醛中的高通量电离和产物离子的定性与定量检测展开研究。本项目拟采用激光溅射源、迁移管、反射式飞行时间质谱、光电子速度成像联用装置结合电子与离子轨迹模拟等技术，通过改进反应器、结合光电子速度成像指认产物结构、寻找合适的标定物并分析大气组分干扰，实现高通量电子贴附电离和乙二醛与甲基乙二醛的定性与定量检测，为研制大气乙二醛与甲基乙二醛检测的质谱装置奠定基础。本项目申请人在离子分子反应、质谱和光电子速度成像研究方面具有丰富的仪器设计和相关理论模拟经验。

乙二醛与甲基乙二醛是大气自由基循环中的关键物种，其定量检测具有重要意义。质谱检测具有快速灵敏的优点，但乙二醛与甲基乙二醛的无碎裂质谱检测尚未实现。本项目重点解决了乙二醛与甲基乙二醛电子贴附电离中的关键问题：1.乙二醛与甲基乙二醛标准样品的纯化与配制；2.低动能电子的高效产生与乙二醛和甲基乙二醛的高效电离；3. 乙二醛与甲基乙二醛电离产物的定性指认与大气监测适用性问题；4. 乙二醛与甲基乙二醛质谱检测的定量标定。.本项目成功建立了一套乙二醛与甲基乙二醛无碎裂质谱检测方法，此方法相较于商业化质子转移反应质谱具有分子离子无碎裂的优势，具有更高灵敏度且不易受空气湿度影响。基于此方法搭建了一套大气乙二醛与甲基乙二醛在线检测质谱。质谱样机成功实现了长期外场应用，在1分钟时间分辨率下实现了100 ppt的检测限。.本项目同时大气化学过程中乙二醛与甲基乙二醛的来源进行了研究。异戊二烯是大气乙二醛与甲基乙二醛的主要来源。研究发现了异戊二烯在颗粒物表面快速非均相氧化生成醛类物种的新机制，推算大气氧化铁纳米颗粒氧化异戊二烯总量与OH自由基氧化贡献量相当，并揭示了异戊二烯在纳米尺寸氧化钛阴离子团簇上光氧化的界面态调控机制。.在本项目支持下，发表检测方法与大气化学机制研究论文共计4篇。