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toxicity of methyl mercury

Chuck Miller rellim at MAILHOST.TCS.TULANE.EDU
Thu Jul 21 09:31:49 EST 1994


In a previous letter dvoon at uniwa.uwa.edu.au (Dominic Voon) wrote:
Hi all,
        I have started (probably not a good idea) to use Methyl Mercuric
Hydroxide as the DNA denaturant in my SSCP analysis. As I am doing a
"cold" SSCP (non-radioactive, faster and EtBr staining), it is critical
that I carry out the native PAGE in the cold room. This raises safety
concerns...
        The final concentration of MMH in my samples which I load into
the gel is 20mM (with a final volume of 20ul) and generally, it is believe
that concentration greater than 10mM should be handled in a chemical-hood.
        So the question I will like to ask is just how toxic is MMH ? I
don't want anyone (not the least myself) to get mercury poisoning. What
i am doing at the moment is to load the gel in a chemical-hood, seal the
upper buffer chamber from which any evaporation is likely, and run the
PAGE under an inverted  plastic box which will prevent any vapour from
escaping into the enclose environment that the cold room is. Is this safe
enough ? I have tried to run the PAGE OUTSIDE the cold-room in a
fumehood  but the results haven't been good...so I am really stuck.
Any suggestion will be much appreciated (no, we can't have a fumehood in
the cold-room :-( )

The "bible" of toxicology, Cassarett and Doull's Toxicology-The Basic
Science of Poisons states that the O.S.H.A. acceptable average conc. limit
for organo mercurials is 10ug/cubic meter of air for occupational exposure
periods of 8 hr./day. Thus, in your case toxicity is probably not a
problem. If you want to be "totally safe" you could get a PAGE gel
apparatus with a cooling buffer chamber (like a BIO-RAD model, etc.) and
hook it up to a refrigerated circulator pump. Then you could run a cold gel
in a room temperature hood.  

Best of luck,
Charles Miller
Tulane University




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