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  • An autonomous remotely operated gas chromatograph for chemically resolved monitoring of atmospheric volatile organic compounds
Title: An autonomous remotely operated gas chromatograph for chemically resolved monitoring of atmospheric volatile organic compounds
Volatile organic compounds (VOCs) range in their reaction rates with atmospheric oxidants by several orders of magnitude. Therefore, studying their atmospheric concentrations across seasons and years requires isomer resolution to fully understand their impact on oxidant budgets and secondary organic aerosol formation. An automated gas chromatograph/flame ionization detector (GC-FID) was developed for hourly sampling and analysis of C 5 –C 15 hydrocarbons at remote locations. Samples are collected on an air-cooled multibed adsorbent trap for preconcentration of hydrocarbons in the target volatility range, specifically designed to minimize dead volume and enable rapid heating and sample flushing. Instrument control uses custom electronics designed to allow flexible autonomous operation at moderate cost, with automated data transfer and processing. The instrument has been deployed for over two years with samples collected mid-canopy from the Virginia Forest Laboratory located in the Pace research forest in central Virginia. We present here the design of the instrument itself, control electronics, and calibration and data analysis approaches to facilitate the development of similar systems by the atmospheric chemistry community. Detection limits of all species are in the range of a few to tens of ppt and the instrument is suitable for detection of a wide range of biogenic, lightly oxygenated, and anthropogenic (predominantly hydrocarbon) compounds. Data from calibrations are examined to provide understanding of instrument stability and quantify uncertainty. In this work, we present challenges and recommendations for future deployments, as well as suggested adaptions to decrease required maintenance and increase instrument up-time. The presented design is particularly suitable for long-term and remote deployment campaigns where access, maintenance, and transport of materials are difficult.  more » « less
Award ID(s):
1837882 2046367
PAR ID:
10399086
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Environmental Science: Atmospheres
Volume:
3
Issue:
2
ISSN:
2634-3606
Page Range / eLocation ID:
387 to 398
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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