With this award from the Chemistry Major Research Instrumentation Program, Professor Barbara Finlayson-Pitts from University of California Irvine and colleagues Michael Kleinman, Sergey Nizkorodov, Donald Blake and Eric Saltzman will acquire an atmospheric pressure QTrap mass spectrometer that is capable of highly sensitive and specific measurements of both gases and particles. The instrument is capable of carrying out tandem experiments involving molecular analysis of secondary organic aerosols (SOA) using nano-desorption electrospray ionization (nano-DESI), extractive electrospray ionization (EESI), atmospheric solids analysis probe (ASAP) ionization and atmospheric pressure ionization (API). The proposal is aimed at enhancing research and education at all levels, especially in areas such as (a) determination of the products of isoprene photooxidation and the effects of relative humidity on the aerosol composition; (b) real-time measurements of the composition of SOA particles formed in complex volatile organic compounds (VOCs)-nitrogen dioxide-ozone mixtures; (c) elucidation of the efficiency of aerosol mass spectrometry (AMS) for measurements of organic nitrates by comparison to Fourier Transform infrared (FTIR) measurements; (d) measurement of VOCs in tobacco smoke; (e) measurement of nitrogen-containing VOCs from isoprene photooxidation; (f) determination of products of photochemical oxidations of aqueous phase acids and aldehydes; (g) real-time measurement of gaseous precursors and products in an aerosol flow tube during new particle formation and growth; (h) real-time measurement of gaseous p-cymene from the reaction of alpha-pinene with ozone, OH, and nitrate; (i) measurement of oxygen/carbon ratios of SOA and comparison to results from high-resolution electrospray ionization mass spectrometry; (i) real-time measurements of acetone and other oxygenated organic species during a cruise that is part of a North Atlantic gas flux study as well as other research activities.
Mass Spectrometry (MS) is one of the key analytical methods used to identify and characterize small quantities of chemical species embedded in complex matrices. In a typical experiment, the components flow into a mass spectrometer where they are ionized into the parent ion and its fragment ions and their masses are measured. This highly sensitive technique allows detection and determination of the structure of molecules in a complex mixture. An instrument with tandem capability provides additional structural identification power through further fragmentation of ions produced in the spectrometer. The instrumentation provided by this award will provide faculty and students in several departments the opportunity to pursue research projects using modern instrumentation not heretofore available at the institution. The research will impact not only the field of Chemistry but also provide important knowledge of atmospheric phenomena. The instrument will also be used in several laboratory courses to train significant numbers of students in the use of this important analytical technique.
