Presentation Title

Method and analysis of the hygroscopic properties of alanine

Advisor Information

Joshua Darr

Location

Dr. C.C. and Mabel L. Criss Library

Presentation Type

Poster

Start Date

4-3-2016 9:00 AM

End Date

4-3-2016 10:30 AM

Abstract

Aerosols are a major component of the Earth’s atmosphere and are known to contribute greatly to the overall radiative balance. Aerosols are generated through various mechanisms, but sea-spray, from crashing waves, generates a significant amount of organic aerosols with the potential to affect the properties of well-studied inorganic salt aerosols. Out of these organic aerosols, simple water soluble biodegradation products such as alanine have been found to be one of the more prevalent compounds, making it important to study alanine’s aerosol optical properties in relation to radiative scattering. Because water content can affect an aerosol’s optical properties, it is first necessary to measure the hygroscopic properties of alanine. This can be done by probing their water absorption as a function of relative humidity (RH). The hygroscopicity of alanine was measured with an IR spectrometer using a flow cell apparatus. The aerosols were measured at different relative humidities (RHs) in order to observe their hygroscopic properties. This method underwent review and specific changes including a continuous sample compartment purge and longer path length cell were made in order to obtain quantitative measurements by increasing the overall signal to noise. This was accomplished successfully and signal to noise increased by factors up to 18. Even though the method was significantly improved alanine deliquescence was not observed within the limitations of our instrument. It is predicted that alanine deliquescence takes place at >90% RH.1 Alanine efflorescence was observed at 55–65% RH.

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COinS
 
Mar 4th, 9:00 AM Mar 4th, 10:30 AM

Method and analysis of the hygroscopic properties of alanine

Dr. C.C. and Mabel L. Criss Library

Aerosols are a major component of the Earth’s atmosphere and are known to contribute greatly to the overall radiative balance. Aerosols are generated through various mechanisms, but sea-spray, from crashing waves, generates a significant amount of organic aerosols with the potential to affect the properties of well-studied inorganic salt aerosols. Out of these organic aerosols, simple water soluble biodegradation products such as alanine have been found to be one of the more prevalent compounds, making it important to study alanine’s aerosol optical properties in relation to radiative scattering. Because water content can affect an aerosol’s optical properties, it is first necessary to measure the hygroscopic properties of alanine. This can be done by probing their water absorption as a function of relative humidity (RH). The hygroscopicity of alanine was measured with an IR spectrometer using a flow cell apparatus. The aerosols were measured at different relative humidities (RHs) in order to observe their hygroscopic properties. This method underwent review and specific changes including a continuous sample compartment purge and longer path length cell were made in order to obtain quantitative measurements by increasing the overall signal to noise. This was accomplished successfully and signal to noise increased by factors up to 18. Even though the method was significantly improved alanine deliquescence was not observed within the limitations of our instrument. It is predicted that alanine deliquescence takes place at >90% RH.1 Alanine efflorescence was observed at 55–65% RH.