[Nhcoll-l] Telling formalin from ethanol

[Kate Pocklington]

Hey Megan,

If you're looking for a long-term solution you could invest in a density meter. We have one here in Singapore and I used one in my previous job at Oxford University with over 6000 jars - it definitely speeds things up!
It's useful to have one for identifying between formalin and alcohol and also for checking the percentage of the preservative.
They are quite pricey but they're worth it in the long run http://www.anton-paar.com/corp-en/products/details/portable-density-meter-dma-35/

Cheers!
Kate

From: nhcoll-l-bounces at mailman.yale.edu [mailto:nhcoll-l-bounces at mailman.yale.edu] On Behalf Of Morris, Robert (SAM)
Sent: 07 March 2014 07:27
To: Best, Megan; nhcoll-l at mailman.yale.edu
Subject: Re: [Nhcoll-l] Telling formalin from ethanol

Hi Megan,

When upgrading our sprit stores some years ago now, we were required to separate our collections stored in alcohol from those stored in Formalin for fire and safety compliance reasons. In short a fire in an alcohol store is a hazard but a fire in a store with formalin is a toxic hazard. This was a huge undertaking given the size of our spirit collections so we had to find a quick and simple testing procedure.

A range of techniques was tested including differing light properties, pH, specific test strips, reactive paper as well as the use of a hydrometer. These techniques were dismissed either due to the inefficiency of the system or the relative costs involved. After a short time, it was brought to light that a method employing a pipette with an ampulla containing a float (plastic pinhead) had been used in the Australian Museum for the same purpose.  It was difficult to replicate this equipment exactly but we found that a 5 cc syringe with a pinhead inside served exactly the same function but was both faster and easier. This method worked with 100% success in differentiating between the two solutions and was therefore adopted as the preferred method of sampling for all collections.

We could not sample every specimen jar so we selected the most likely groups that were stored in formalin, such as soft bodied animals, and fully tested them. For the rest we sampled statistically to confirm likely makeup.

Best of luck

Robert Morris
Head of Collections
South Australian Museum
North Terrace, Adelaide SA 5000
P: +61 (8) 8207 7455
robert.morris at samuseum.sa.gov.au<mailto:robert.morris at samuseum.sa.gov.au>
www.samuseum.sa.gov.au<http://www.samuseum.sa.gov.au/>


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From: nhcoll-l-bounces at mailman.yale.edu<mailto:nhcoll-l-bounces at mailman.yale.edu> [mailto:nhcoll-l-bounces at mailman.yale.edu] On Behalf Of Best, Megan
Sent: Friday, 7 March 2014 12:33 AM
To: nhcoll-l at mailman.yale.edu<mailto: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 if a fixative is formalin or ethanol?  Aside from the smell test!  I'm looking to organise hundreds 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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