how dangerous is ethidium bromide

slavemaster un691cs at
Mon Dec 2 03:32:20 EST 1996

In article <Pine.SOL.3.95.961129201350.16670K-100000 at>, 
abrdlher at says...
>On 27 Nov 1996, Stefano casalotti wrote:
>> I generally put Ethidium bromide directly in the agarose gel but other
>> people prefer to stain the gel after, saying that it is safer. It seems to
>> me that one uses much lower concentrations  by applying directly in the
>> gel, but of course some of it will elute out in to the tank buffer
>> What is the safest method

For me, the main reason NOT to put EtBr in my gels, is that it may influence 
the migration behaviour of certain DNA fragments (supercoil binds less
EtBR. than linear DNA etc.etc.etc).
As EtBr is light and temperature sensitive, we store the stock at 4C
and color our gels in a metal, light thight box. After that you should incubate the
gel for appr. 2 minutes in H2O, otherwise there will be EtBr all over
your UV light again...
Just like any other lab chemical, I would advice you to use this substance
also with a lot of respect.


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