Re: CO2 grade for on-scope incubator?

Posted by Kurt Thorn on
URL: http://confocal-microscopy-list.275.s1.nabble.com/CO2-grade-for-on-scope-incubator-tp7582397p7582398.html

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Something seems weird here, since a live cell incubator needs to be
humidified to keep the cells from drying out. Typically, only the area
around the sample is kept in a 5% CO2 atmosphere, and this is also
humidified to close to 100%, so any water in the CO2 tank is negligible
compared to the amount of water added by the humidification system.

Even without this, unless you're in the desert, the air is often 50% or
greater relative humidity, so as soon as you mix the CO2 with air,
there's a fair amount of water present....

Kurt

On 7/22/2014 4:42 PM, Peter Werner wrote:

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>
> At our facility, we have a spinning-disk confocal system, with an
> incubator that surrounds the entire stage and substage area. The
> question I have concerns the type of CO2 I should be using for the
> incubator. I was told by someone from the UC Berkeley Biological
> Imaging Facility that I should be careful about the grade of carbon
> dioxide that I use - apparently, it should be high purity and as low
> as possible in H2O. The reason is, even if the cell cultures
> themselves will be fine with a lower purity of CO2, CO2 forms carbonic
> acid in reaction with water, and the acidified water content in the
> chamber atmosphere can be damaging to the instrument over the long
> term, hence, the less H2O mixed in with the CO2, the better. If this
> is the case, that would imply that "Instrument Grade" or "Bone Dry"
> grades would be what I need to use.
>
> I was wondering if anybody else knew of this recommendation and
> followed this practice. It makes sense to me why one would want to
> minimize carbonic acid formation in environments the confocal system
> is exposed to. On the other hand, it does entail some expense, not so
> much in terms of the gas itself, but in terms of special cylinders for
> high-purity CO2, which must be rented, or purchased at $500+ per gas
> cylinder.
>
> Let me know,
> Peter G. Werner
> Instructional Assistant/Lab Technician, Microscopy, Merritt College
> SEM/AFM Lab Technician, Ohlone College
> [hidden email]
>
>

--
Kurt Thorn
Director, Nikon Imaging Center
http://nic.ucsf.edu/blog/