The complex chemistry at play in the sea surface microlayer (SSML) is driven in large part by the interactions of ions with both water and trace atmospheric gases. Characterizing these complex interactions often requires the development of novel instrumental approaches, bringing together new ion sources with methodology to facilitate the introduction of water or other reactive gases. To this end, we have taken on this challenge with two different instrumental approaches. The first was the development of ion transfer optics to interface a high resolution 7T FT ICR mass spectrometer to the commercially available Direct Analysis in Real Time (DART) ion source. The DART is an ambient pressure soft ionization source, well suited to ionizing the fragile fatty acid-metal ion complexes known to be present in the SSML and the surfaces of aerosol droplets. The second instrumental approach to this complex problem was the development and construction of a miniaturized version of Yale’s patented cryogenic ion spectrometer with interchangeable ion source technology so it could be interfaced to both a traditional electrospray ionization source as well as the DART. This new instrument has the ability to have the relative humidity precisely controlled in the ion trap, facilitating the uptake and mass characterization of water onto bare ions. These instrumental advances lead nicely to experiments designed to reveal the elementary chemical events which occur when N2O5 was condensed onto microhydrated chloride ion clusters to form ClNO2, a trace atmospheric gas which undergoes rapid photolysis into highly reactive Cl atoms. This was achieved by obtaining the vibrational spectral signatures of isolated cold, composition-selected ionic hydrated clusters frozen into minimum energy geometries.

Development of new instrumental approaches to characterize the fundamental chemistry of the sea surface microlayer

251st National Meeting (2016)

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