Re: Formic Acid!

From:Barry Rittman <>

I prefer to use Kristensen's solution (1948). This is a mixture of
sodium formate formic acid.
340 gms sodium formate
1700 ml. 90% w/v formic acid.
Distilled water to 10 liters
can be made up and stored at RT for several months.
Need to use in a fume hood.
Need to have specimen well fixed before starting decalcification.
As Gayle pointed out this c an be used fro some IHC especially if
decalcifying at cold temperatures.

For large specimens such as entire dog jaws can use a  much lower
concentration with approximately 1-2% concentration of formic acid and
this allows some control. Need to stop maceration when carrying out
longer term decalcification by refixing in NBF.

I cannot agree with Gayle re adding hydrochloric acid to a formic acid
mixture. While this may speed up the decalcification process, it has a
tendency to swell and as she pointed out to overdecalcify. Hydrochloric
acid alone has been used for some studies for IHC against some types of
If you are looking for speed and routine histology can still use 1-5%
nitric acid with meticulous attention to end point. I prefer using
X-rays (if they are available to you).

Barry R. J. Rittman, Ph.D.
UTHHSC Dental Branch
6156 John Freeman avenue
Houston, TX. 77030


>                 Hello Histonetters!  I promise, no more questions
> concerning Elmer's Glue!:-)  My next quandry.......what kind of formic
> acid do you use for bone decalcification?  I have looked in the Sigma
> catalog and there are many to choose from. Also is the final pH a
> concern or do you just prepare a 5% solution?  I did consult my
> histology books but there isn't too much detail.  Thank you for any
> suggestions!
> Jennifer Hoover
> Eli Lilly and Company

<< Previous Message | Next Message >>