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

我们的团队正在研究和开发大气压电离（API）源，用于连接液相色谱（LC）和质谱（MS）。为了扩大适用于LC-MS的化合物的范围，以及提高LC-MS方法的灵敏度，最近开发了一种新的电离方法，大气压光电离（APPI）。我们正在进行的研究项目之一是旨在阐明负责的APPI源的性能的基本机制，通过电离区域的物理和气相化学的系统研究，将APPI置于坚实的理论基础上。未来的研究项目将进行调查改进的APPI源，以及开发新的API源增强。 拉曼光谱可用于在水溶液中以相对低的浓度确定关于生物分子的结构和环境信息，这使其成为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）被用于研究蛋白质、肽和DNA的结构和性质，以及用于生物分子的体内检测和表征。 该小组将扩大其技术库的研究和表征的生物分子系统，包括飞秒相干反斯托克斯拉曼光谱的结构和动力学测量。 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，通过将热激光解吸和近阈值光电离与离子阱质谱相结合来改进当前的设计。完成的设备将用于确定环境气溶胶的尺寸分辨的化学成分，以及气溶胶成分的混合状态。这类信息对于了解气溶胶在大气中的作用至关重要。

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.