Presentation Title

Quantification of Succinic Acid Aerosol Photooxidation Products Using HPLC and GC

Faculty Mentor

Paula K. Hudson

Start Date

18-11-2017 10:00 AM

End Date

18-11-2017 11:00 AM

Location

BSC-Ursa Minor 115

Session

Poster 1

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Aerosol particles are solid or liquid phase particles suspended in the air that are highly variable in both composition and size. Particles smaller than 10 micrometers in diameter (PM10) can be inhaled into the lungs affecting health while particles smaller than 2.5 micrometers in diameter (PM2.5) directly affect environmental visibility; both are affected by aerosol composition. Aerosol composition is determined from the aerosol source but can be altered through atmospheric reactions. For example, dicarboxylic acids are a prevalent organic aerosol emitted from car exhaust and meat cooking, but undergo oxidation reactions that change the original composition. It is important to identify atmospheric reactants and the reaction products that form to understand the effect aerosol particles have on human health and visibility. In this laboratory study, aqueous phase solutions of succinic acid (SA), a dicarboxylic acid, with varying concentrations of hydrogen peroxide (H2O2) were photolyzed to simulate the atmospheric oxidation of SA with hydroxyl radicals, a key atmospheric oxidizer. The time dependent photooxidation products were identified and quantified using high performance liquid chromatography and gas chromatography. The composition of resulting reaction products is highly dependent on the initial relative concentrations of reactants and total reaction time. Under conditions of excess H2O2(hydroxyl radicals), SA is rapidly oxidized to form malonic and oxalic acids, dicarboxylic acids with a shorter carbon chain length than SA. However, when H2O2 is the limiting reactant, larger poly-carboxylic acids like the succinic acid dimer are formed. Given the complex matrix of reaction products, human health and environmental visibility will be affected in a number of ways. However, proposed reaction mechanisms or the formation of photooxidation products of dicarboxylic acids can help us better understand, and predict, air quality.

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Nov 18th, 10:00 AM Nov 18th, 11:00 AM

Quantification of Succinic Acid Aerosol Photooxidation Products Using HPLC and GC

BSC-Ursa Minor 115

Aerosol particles are solid or liquid phase particles suspended in the air that are highly variable in both composition and size. Particles smaller than 10 micrometers in diameter (PM10) can be inhaled into the lungs affecting health while particles smaller than 2.5 micrometers in diameter (PM2.5) directly affect environmental visibility; both are affected by aerosol composition. Aerosol composition is determined from the aerosol source but can be altered through atmospheric reactions. For example, dicarboxylic acids are a prevalent organic aerosol emitted from car exhaust and meat cooking, but undergo oxidation reactions that change the original composition. It is important to identify atmospheric reactants and the reaction products that form to understand the effect aerosol particles have on human health and visibility. In this laboratory study, aqueous phase solutions of succinic acid (SA), a dicarboxylic acid, with varying concentrations of hydrogen peroxide (H2O2) were photolyzed to simulate the atmospheric oxidation of SA with hydroxyl radicals, a key atmospheric oxidizer. The time dependent photooxidation products were identified and quantified using high performance liquid chromatography and gas chromatography. The composition of resulting reaction products is highly dependent on the initial relative concentrations of reactants and total reaction time. Under conditions of excess H2O2(hydroxyl radicals), SA is rapidly oxidized to form malonic and oxalic acids, dicarboxylic acids with a shorter carbon chain length than SA. However, when H2O2 is the limiting reactant, larger poly-carboxylic acids like the succinic acid dimer are formed. Given the complex matrix of reaction products, human health and environmental visibility will be affected in a number of ways. However, proposed reaction mechanisms or the formation of photooxidation products of dicarboxylic acids can help us better understand, and predict, air quality.