Work

A new approach for measuring the carbon and oxygen content of atmospherically relevant compounds and mixtures

Year: 2020

Type: article

Abstract: . While the mass of particulate matter is monitored worldwide, only a few automated approaches exist to characterize its composition in any detail. All approaches require relatively high capital costs and complex operation by highly trained technical personnel. This leaves a major gap in understanding the health and environmental impacts of particulate matter. In this work, we demonstrate a new approach to estimate the mass of carbon and oxygen in analytes and mixtures that relies only on robust, moderate cost detectors designed for use with gas chromatography. Organic compounds entering a flame ionization detector were found to be converted with 95 % efficiency to CO2, which was analysed downstream using an infrared detector to measure the mass of carbon analysed. The ratio of FID signal generated per CO2 formed (FID / CO2) was shown to be strongly correlated (R2 = 0.89) to the oxygen-to-carbon ratio (O / C) of the analyte. Furthermore, simple mixtures of analytes behaved as the weighted average of their components, indicating that this correlation extends to mixtures. These properties were also observed to correlate well with the sensitivity of the FID estimated by structure activity relationships (quantified as the relative Effective Carbon Number). The relationships between measured FID / CO2, analyte O / C, and FID sensitivity allow estimation of one property from another with

Source: Atmospheric measurement techniques

DOI: 10.5194/amt-13-4911-2020