[Nhcoll-l] Telling formalin from ethanol

[Dirk Neumann]

Dear Megan,
you could use formaldehyde indicator strips whcih necessitates to open 
every jar. At least judging from our fish collection, formaldehyde 
stored specimens turn opaque over time and the fluid gets a yellowish 
tone (other than the yellowish-brown stained alcohol) because of the 
decalcification. (there are plenty his for "formaldehyde indicator strips")

You would need larger amounts of formaldehyde leaking from the specimens 
into the alcohol to be able to smell it (unless for formalin-sensitive 
people perhaps); another good option to recognise formaldehyde 
contaminations in alcohol is to check for thin paraformaldehyde needles 
/ precipitations at the bottom or floating in the fluid (easily 
detectable if you hold the jar against a lamp). This precipitation also 
froms if you transfer your specimens in an alcohol ladder (normally at 
the final step from 60 -> 70 % in packed jars with many specimens).

Hope this helps...
Dirk


Am 06.03.2014 15:31, schrieb Dietrich, Elizabeth:
> Telling formalin from ethanol
>
> Something to keep in mind-
>
> Based on our sampling, by chemical analysis, of fluids in tanks of 
> preserved animals, if the animals were fixed or previously preserved 
> in formalin there will always be a significant amount present in the 
> alcohol.  By significant, I don't mean by quantity but as a hazard.  I 
> would caution against doing much sniff testing.
>
> *From:*nhcoll-l-bounces at mailman.yale.edu 
> [mailto:nhcoll-l-bounces at mailman.yale.edu] *On Behalf Of *Best, Megan
> *Sent:* Thursday, March 06, 2014 9:03 AM
> *To:* nhcoll-l at mailman.yale.edu
> *Subject:* [Nhcoll-l] Telling formalin from ethanol
>
> Hello all,
>
> I've been benefitting from the conversations on this listserv for some 
> time now,really fascinating and useful stuff.I manage a research 
> collection, mostly of marine invertebrates, and I have a question:
>
> Is there an easy way to tell ifa fixative is formalin or ethanol? 
> Aside from the smell test!I'm looking to organisehundreds of jars from 
> various benthic surveys, and we want to switch out anything that's in 
> formalin to ethanol.  The formalin is buffered so I don't think a pH 
> difference would be a strong indicator.  Any ideas/advice would be 
> appreciated.
>
> -Megan
>
> *Megan Best*
> Invertebrate Taxonomy
> tel: 902.426.2791   email: megan.best at dfo-mpo.gc.ca 
> <mailto:megan.best at dfo-mpo.gc.ca>
> Ocean and Ecosystem Sciences Division | Division des sciences de 
> l'écosystème et de la mer
> Department of Fisheries and Oceans | Ministère des Pêches et Oceans
> Government of Canada | Government du Canada
> Bedford Institute of Oceanography | Institut Océanographique de Bedford
>
>
>
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-- 
Dirk Neumann

Tel: 089 / 8107-111
Fax: 089 / 8107-300
email: Dirk.Neumann(a)zsm.mwn.de

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Staatliche Naturwissenschaftliche Sammlungen Bayerns
Zoologische Staatssammlung München
Dirk Neumann, Sektion Ichthyologie / DNA-Labor
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81247 München

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---------

Dirk Neumann

Tel: +49-89-8107-111
Fax: +49-89-8107-300
email: Dirk.Neumann(a)zsm.mwn.de

postal address:

Bavarian Natural History Collections
The Bavarian State Collection of Zoology
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Muenchhausenstr. 21
81247 Munich (Germany)

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