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Evaluation of Thermal Optical Analysis (TOA) Using an Aqueous Binary Mixture



Courtney D. Grimes, Joseph Conny, Russell Dickerson


Thermal Optical Analysis (TOA), a commonly implemented technique used to measure the amount of particulate carbon in the atmosphere or deposited on a filter substrate, distinguishes organic carbon (OC) from elemental carbon (EC) through the monitoring of laser light, heating, and measuring evolved carbon. Here, we present a method to characterize the TOA transmission method with a binary solution containing EC and OC. The binary mixture is aqueous and can easily be deposited onto a filter at very low volumes. Known amounts of EC and OC were deposited onto a quartz-fiber filter and analyzed with different temperature protocols. Results with the NIST-EPA-C temperature protocol agreed with the reference values to better than 2 % for EC, OC, total carbon (TC), and EC/TC. Error in TC among all temperature protocols was less than 5 % of the reference value while all protocols had EC/TC ratios with an error less than 10 %.
Environmental Science & Technology


Black carbon, elemental carbon, organic carbon aerosol, thermal optical transmission analysis, TOT


Grimes, C. , Conny, J. and Dickerson, R. (2020), Evaluation of Thermal Optical Analysis (TOA) Using an Aqueous Binary Mixture, Environmental Science & Technology, [online], (Accessed April 16, 2024)
Created June 29, 2020, Updated October 12, 2021