An optimised organic carbon ∕ elemental carbon (OC ∕ EC) fraction separation method for radiocarbon source apportionment applied to low-loaded Arctic aerosol filters ...

• Main Authors: Rauber, Martin, Salazar, Gary, Yttri, Karl Espen, Szidat, Sönke
• Format: Text
• Language: unknown
• Published: Copernicus Publications 2023
• Subjects: 570 Life sciences; biology; 540 Chemistry; Arctic
• Online Access: https://dx.doi.org/10.48350/178822; https://boris.unibe.ch/178822/

Radiocarbon (14C) analysis of carbonaceous aerosols is used for source apportionment, separating the carbon content into fossil vs. non-fossil origin, and is particularly useful when applied to subfractions of total carbon (TC), i.e. elemental carbon (EC), organic carbon (OC), water-soluble OC (WSOC), and water-insoluble OC (WINSOC). However, this requires an unbiased physical separation of these fractions, which is difficult to achieve. Separation of EC from OC using thermal–optical analysis (TOA) can cause EC loss during the OC removal step and form artificial EC from pyrolysis of OC (i.e. so-called charring), both distorting the 14C analysis of EC. Previous work has shown that water extraction reduces charring. Here, we apply a new combination of a WSOC extraction and 14C analysis method with an optimised OC/EC separation that is coupled with a novel approach of thermal-desorption modelling for compensation of EC losses. As water-soluble components promote the formation of pyrolytic carbon, water ...