AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Determining Water Solubility Distribution of Organic Matters: Verification by the 1-Octanol-Water Partitioning Method and Application to Indonesian Biomass Burning Particles
Abstract Number: 51 Working Group: Aerosols, Clouds, and Climate
Abstract Organic matters (OM) are often separated into water-soluble and water-insoluble species. Water-soluble organic matters (WSOM) have been considered to contribute to hygroscopic property and cloud condensation nuclei activity. However, this classification is inadequate since water solubility of WSOM varies in a wide range. Recently, water solubility distribution started to be regarded as one of the important properties of WSOM as it plays a crucial role in affecting water uptake properties of WSOM. In order to better investigate relationship between water solubility distribution and water uptake property, we developed the 1-octanol-water partitioning method. With 1-octnaol-water partitioning coefficient (KOW), which is strongly correlated with water solubility, the method is able to categorize WSOM into different ranges of water solubility by changing volume ratio of 1-octanol and aqueous phases as well as extraction steps.
In this study, we verified the method by standard chemicals and applied the method to Indonesian biomass burning particles. Single and mixed atmospheric-relevant standard chemicals with a wide range of KOW were selected to examine accuracy of the 1-octanol-water partitioning method by a Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM). Afterwards, the method was applied to laboratory biomass burning particles. The sampled particles were dissolved in ultrapure water to extract WSOM. Subsequently, WSOM were classified into different ranges of water solubility using the 1-octanol-water partitioning method. After filtration, particles were regenerated by an atomizer then measured by ToF-ACSM. Water solubility distribution of the measured samples was estimated by the established data inversion algorithm. Derived mass spectra demonstrated that highly oxygenated species were highly water-soluble, while high molecular weight species tended to be less water-soluble.