Paul B. Farnsworth
BS, Brigham Young, University (1977)
Ph.D., University of Wisconsin (1981)
Postdoctoral Research, Indiana University (1981-82)
Visiting Scientist, Joint Research Center, Ispra, Italy (1989-90, 1998-1999)
Visiting Professor, University of Utah (2003)
My major area of research interest is analytical spectroscopy, with an emphasis on the development of new analytical techniques and instrumentation for trace molecular and elemental analysis. My group’s efforts are divided between two projects: the development and fundamental characterization of ambient ionization sources for molecular mass spectrometry, and studies of ion production and transport in plasma source mass spectrometers.
Changes in instrument response with changes in sample composition present a major challenge to users of ICP-MS. With laser excited atomic and ionic fluorescence, we measure ion densities and velocities at various locations in the differentially-pumped vacuum interface that separates the ICP from the mass spectrometer. We are using those measurements to develop a better understanding of how ions are transmitted through the interface, and how that transmission is affected by sample matrix.
A second set of experiments focuses on new atmospheric-pressure ionization techniques for mass spectrometric analysis, including DESI and DART. These new ion sources are capable of rapid analysis of a variety of samples with little or no sample preparation. However, the mechanisms by which they work have not yet well understood. We are drawing on our expertise in plasmas to develop a clearer understanding of the complex gas-phase chemistry that controls the performance of plasma-based ambient ionization sources and to develop new sensitive ambient ionization sources.
Work in my research group is challenging, yet rewarding. My students gain valuable exposure to mainstream analytical techniques, and at the same time gain practical experience with lasers, mechanical and electrical design, signal acquisition, and sophisticated data processing.
Additional research areas: Environmental chemistry, physical chemistry and spectroscopy