[Histonet] 10% Neutral Buffered Formalin - Methanol?
darkdaym <@t> comcast.net
Wed Nov 17 13:53:32 CST 2010
The Methanol concentration of Formalin, 37% is frequently described on
the MSDS as 10-15%. However, I believe the actual Methanol
concentration is normally at the low end of that range. Both
Formaldehyde Gas and Methanol are Flammable.
Commercial 10% NBF typically contains about 1.1% Methanol and 3.7%
Formaldehyde. The Flash Point of this water solution defines it as a
Combustible Liquid. It is not correct to call it or handle as as a
Flammable Liquid and it does not normally require Flammable Liquid
storage and precautions. Let the Safety Officers of your institution
determine how you should handle and store these quantities of a
On 11/17/2010 10:42 AM, Geoff McAuliffe wrote:
> 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.
> 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.
>> Sharon Regional Health System is the area's largest hospital
>> and provider of health care services. Visit us online at
>> http://www.sharonregional.com for a complete listing of our
>> services, primary care physicians and specialists, and satellite
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