[NHCOLL-L:5739] Re: fluid preservatives

[A.J.van_Dam at lumc.nl]

Dear Carolyn,

The safest and most reliable alternative to use is the alcohol "glycerol" in an end concentration of 65%, in use in our collections for about 100 years.

DMDMH, a formaldehyde releasing agent (used as low toxic alternative in cosmetic and personal care products), could also be an alternative but like Novec there is not yet a long track record. Know that the very expensive Novec does NOT replace the (hazardous) preservative inside the tissue, it should be seen as liquid embedding media / envelope fluid, like liquid paraffin.

Glycerol has extreme low vapor pressure, is low toxic (same NFPA health hazard rating as ethanol), flash point of 160 degrees Celsius (ethanol 13 degrees Celsius), preserves/revives (blood) color, no shrinkage when transferred in baths of increasing glycerol concentration.

Of interest might be our recently published paper (preprint of the Triennial Conference of ICOM-CC 2011, Lisbon):

A migration mechanism for transfer of sharks from ethanol to aqueous glycerol solutions

Ian D. MacLeod*
Western Australian Museum
Collections & Research Centre
Welshpool, Western Australia, Australia
ian.macleod at museum.wa.gov.au

Andries J. van Dam
Leiden Museum of Anatomy
Leiden University Medical Centre
Leiden, The Netherlands
*Author for correspondence

Abstract
This paper presents a scoping study on the impregnation of glycerol into formaldehyde-fixed and aqueous-ethanol-preserved sharks. The weight increase and solution density changes were monitored in sequential baths of aqueous glycerol. Positive results included a return of the colour of the specimens, improved flexibility, and removal of alcohol from the body of the specimen and significant improvement of the original profiles and skin textures of the specimens.

Regards,

Dries


Andries J. van Dam, conservator

Museum of Anatomy
Leiden University Medical Center
Postal zone T7-P
P.O.Box 9600
2300 RC Leiden
The Netherlands
tel: +31 (0)71 526 9581
fax: +31 (0)71 526 8275
E-mail: A.J.van_Dam at lumc.nl
Visiting address: Hippocratespad 21, building 3



Associate scientist, Natural History Museum, London
http://www.nhm.ac.uk<http://www.nhm.ac.uk/>


Directory Board member ICOM-CC
http://www.icom-cc.org<http://www.icom-cc.org/>

Director Alcomon Company
http://www.alcomon.com<http://www.alcomon.com/>


________________________________
From: owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Couteaufin at aol.com
Sent: dinsdag 29 november 2011 23:59
To: crissanen at museumca.org
Cc: nhcoll-l at lists.yale.edu
Subject: [NHCOLL-L:5738] Re: fluid preservatives

Hi Carolyn,

I have never had firsthand experience with Novec, but it is an expensive fluid and has a high specific gravity so specimens float in it.  It has not been tested in the long term and I have a bad feeling about it.

Have you considered an alternative such as Dekafald (DMDM hydantoin)?  It acts as an ionic transfer agent using methylene bridges like formalin?

It also depends on what specimens are intended for display (vertebrate, invert, botanical &c)?  Glycol preservatives are still good in the short term (1 year or so) if the specimens have been properly fixed beforehand.

Also need to know what type of jars would be involved (glass, plastic)?

With all good wishes, Simon

Simon Moore MIScT, FLS, ACR,
Conservator of Natural Sciences,
20 Newbury Street,
Whitchurch RG28 7DN. UK
T. 01256 892335
www.natural-history-conservation.com<http://www.natural-history-conservation.co.uk/>

www.pocket-fruit-knives.info <http://www.pocket.fruit-knives.com/>

In a message dated 29/11/2011 00:13:09 GMT Standard Time, crissanen at museumca.org writes:
Dear list -
We are in the midst of a major gallery re-install, and there has been some discussion about putting wet specimens out as part of one of the new exhibits.  The question came up about whether there was a safer alternative to de-natured alcohol or formalin as a preservative - a fluid that wouldn't be quite as hazardous should something happen to the jar.  Doing a web search, someone came up with a 3M product: 3M Novec Engineered Fluid.  Does anyone have any experience with this product?  Do you have any advice concerning display of fluid preserved specimens?

Thanks,
Carolyn
Carolyn Rissanen
Registrar, Collections and Information Access
Oakland Museum of California
www.museumca.org<http://www.museumca.org/>
510-318-8490


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.yale.edu/mailman/private/nhcoll-l/attachments/20111130/a5839e40/attachment.html