Simulating Prebiotic Earth Environments to Explore the Role of Aerosol Particles in Abiogenesis

STEPHANIE SALAS, Aaron Palmisano, Thomas Preston, Alexander Logozzo, James F. Davies, University of California, Riverside

     Abstract Number: 626
     Working Group: Aerosol Chemistry

Abstract
Approximately 4.5 billion years ago, prebiotic Earth had a reducing atmosphere; small amounts of free oxygen and higher amounts of carbon dioxide, ammonia, hydrogen cyanide, and other reactive species. Under intense early solar radiation, unique high-energy environments likely drove otherwise unfavorable chemical transformations. We are investigating the chemistry that could have occurred in aerosol droplets that led to the formation of peptide bonds which ultimately led to more complex biomolecules. Peptide bond formation is not thermodynamically favorable in bulk aqueous solution; however, aerosol droplets provide a unique environment for chemical reactions to occur. A recent collaboration with researchers at McGill University, utilizing aerosol optical tweezers and Raman spectroscopy, has identified the peptide bond formation, of diglycine, by aqueous droplets containing glycine and dicyandiamide (DCD), facilitated by air-water interfaces. It is believed that photochemically excited DCD reacts with glycine, followed by a condensation reaction with glycine which yields diglycine. Our current project aims to investigate this chemistry further by utilizing a linear quadrupole electrodynamic balance (LQ-EDB) to levitate individual particles and Mie resonance spectroscopy to determine the size and refractive index. The particles will be exposed to a blue laser to initiate photochemistry and be ejected individually from the LQ-EDB to an open port sampling interface (OPSI) and aspirated into the electrospray ionization source to be sampled by an Orbitrap Q Exactive mass spectrometer to determine the molecular composition of the levitated particles. By levitating and irradiating single particles with a blue laser, we aim to elucidate the photochemical reaction mechanism and kinetics of peptide bond formation. This approach will provide crucial insights into the role of aerosol chemistry during prebiotic Earth conditions in the emergence of early biomolecules.