Technical note: Intercomparison study of the elemental carbon radiocarbon analysis methods using synthetic known samples

Abstract

The accurate identification of elemental carbon (EC) sources in aerosol based on radiocarbon (14C) depends on the method of EC isolation. The lack of aerosol EC reference materials with "true"14C values makes it impossible to evaluate the accuracy of various methods for the analysis of 14C-EC in aerosols. In this study, EC isolation methods were evaluated by using samples of mixed biomass burning, vehicle exhaust, and coal combustion. The results show that 14C-EC was not only related to the isolation method but also to the types and proportions of biomass sources in the sample. The hydropyrolysis (Hypy) method, which can be used to isolate a highly stable portion of ECHypy and avoid charring, is a more effective and stable approach for the matrix-independent 14C quantification of EC in aerosols. The 13C-ECHypy and non-fossil ECHypy values of Standard Reference Material (SRM) 1649b were -24.9 ‰ and 11%, respectively.