Development, characterization, and application of new analytical methodologies based on optical and mass spetrometry

我们团队正在研究和开发用于连接液相色谱(LC)和质谱仪(MS)的大气压电离源。为了扩大LC-MS的适用范围，提高LC-MS方法的灵敏度，最近发展了一种新的电离方法--大气压光电离(APPI)。我们正在进行的一个研究项目旨在阐明影响APPI源性能的基本机制，通过系统地研究电离区的光物理和气相化学，为APPI奠定坚实的理论基础。未来将开展研究项目，以研究对APPI来源的改进，以及开发新的API来源增强。更高的拉曼光谱可用于确定有关生物分子的结构和环境信息，在水溶液中的浓度相对较低，这使其成为一种非常强大的生物分析和生物物理技术。紫外共振拉曼光谱(UVRRS)正被用于研究蛋白质、多肽和DNA的结构和性质，以及生物分子的体内检测和表征。该小组将扩大其研究和表征生物分子系统的技术武器库，包括用于结构和动力学测量的飞秒相干反斯托克斯拉曼光谱。据报道，为了量化大气气溶胶的重要性，我们正在开发一种先进的单粒子气溶胶质谱仪，它将热激光解吸和近阈值光电离与离子陷阱质谱仪相结合，改进了现有的设计。完成的仪器将用于确定环境气溶胶的尺寸分辨化学成分，以及气溶胶成分的混合状态。这类信息对于了解大气中气溶胶的作用至关重要。

Our group is studying and developing atmospheric pressure ionization (API) sources for interfacing liquid chromatography (LC) with mass spectrometry (MS). In an effort to expand the range of compounds amenable to LC-MS, as well as to improve the sensitivity of LC-MS methods in general, a new ionization method, atmospheric pressure photoionization (APPI), has been recently developed. One of our ongoing research projects is aimed at elucidating the fundamental mechanisms responsible for the performance of the APPI source, to place APPI on a firm theoretical foundation through a systematic study of the photophysics and gas-phase chemistry in the ionization region. Future research projects will be undertaken to investigate improvements to the APPI source, as well as to develop novel API source enhancements.    Raman spectroscopy can be used to determine structural and environmental information concerning biomolecules, at relatively low concentration in aqueous solutions, which makes it a very powerful bioanalytical and biophysical technique. Ultraviolet resonance Raman spectroscopy (UVRRS) is being used for the study of the structure and properties of proteins, peptides, and DNA, and for the in-vivo detection and characterization of biomolecules.  The group will expand its arsenal of techniques for the study and characterization of biomolecular systems to include fs-coherent anti-Stokes Raman spectroscopy for structure and dynamics measurements.    In order to quantify the importance of atmospheric aerosols, we are developing an advanced single particle aerosol mass spectrometer that improves on current designs by combining thermal laser desorption and near threshold photoionization with ion trap mass spectrometry. The completed apparatus will be used to determine the size-resolved chemical composition of ambient aerosols, and the state of mixing of aerosol constituents. This type of information is critical for understanding the role of aerosols in the atmosphere.