The temperature and relative humidity are variables that must be kept as controlled potential in my thesis, especially regarding relative humidity. I do not know of any easy way to do this.
Dear Juan, You can maintain relative humidities at very specific levels by keeping salt solutions in your incubator after Goffau et al (2009) (Bacterial pleomorphism and competition in relative humidity gradient. Environ Microbiol 11, 809-822). For example, a saturated solution of NaCl will produce a relative humidity of 75.2%, Na2SO4 91.0% etc at 20*C. We often put a 500ml beaker filled with a saturated solution into a larger plastic box that contains stacks of Petri dishes or other samples, and put that into the incubator. As long as the solution does not dry out and it is of sufficient volume, it will maintain humidity at the desired level. Regards, Andrew
It depends on what you are trying to do. Couldn't you use a standard CO2 chamber as a good temperature and humidity controlled environment?
What is the temperature and humidity ranges do you need? Also, what is the size of apparatus you would use?
Dear Juan, You can maintain relative humidities at very specific levels by keeping salt solutions in your incubator after Goffau et al (2009) (Bacterial pleomorphism and competition in relative humidity gradient. Environ Microbiol 11, 809-822). For example, a saturated solution of NaCl will produce a relative humidity of 75.2%, Na2SO4 91.0% etc at 20*C. We often put a 500ml beaker filled with a saturated solution into a larger plastic box that contains stacks of Petri dishes or other samples, and put that into the incubator. As long as the solution does not dry out and it is of sufficient volume, it will maintain humidity at the desired level. Regards, Andrew
The use of a salt solutions in a closed space works. Equilibrium at a given rH happens faster if the solution is in a small open container in a not to large sealed container. In an incubator, a small amount of salt solution may take a very long time to achieve a given rH, and you risk losing the rH "setting" for a while if you open the door very often.
A spectrum of salts allow you to pick a spectrum of rH values. Suggest you see: http://www.conservationphysics.org/satslt/satsol.php
It gives a reference to the definitive list of salts vs. rH:
Lewis Greenspan, 'Humidity fixed points of binary saturated aqueous solutions', J. of Research, National Bureau of Standards, 81A (1977) pp 89-96
Hi guys,
According to that paper, MilliQ (i.e., high-purity water) will give 100% relative humidity. Does that mean that if I put samples in a sealed box with a beaker of pure water, the result is an environment of 100% RH? (Assuming the box is not massively larger than the beaker).
http://nvlpubs.nist.gov/nistpubs/jres/81A/jresv81An1p89_A1b.pdf
http://www.conservationphysics.org/satslt/satsalt.php
Hello! I would like to prepare an environment of 0% Relative humidity in a desiccator at room temperature (22 ± 25 oC) in a desiccator with P2O5 (0% RH). Thus, I would like to know how much (Liter or mL) saturated salt solution that I do need in order to achieve such 0% RH environment.
Hello!! I also need control RH. It must be 85% at 85ºC?? Do you know some satured salt to do it?
Thank you,
You may consider a Cellkraft P-Series humidifier. Then you can easily change relative humidity for different sets of experiments if needed (and also during experiments). Quite a bit more costly than using salt solutions though. I am affiliated with Cellkraft.
http://cellkraft.se/humidityandsteam/flow-through-humidifiers/
How to maintain Relative Humidity in a carbonation chamber of size 6 ft x 4 ft X 4ft ?
Is there any mathematical relationship between volume of the chamber and quantity of Saturated solution required?
Hello, I ask how to prepare an environmemt 50% relative humidity. Best regards.
How can i achieve 95% relative humidity in a 40 cmx25cmx30 cm plastic container that i am using as a growth chamber?
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