Development of Purge-and-Trap Sample Preconcentrator for Enhanced Detection of Alkyl Nitrates by Thermal Dissociation Cavity Ring-Down Spectroscopy

• Main Author: Ye, Connie
• Other Authors: Osthoff, Hans, Thurbide, Kevin, Gailer, Jürgen, Marriott, Robert
• Format: Master Thesis
• Language: English
• Published: Graduate Studies 2016
• Subjects: Chemistry > Analytical; Atmospheric Science; Cavity Ring-Down Spectroscopy; Alkyl nitrates; Orca
• Online Access: http://hdl.handle.net/11023/3510; https://doi.org/10.11575/PRISM/25688

This thesis describes the development of a sample preconcentrator for enhanced detection of alkyl nitrates (∑ANs) in ambient air by thermal dissociation cavity ring-down spectroscopy (TD-CRDS). The recovery of isopropyl nitrate on Tenax adsorbent was (96±1)% and unaffected by potential interfering gases such as ozone and nitrogen dioxide. Mixtures of five alkyl nitrates were also recovered in high yield in dry (99±5)% and in humidified air (92±11)% with relative humidity of 83%. Results from the first field deployment of the new instrument from the Ozone-depleting Reactions in a Coastal Atmosphere (ORCA) campaign are presented. The ORCA campaign took place at the Amphitrite Point Observatory on the West coast of Vancouver Island in Ucluelet, B,C. from July 6-31, 2015. A signal to noise ratio of 16.8 and a limit of detection of 7 pptv were demonstrated in the field. Future applications include measurements of isoprene and monoterpene nitrates.