Development of the Molecular Isomer Resolving Aerosol Collector and Analyzer (MIRACA) for Organic Aerosol Chemical Characterization

YAN WEN, Sarah Ellies, Yeongkwon Son, Andrey Khlystov, Desert Research Institute

     Abstract Number: 483
     Working Group: Instrumentation and Methods

Abstract
To address the need for high-time resolution measurements of detailed chemical composition of organic aerosols (OA), we are developing a molecular isomer resolving aerosol collector and analyzer (MIRACA). The device combines automatic aerosol collection and extraction using solvents of different polarity. The collected aerosol extracts can be either collected for offline analysis or analyzed on-line if coupled to an analytical instrument. By using a liquid chromatograph – ion mobility – high resolution mass spectrometer (LC-IM-HRMS), molecular isomers in the collected samples can be resolved. The goal is to enable rapid measurements highly-resolved chemical composition of both particulate and gaseous components of OA, with a particular focus on biomass burning aerosols. We developed and tested two proof-of-concept prototypes: one using an impactor for particle collection and one using a filter. The gas phase components are collected using a sorbent cartridge. To evaluate MIRACA’s performance, laboratory-generated levoglucosan and pyrene aerosols were collected and extracted, demonstrating the device’s ability to accurately quantify OA composition. The prototype was then applied to measure levoglucosan and major polycyclic aromatic hydrocarbons (PAHs) in aerosols from controlled laboratory-scale biomass burns, completing sample collection and extraction within one hour.