[Nhcoll-l] Glycol-formalin interactions from pitfalls

[Simon Moore]

Hi Anna,

Formalin and the lower glycols will mix perfectly well and there are some fixative solutions that contain propylene glycol or ethylene glycol and formalin - the glycols acting as humectants.  There shouldn’t be any issues either with formalin fixing and then transferring to 70% ethanol but if there are soft tissues involved, you will need to use an increasing percentage alcohol dehydration ladder to prevent osmotic shrinkage of those tissues. 

With all good wishes, Simon 

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

www.natural-history-conservation.com


> On 24 Jul 2025, at 21:57, Chinn, Anna RBCM:EX <achinn at royalbcmuseum.bc.ca> wrote:
> 
> Hi everyone,
>  We have several hundred frozen small mammals that were originally collected from pitfall traps and that we are hoping to fluid preserve. By some word of mouth, we’ve heard that formalin used in fixation may adversely interact with any glycol remaining on the specimens from the pitfalls. We’ve read that transferring specimens from formalin into glycol will cause the glycol to go cloudy over time, but what about transferring specimens in the other direction? Has anyone had preservation issues with formalin-fixing pitfall mortalities, then storing the specimens in 70% ethanol?
>  Any advice or experience would be much appreciated. Thanks!
>  Anna
>  _____________________________________________________________________________________________
> Anna Chinn    Collection Manager, Birds and Mammals |  Collections Care and Conservation
> 
> 
> ROYAL BC MUSEUM
> Traditional Territory of the Lekwungen (Songhees and Xwsepsum Nations)
> 675 Belleville Street, Victoria, BC Canada V8W 9W2
> 
> achinn at royalbcmuseum.bc.ca | royalbcmuseum.bc.ca
> 
> Join us on: Facebook | Twitter | Flickr | Instagram | Website
>  _______________________________________________
> Nhcoll-l mailing list
> Nhcoll-l at mailman.yale.edu
> https://mailman.yale.edu/mailman/listinfo/nhcoll-l
> 
> _______________________________________________
> NHCOLL-L is brought to you by the Society for the Preservation of
> Natural History Collections (SPNHC), an international society whose
> mission is to improve the preservation, conservation and management of
> natural history collections to ensure their continuing value to
> society. See http://www.spnhc.org for membership information.
> Advertising on NH-COLL-L is inappropriate.