[Histonet] 10% Neutral Buffered Formalin - Methanol?

[Geoff McAuliffe]

Commercially purchased 37% formaldehyde has had a small amount (about 
1.5% I think) of methanol added to it for many, many years. It helps to 
prevent the polymerization of formaldehyde into insoluble 
paraformaldehyde. It certainly does not make the stock solution 
flammable and it is not contributing to drying out of your tissues. 
Those who want methanol-free formalin make it from paraformaldehyde but 
for LM there is no point.

Geoff


Jones, Laura wrote:
> Greetings to all of you in Histoland.  Our lab recently switched from using a formalin substitute to using 10% Neutral Buffered Formalin.  Our Pathologists have been unhappy with the small tissues, like GI biopsies and prostate cores.  They say they are seeing too much chatter and poor nuclear detail.  We have adjusted our processing times with only mildly better results.
>
> Today, I arrived at work to find staff cramming boxes and boxes of prefilled formalin vials into flame cabinets, as JCAHO is here this week.  It occurred to me that 10% NBF was not considered flammable when we used it years ago, and I was surprised to find that the MSDS for the bottles we had ordered listed methanol as an ingredient.  I immediately went back to my early days in Histo, when we made up 10% NBF ourselves from 37% concentrate; and we did not have any alcohol in our "recipe".  I thought I had discovered our whole problem!  However, upon further research, we have found that most prefilled bottles DO contain methanol.  The large 20 litre cube, however does not list methanol as an ingredient.
>
> So, my questions are many.  Does that inclusion of methanol contribute to the drying out of tissues that we are seeing?  Does anyone sell prefilled bottles that contain methanol-free formalin?  And, finally, does anyone have any other thoughts or suggestions?  I should add that we use Toluene as our clearing agent, because our former Pathologist believed it was less harsh on the tissues; and we are running our tissues on the Thermo Excelsior.  We are running small biopsies and large pieces of tissue together, which I know is not optimal, but we are a small hospital and one processor is it!  I am not a chemist and would appreciate any advice.  Thanks in advance.
>
>
>
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Geoff McAuliffe, Ph.D.
Neuroscience and Cell Biology
Robert Wood Johnson Medical School
675 Hoes Lane, Piscataway, NJ 08854
voice: (732)-235-4583 
mcauliff <@t> umdnj.edu
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