We are conducting an experiment, where we are imitating a transport scenario of the House cricket, Acheta domesticus. In that matter, we want to measure RH% and CO2 inside the plastic transport container (10 x 10 x 6 cm). Both constant logging and momentary observations are fine.
Does anyone have a suggestion on how to measure CO2 inside the container, which does not require expensive and comprehensive equipment?
Thank you!
I suggest a CO2 flow through meter by Qubit https://qubitbiology.com/q-s151-co2-analyzer-0-2000ppm/. Have nitrogen flowing through at a rate of ~ one liter per min. In-line have a 30ml plastic bottle for a mixing chamber with a very small hole drilled into the side. Tape to cover it. In your chamber drill a very small hole in the side.
To calibrate: In a chamber of equal size as your test chamber flush with compressed air. Inject a ml into the 30 ml mixing bottle and measure your blank. Add a ml of pure CO2 to the calibration chamber, mix and plot peak. Another ml of CO2 added and plot again to get your calibration curve.
Sample Chamber: Flush it out with compressed air and add your pet. Making note of the time withdraw samples using a 1 ml syringe from the small hole in the chamber and inject it into the small hole in the 30ml bottle so the chamber gas flows through the meter. Something like that.
I use this method testing CO2 in potting soils, compost, mulches etc to determine stability. I use a Sheer Drawstring Pouches Gift Bags from Amazon to hold the sample. I mix the air by shaking the wide mouth Mason Jar (hole in top) with the bags inside. You might be able to place the cricket in one of these bags if they don't chew through. And gently shake to mix the gases.
If you take a ml or two out of the chamber you can keep the experiment running until you get readings. Use a small chamber (or more cricks) if needed.
I have done hundreds of these and can provide more info if you want.
You could try the soda lime method.
https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/0012-9658%281998%29079%5B1467%3ACFMUSL%5D2.0.CO%3B2?casa_token=KNsstRCCfz8AAAAA%3A8ImbDMZu8bK2JbdHEH40XjE5xpMAmQYEHMmlMrgkw-BJOUHcaUK9ijS0uNi3C2o1Q0-xtqjyhXt_ZOE
Just be certain to include controls with soda lime and without the crickets to subtract from the mass of the soda lime to account for the CO2 already present in the atmosphere.
Senseair K30 sensors are small and relatively cheap. This paper provides how to wire the electrical board to program and read the data:
https://bg.copernicus.org/articles/12/3849/2015/bg-12-3849-2015-discussion.html
Hope this helps
Cheers
Alberto