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Project Progress

Co-Investigator Mark Smith and his research group have designed and built an aerosol flow generator to be used to study the photochemistry of organic aerosols and condensates. Currently, we are waiting for a liquid level sensor being built by the UA electronics shop. Once this component is assembled and tested, we can finish the assembly of the aerosol generator, which can then be tested and used to investigate the photochemistry of organic aerosols related to tholin materials.

We have also begun the chromatographic separation and structural spectroscopic investigations of very complex mixtures associated with both analysis of aerosol photoproducts and analysis of laboratory tholins. We have recently completed the installation of a dual electrospray ionization/matrix assisted laser desorption-ionization (ESI/MALDI) ion source on our 9.4 T Bruker ApexQh FT-ICR instrument. This source has been used to generate both positively and negatively charged ions by laser desorption ionization (LDI). Similarly to previous ESI investigations of laboratory tholins, we have detected more saturated amine and imine compounds in the positive ion mode. In the negative ion mode LDI spectra, we have observed highly unsaturated cyano derivatives, such as cyclopropylene tricyanide (C₆N₃) and a tetracyano pyrrole derivative (C₈N₅). Fragmentation studies of selected ions show the loss of HCN, C₂H₂N molecules and CH₃ radical. In addition, we are using this source to begin further analysis of new tholin samples produced by EUV radiation at the Advanced Light Source synchrotron. We have also acquired a new tunable (5-2000 eV) electron beam gun which will allow us soon to begin investigation of tholin aerosol generation as a function of electron beam kinetic energy to investigate the role of precipated electrons in Titan’s atmosphere in producing aerosol haze.

Preliminary HPLC/MS studies are showing encouraging results for the eventual separation of key components in tholin samples. This work is targeted towards production of chromatographically separated subcomponents which can be obtained in suitable quantity for structural analysis initially by multidimensional NMR.