Electrophoresis safety question

Dom Spinella dspinella at chugaibio.com
Tue Jun 16 16:44:32 EST 1998


Well folks, I'm the last person in the world to dismiss the importance
of laboratory safety, and all things being equal, I'd say leave the
cover on the gel rig while its running. On the other hand, in the
continuum of lab safety hazards, I'd have to rank an open mini gel rig
running at 100V pretty low.  I have accidentally dipped my hand in a
running gel tank more than once in the course of my bench career -- at
more than 100V and without gloves on (sigh...thought the damn thing was
turned off...).  From my experience, it gets your attention the way an
electric fence gets a cow's attention -- annoying and distinctly
unpleasant, but hardly lethal.  If you've got a pacemaker or a weak
heart, maybe there would be more danger, but I doubt a healthy adult
would be seriously injured by such a shock.   To be sure, I've never
managed to grab both electrodes while the rig was on, but it strikes me
that with most rigs, this would be next to impossible to do by accident.
Now, I'm sure that most of the current still flows through the buffer
instead of your hand when you place it inside a running gel box so maybe
I'm just lucky, or maybe I have an unusually high tolerance for pain
(probably a selected trait for any lab rat!).  But its hard for me to
work up to the kind of fear suggested by these postings.  Now if it were
a Sequencing rig running at 3000V,  I'd be a bit more concerned... Just
my opinion -- the usual dislaimers apply (on balance, its probably a
good thing that I'm not at the bench anymore!)
--Dom Spinella

> Hi Jen. 
> 
> I'd strongly recommend to run the chambers only with their lids on.
> 
> If your power supply outlet is not connected in any way with the 
> mains or the ground, touching ONE wire or the buffer with 
> ONE finger shouldn't harm you. 
> If you touch two wires of 100volts AC, you'll get an electric shock 
> that will blast you against the wall. It's probably like that one 
> you'll get when your heart doesn't beat and a doctor tries to 
> re-animate you with two electrodes placed on your chest.
> even if you immerse two fingers in the buffer, your fingers will be 
> in a voltage gradient, and a current will run through your fingers or 
> through you body, if you immerse both hands. 
> 
> It must not be a deadly shock that you'll receive but shurely it will 
> be one you will remember all your life. 
> 
> If you use a supply where mains voltage just passes a rectifier, 
> touching the apparatus with one hand probably will be the last 
> experiment you perform.
> 
> Some years ago, I touched the leads of an large capacitor 
> that was disconnected from the supply for some time but still had a 
> voltage of only 50 volts. (I measured the voltage 
> afterweards.) I still remember. But that's OT
> 
> We use chambers where the power supply wires come through the 
> lid, so we can't operate the apparatus without cover. That should be 
> a safety standard.
> 
> Electrophorese your experiment's proteins and genes, not yours.
> 
> Sorry for the drastic words
> Wolfi
> 
> > We run alot of horizontal agarose gels in our lab using standard
> > power packs at 100V (DC -- up to 3 amps) with 1X TAE running buffer.
> > 
> > A number of people run their gels without the lid on, meaning there
> > are open gel rigs running on the bench. My question is: Is this
> > dangerous, and, if so, how dangerous? I know that if I actually
> > touched the wires in the box I would be badly (fatally?) shocked. 
> > Would touching the buffer with one (unprotected) hand do anything to
> > me? With both hands? With nitrile gloves on?
> > 
> > I don't know enough about electricity to know how dangerous this is.
> > Intuitively, it seems bad, but in reality perhaps it isn't. I
> > always wear gloves when working around the boxes, because of EtBr,
> > but I am always a little worried about taking a gel out of a rig
> > only to find it on for some reason. It's not the sort of thing I
> > want to experiment with on my own, and was hoping someone with more
> > lab experience would have some insight into this.
> > 
> > Thanks in advance,
> > 
> > Jen Griffin
> > jgriffin at incyte.com
> > http://www.incyte.com
> > 
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> -----
> usual disclaimers apply * This message is RNAse free - please don't touch!
> ----- 
> Wolfgang Schechinger 
> University of Tuebingen, Germany
> email: wgschech at med.uni-tuebingen.de * wwWait:
> http://www.medizin.uni-tuebingen.de/~wgschech/start.htm
> -------



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