Open-source solution for the automated sampling of soil head space gases for cavity ring-down spectroscopy
Abstract
Stable isotope respiration studies are the gold standard for tracing the mineralization of organic substrates in a soil. Laser-spectroscopy instruments have the potential to revolutionize these and other stable isotope studies by enabling rapid and continuous gas sampling with precision comparable to that found in isotope ratio mass spectrometry. While there are currently several high-quality, commercially available gas sampling systems that are compatible with these instruments, these systems often only allow users to use 8 or 16 sample vessels at a time, which may be insufficient for many soil incubation studies. This leaves custom-built systems the only viable option for automated sample handling in these larger studies, which can be a daunting task for those with no with experience in electronics or instrument design.
Here we share our design for an open-source automated gas multiplexer device designed to be compatible with Picarro cavity ring-down spectroscopy instruments, but which can be easily modified to function with other analytical instruments as well. The multiplexer is an expandable solenoid-based system made using primarily off-the-shelf components and is programmed using a custom software application. As a demonstration, we present results from laboratory incubation studies conducted using the multiplexer in conjunction with a Picarro G2201-I stable isotope gas analyzer to investigate the microbial mineralization of 13C labelled pyrogenic organic matter. This automated sampling approach allows for sub-daily measurements of CO2 concentration and isotopic composition and allows for fine-scale isotopic partitioning of headspace gases.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B21H2422B
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0428 Carbon cycling;
- BIOGEOSCIENCESDE: 0454 Isotopic composition and chemistry;
- BIOGEOSCIENCESDE: 1615 Biogeochemical cycles;
- processes;
- and modeling;
- GLOBAL CHANGE