Atmospheric aerosol particles have a large and indeterminate effect on the Earth’s climate. Incoming solar radiation and outgoing terrestrial radiation can directly interact with aerosol particles which can scatter or absorb the radiation. This process can result in either a cooling effect on the Earth’s surface, where incoming solar radiation is scattered back to space or a warming effect, where outgoing infrared terrestrial radiation can be absorbed and reemitted back to the Earth’s surface. Radiative transfer calculations, a quantification of the radiative effects, are dependent on absorption and extinction parameters which are dependent on the chemical composition and phase of the aerosol particle. In this study, the optical properties of short-chain C2 – C6 α, ω-dicarboxylic acids are measured using infrared radiation. Five particular acids- oxalic, malonic, succinic, glutaric, and adipic acid, and mixtures thereof, have been characterized in the infrared fingerprint region from 1500 – 1000 cm-1 using a Fourier transform infrared (IR) spectrophotometer with a single bounce attenuated total reflectance cell (FTIR-ATR). The additive property of Beer’s Law is examined for spectra of mixtures by adding appropriate ratios of pure compounds. Results from this spectral math show inconsistencies in the absorbance of mixtures and pure compounds. As a result, algorithmic curve fitting is used to qualitatively and quantitatively identify the individual components from absorption spectra of the mixtures. Analysis of the results reveals the degree to which each pure dicarboxylic acid can be distinguished in the infrared region. The detection of each compound by our method will be discussed.

Characterization of short-chain dicarboxylic acids in the infrared region using Beer’s Law

253rd National Meeting (2017)

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