Assistant: Ann Mao
Major research interests include the development of new instruments and techniques for studies of the structures, reaction dynamics, and properties of organic, inorganic and biological molecules and ions in the gas phase, in solution, and at the air-water interface.
Current endeavors include development and application of reagents and methods for structure elucidation of proteins, glycans and lipids, investigations of the structure and reaction dynamics of complex molecules at gas-liquid interfaces, development of instrumentation for in situ elemental and chemical analysis on Mars and Titan, and the development of methods to detect potential biomarkers in cryovolcanic emissions from subsurface oceans on icy moons (e.g. Enceladus).
An exciting new experimental methodology being explored involves the use of tailored acoustic fields to trap millimeter droplets in the gas phase for extended periods of time. The technique of field induced droplet ionization, developed in our laboratory, makes it possible to sample intact molecules such as lipids and amphiphilic proteins from the air-water interface of the trapped droplet. This facilitates elucidation of the detailed reaction mechanisms of reactive species such as ozone and hydroxyl radicals with complex molecules at the air-water interface, with applications in environmental science. Photochemical studies can be conducted as well, an example being the elucidation of the mechanism of photodynamic cancer therapy used to treat squamous cell carcinomas of the neck and face.
New designs of acoustic levitators will make possible studies in which two droplets are brought together and mix on a sub-millisecond time scale. A contemplated application is the rupture of single cells, followed by mass spectrometric analysis of cell components.