I am interested in the change of CO2 concentration inside bamboo stems. I have been using a syringe to pull air samples from inside the bamboo stem and inject it to a CO2 analyser (LI-6400 infra red gas analyser). Due to the mixing of sampled air and the background air through the analyzer, I need to integrate the curve of temporal change in concentration to derive the molar value of CO2 inside the syringe. This procedure is subject to substantial errors and I am wondering if there is a way (like a probe) to directly measure the CO2 concentration of a small air sample (like 3-5 ml).
Dear colleague, you should try use GC/FID or GC/TCD method
http://www.chem.agilent.com/en-US/products-services/Instruments-Systems/Gas-Chromatography/CO-CO2-Analyzers/Pages/default.aspx
ISliwka
Also see on my page
Measurements of Concentration of the Trace Gases Active in the Greenhouse Effect
J. Lasa, B. Drozdowicz, I. Śliwka, J. Rosiek
[Show abstract]
Geographia Polonica 01/1994; 62:47-59.
IS
I just have GC/TCD and GC/FID. I use GC/TCD to analyze soil respiration. You can try it in my lab.
Chien-teh
Ireneusz, thank you for your suggestion. That's perfect. How do I preserve the sampled gas before analyzing with GC/TCD or GC/FID? I was told that the sampled gas should be trapped in some liquid. I also like to analyze the delta13C of air samples in the near future.
Chien-Teh, that's perfect, let's plan on meeting and discuss in your lab next week. Is that okay?
GC. Sampling and analyze are no big deal , But how to keep you sample lid really "air-tight" was always the most difficult thing for all of us.
Dear Colleague
I think a glass 5 ml syringe is enough tightness. But you should estimate how many CO2 you expected in experiments. CO2 is a greenhouse gas and actual world concentration in outdoor air is 400 ppm. But in your breath concentration of CO2 is 4 %, that why you should protect experiment in glow box chamber flushed by synthetic air.
According to delta 13C analysis you should find cooperation with specialized laboratory in such analysis equipped in GC/MS system.
GC/FID in collaboration with Methanizer should do the trick. This assembly can be used in closed circuit continuous detection also means you can use this 'inline' also.
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