[Histonet] Re: 37% formaldehyde in the UK

John Auld John.Auld <@t> whnt.nhs.uk
Fri Feb 4 03:56:04 CST 2005


In the UK formaldehyde is a gas the concentrate bought is 37 - 40% gas
dissolved in water. This is then diluted to 4% gas in water, or 10% of the
commercial concentrate. Unfortunately there is no formal (sorry for the
pun) nomeclature for what is what. It is comonly accepted that formaldehyde
is the 37 - 40% concentrate and formalin (4% gas) is the diluted form.
While this may seem confusing I would be surpised at any histologist
attempting to use concentrated formaldehyde for histology. It is sometimes
used to fumigate saftey cabinets and cryostats though.


John Auld MSc CSci FIBMS
Dept of Histopathology and Clinical Cytology
Arrowe Park Hospital
Arrowe Park Road

Internal extn 2560
External Tel 0151 604 7025
From: LEWIS, MARK A. [mailto:mark.lewis <@t> thermo.com]
Sent: 04 February 2005 08:53
To: Linda Blazek; RossS <@t> BaylorHealth.edu; brett_connolly <@t> merck.com;
histonet <@t> pathology.swmed.edu
Subject: RE: [Histonet] 37% formaldehyde & the UK & Europe[Scanned]

Concerning Formaldehyde & Formalin.. I would like to hear from our
colleagues from around the world concerning the terminology and meaning of
the differences between Formaldehyde and Formalin. I was always under the
assumption that Formaldehyde was a gas "put" into water at it's highest
of 37 - 40 %. This 37-40% Formaldehyde when it is diluted with water then
becomes or receives the terminology called Formalin whether it is 10 %, 20%
etc... I am over in the UK and have been having some controversy with my
colleagues here in that they want to use "concentrated formalin" for a
particular procedure. If I take the formaldehyde purchased from my vendor
and make up what I call a concentrated solution ( 37% solution), I will
37% formalin, not the same thing. I feel that is confusing especially for
those of us across the ocean, because I will want to ask How concentrated?
If I hear the word formaldehyde, then I think of the 37-40% that we use to
make up our 10% NBF and I associate that in my mind as concentrate.  I
especially would like to hear from those in other countries across the
world. I even looked at a bottle of Formaldehyde that they have and it says
Formaldehyde (formalin). I'm going to search some texts and talk to some
chemists just because I want to be saying the correct thing without
confusing everyone when it comes to the procedure being done.
Thanks !

Mark Lewis

More information about the Histonet mailing list