A special lot of DEPC

Jan-Henner Wurmbach wurmbach at uke.uni-hamburg.de
Wed Apr 5 04:52:43 EST 2000


Errol <E.S.Kwan at massey.ac.nz> schrieb im Beitrag
<38ea6b4b.1287120571 at news.massey.ac.nz>...

> Isn't the bubbling normal?  I thought that the contact with the
> pipette tip catalysed the degradation of the DEPC to form ethanol and
> CO2.  Could the fruity smell be from the gas that they package into
> the bottle, they replace the air inside with another gas to prevent it
> from breaking down.

You have seen it also. Great, that is part of what I tried to find out :-)
 
> >PS.
> >I never had the feeling that DEPC is one of the greter hazards in a Lab.
> >Polyacrylamide, Ethidium bromide, PMSF or Phenole seemed to be far
greater
> >threads to our health.
> 
> Well the packaging with the DEPC says toxic so shouldn't you treat it
> as such? 

Well, I do.
I wear latex-gloves, open the bottle under the fumehood, pipette the needed
amont under the hood into the Water bottles (this is where I come to smell
it, must be pretty strong), close them, shake, and let stand over night
under the hood.
I take them out next morning, carry them to the autoclave and open the lid
of the bottle a little. After autoclaving the whole autoclave smells
"fruity" with the special smell I mentioned.

> This relaxed attitude towards toxic compounds is quite
> concerning.  From what I understand, smelling DEPC can result in death
> as it reacts in your lungs and will destroy the cells, 

This is is also true for SDS-powder, which we only weight under the
fumehood and with a face mask (.6 micron). You can feel it if the mask is
not fitting tightly - and it feels really hazardous.
But you HAVE to weight it. Sometimes - somewhere. So we make 2 litres of
20% solution once a year.
If DEPC is equally harmful I have to resort to making 30 litres on one day
and keep the bottle closed for the next week.
Until now me made our DEPC-Water "on demand", the day before or so.

> I've used it to
> open up Giardia cysts, 

I am ignorant I know: Giardia is a Bacterium?

(..)

> It was just hearing people say they're smelling DEPC that
> shocked me, when the warnings say no contact with skin, no inhalation
> etc.

I was not actively smelling it, in the sense of putting my nose over the
bottle!
I could not help smelling it, and I was asking public if this was normal.
As you report the bubbling after insertion of the Tip into the liquid
(which we never had before), and the smell which was also new, I asked if
someone had seen this before.
As this was happening in a new bottle that was accidentially left at RT
over the weekend, I thought that it might might be the effects of the
elevated temp.
But you report the bubbeling on the pipet tip and the smell may well be
some stabilising agent.
So I think that my DEPC is well and only the mode of packaging has been
changed.

Thank you for your help and the discussion
Especially Keld Sorensen for his concern!

Greetings
  Jan-Henner Wurmbach




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