10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Characterization of Polarity Distribution of Organic Aerosol via HPLC Coupled with Fast Aerosol Size Distribution Measurements
Vikram Pratap, Yuanyuan Zhang, SHUNSUKE NAKAO, Clarkson University
Abstract Number: 917 Working Group: Instrumentation
Abstract Polarity is one of the key parameters that determine hygroscopicity of organic aerosol (OA). The polarity of OA continuously evolves as OA undergoes oxidative processing. However, direct measurements of OA polarity are limited. This study aims to determine the volume fraction of organic materials with respect to polarity by coupling a reversed-phase high-performance liquid chromatograph (HPLC) and a fast mobility particle sizer (FMPS). The column effluent is aerosolized, dried, and introduced into the FMPS. Since atomization efficiency changes as a result of the mobile-phase gradient, a second binary pump operating at an opposite gradient is introduced to maintain a constant mobile-phase composition entering the atomizer. Results show that aerosol volume concentration determined by the FMPS is linearly proportional to the mass of sample introduced into the HPLC, confirming that aerosol detection can be used as a universal detection of analytes independent of chromophores. Unlike commercial universal detection techniques such as charged aerosol detection (CAD) that provides a proxy of solute volume, the new approach allows determination of aerosol size distribution, which has a potential to provide additional information of analyte properties. This study explores the feasibility of coupling the fast size distribution measurements with cloud condensation nuclei (CCN) measurement in order to determine polarity – hygroscopicity two-dimensional distributions of organic aerosol.