[Nhcoll-l] Question about buffered formalin, what buffer should I use?

[Simon Moore]

Hi Esther,

You’ll probably get quite a few answers on this topic.  The standard fixation buffer for formalin that I use is a mix of phosphate salts:
•Phosphate buffer mix (6.5 parts Na2HPO4 and 4 parts NaH2PO4) is till one of the best and can be purchased mixed to the correct proportions.
•Sodium β-glycerophosphate is also a useful buffer. 

•Buffers (as for formalin) do not last for ever and formalin tested after 30 years had dropped to pH 4.
•If pH is a sensitive issue relating to the specimen, the pH may drop by 1 every 10 years or so.
With all good wishes, 

Simon Moore MIScT, RSci, FLS, ACR
Conservator of Natural Sciences and Cutlery Historian,

www.natural-history-conservation.com




> On 12 Feb 2021, at 09:27, Esther Dondorp <esther.dondorp at naturalis.nl> wrote:
> 
> Dear colleagues, 
> 
> I need your advice on what buffer to use to fixate a large eel in formalin.  I have to order 10% buffered formalin but I get the question from the chemical company what buffer they should add.  The pH should be around 7 I guess?
> 
> Many thanks and best regards,
> 
> Esther Dondorp
> Senior Collectiebeheerder
> 
> 
> 
> 
> 
> 
> 
> +31717519313 - -
> esther.dondorp at naturalis.nl - www.naturalis.nl
> Darwinweg 2, 2333 CR Leiden
> Postbus 9517, 2300 RA Leiden
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