Presentation Title

Comparison of HPLC and GC Analytical Techniques for the Determination of Atmospherically Relevant Reaction Products

Start Date

November 2016

End Date

November 2016

Location

HUB 302-#11

Type of Presentation

Poster

Abstract

Atmospheric aerosol are small solid or liquid phase particles suspended in the air that play a key role in the chemistry of the atmosphere. Aerosol particles can be generated from anthropogenic sources, e.g., vehicle exhaust, and biogenic sources, e.g., sea spray. Organic compounds, specifically dicarboxylic acids, comprise as much as 2% of the total aerosol mass originating from both sources. Further, aerosol particle composition can change while in the atmosphere through reaction with solar radiation or other atmospheric compounds. It is important to not only identify atmospheric reactants but also identify the reaction products that form to fully comprehend the effect aerosol particles have on climate. The aqueous phase photolysis of a prevalent dicarboxylic acid, succinic acid (C4), with hydroxyl radical, a prevalent atmospheric oxidizer, was performed in order to determine the photooxidation products as a function of hydroxyl radical concentration and reaction time. It is common, in the atmospheric community, to analyze aerosol samples using gas chromatography coupled to a flame ionization detector (GC-FID). However, this method requires samples to be dried and chemically derivatized prior to analysis, a process where more volatile reaction products could be lost or could result in inaccurate concentrations due to incomplete derivatization. In this study, the methods of high performance liquid chromatography (HPLC), which requires no additional sample preparation, and GC-FID were used to independently identify and quantify photooxidation products. Results comparing and contrasting the accuracy, consistency and analysis time of both instruments, as well as atmospheric implications, will be discussed.

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Comparison of HPLC and GC Analytical Techniques for the Determination of Atmospherically Relevant Reaction Products

HUB 302-#11

Atmospheric aerosol are small solid or liquid phase particles suspended in the air that play a key role in the chemistry of the atmosphere. Aerosol particles can be generated from anthropogenic sources, e.g., vehicle exhaust, and biogenic sources, e.g., sea spray. Organic compounds, specifically dicarboxylic acids, comprise as much as 2% of the total aerosol mass originating from both sources. Further, aerosol particle composition can change while in the atmosphere through reaction with solar radiation or other atmospheric compounds. It is important to not only identify atmospheric reactants but also identify the reaction products that form to fully comprehend the effect aerosol particles have on climate. The aqueous phase photolysis of a prevalent dicarboxylic acid, succinic acid (C4), with hydroxyl radical, a prevalent atmospheric oxidizer, was performed in order to determine the photooxidation products as a function of hydroxyl radical concentration and reaction time. It is common, in the atmospheric community, to analyze aerosol samples using gas chromatography coupled to a flame ionization detector (GC-FID). However, this method requires samples to be dried and chemically derivatized prior to analysis, a process where more volatile reaction products could be lost or could result in inaccurate concentrations due to incomplete derivatization. In this study, the methods of high performance liquid chromatography (HPLC), which requires no additional sample preparation, and GC-FID were used to independently identify and quantify photooxidation products. Results comparing and contrasting the accuracy, consistency and analysis time of both instruments, as well as atmospheric implications, will be discussed.