RE: [Histonet] Osmium Tetroxide Protocol and mineral oil?

From:"Morken, Tim - Labvision"

Margaret wrote:

I have not ever seen a reference of mineral oil being used to "neutralize"
osmium. Osmium reacts with unsaturated oils and mineral oil, as far as I
know is fully saturated. In fact, I imagine that what happens is that the
osmium is simply dissolved in the mineral oil (similar to how it dissolves
in xylene). I really doubt the osmium is being neutralized by the mineral
oil. The following references give the proper procdure for using corn oil
(poly unsaturated) to neutralize osmium.

If you have a reference to support the mineral oil neutralization I'd
certainly like to see it.

Tim Morken


-----Original Message-----
From: Margaret Horne [] 
Sent: Wednesday, May 26, 2004 5:57 AM
Subject: Re: [Histonet] Osmium Tetroxide Protocol

Hi , when I handle osmium I always :

a) Carry the Osmium to the fume hood in a plastic container . ie. 
the Osmium solution is in a glass jar with a ground glass stopper 
and heavily parafilmed. Also the jar is covered in aluminum foil ( to 
avoid degradation from the light). This jar is Always carried about in 
a plastic container with a lid. Heavy rubbermaid or tupperware is 
good. Note that you will see the plastic container turn black over 
time with the Osmium fumes escaping. We keep it in the " Dirty " 
fridge , not the " Clean" fridge with our antibodies.

b) The plastic container is opened in the fume hood and I wear a  
labcoat and am Doubled Gloved. If the outer glove shows areas of 
black , then the glove integrety has been compromised and I 
replace the outer glove.  Double gloving can be uncomfortably tight. 
I found that a nitrile for the inner glove and a latex for the outer 
glove is comfortable for me but it depends on the fit of the gloves 
you use . In a pinch I have used two pair of latex.

c) Any glasswear that I use , I leave in the fume hood overnight for 
the fumes to evaporate.

d) I keep a container of oil in the fume hood when i am working with 
the osmium so I can pour oil on a spill if necesary or to neutralise 
the osmium if mixed with , say , blood , because it binds to lipids 
preferentially. I have used vegetable oil but it goes rancid over time. 
Mineral oil is fine.
        Remember that osmium fumes alone are sometimes used to 
fix tissue.  So working without proper ventilation means your 
eyeballs are going to become fixed.  Insist on a proper fume hood.

                       Other than that , it is not bad stuff to work with


ps. remember that osmium penetrates only 1 mm in depth so your 
tissue has  to be diced small.

Margaret Horne ,
Histology Teaching Assistant,
Dept. of B.SC.,
Atlantic Veterinary College, U.P.E.I.,
550 University Ave., Charlottetown,
P.E.I.,  C1A 4P3 

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