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UV-transparent gel tray - Gel electrophoresis (Sep/29/2009 )

Hello!
I am used to carry my gels into the so called "UV-transparent gel tray" and place the all thing on top of a UV-transluminator in order to visualize my DNA and take a nice picture.
In my new lab however this is against the rules, since apparently the UV exposition would ""fragilize"" the plastic that eventually would break easily.

In my experience: I forgot once in my previous lab a tray overnight on top of the transluminator and in the morning it was "tanned" and not anymore transparent to UV... but did not break down and was still perfectly suitable for his first job: holding the agarose in place.


If possible I would love to keep putting the tray on the transluminator and I am also very curious to hear your thoughts about that.
I am looking for technical details about the trays and so far the best I could find is this


**********************************************************************
Table 2.5
Percent UV transmittance through 1/4 (.64 cm) UV-transparent plastic (UVTP)
Approximate
Wavelength (nm) ----% Transmittance
254 -------------------- 0
302 -------------------- 80
366 -------------------- 90

************************************************************************

Although I am not sure how to interpret it

Thanks for any comments!

-bac-

bac on Sep 29 2009, 09:54 PM said:

Hello!
I am used to carry my gels into the so called "UV-transparent gel tray" and place the all thing on top of a UV-transluminator in order to visualize my DNA and take a nice picture.
In my new lab however this is against the rules, since apparently the UV exposition would ""fragilize"" the plastic that eventually would break easily.

In my experience: I forgot once in my previous lab a tray overnight on top of the transluminator and in the morning it was "tanned" and not anymore transparent to UV... but did not break down and was still perfectly suitable for his first job: holding the agarose in place.


If possible I would love to keep putting the tray on the transluminator and I am also very curious to hear your thoughts about that.
I am looking for technical details about the trays and so far the best I could find is this


**********************************************************************
Table 2.5
Percent UV transmittance through 1/4 (.64 cm) UV-transparent plastic (UVTP)
Approximate
Wavelength (nm) ----% Transmittance
254 -------------------- 0
302 -------------------- 80
366 -------------------- 90

************************************************************************

Although I am not sure how to interpret it

Thanks for any comments!



If I remember right only the absorbed UV will have effects, the transmitted will go through without much or any effect (though I'm not sure anymore if this is correct).
Anyway UV degradation is a long term effect and with the very short exposure times on the transilluminator, I wonder if it will have an observable effect during the time the persons work there. I guess the whole gel chamber is replaced before this...
Perhaps you should ask the manufacturer how stable their plastics are or if there are any UV Stabilizers are added. And it depends on the type of plastics, some are really susceptible, some are stable, I guess if anything the latter are used.

-hobglobin-

Thanks hobglobin.
good point: I emailed biorad (by the way the tray are this kind: Catalog # 170-4406)

Indeed googleing one can find a lot of pages on different plastics properties.
About the biorad tray everywhere it's mentioned they are UV-transparent. They do not even mention the exact material the trays are made, unless I missed it. If % Transmittance I reported below is the answer to my own question, I am not able to interpret it.

I would assume it is as hobglobin said: there must be some additive that protect it, which one? how does it work, I hope biorad will answer my questions, meanwhile I am still curious to hear what is the general behavior and thoughts of the participant of this forum
Thanks!

-bac-

I put the tray on the transilluminator and switch on quickly (after putting the transparent shield down of course) to make sure my products have moved far enough, so if they haven't I don't risk breaking my gel by having to put it back on the tray.
If ok, I then slide gel off onto the transilluminator to take the photo. I find I get a much better picture when the gel is off the tray.

-leelee-