[NHCOLL-L:5741] Re: fluid preservatives

Wed Nov 30 13:56:54 EST 2011

Please excuse my ignorance as a list lurker.

Can someone elaborate on the danger of keeping specimens in ethyl alcohol?
Am I correct in assuming this is safer by far than formalin?

Would there be much of an advantage to changing over to glycerol for use in
a nature center setting? Our specimens are common items, and part of a
teaching collection only - therefore not necessarily requiring the same kind
of preservation as in a museum setting. They were initially preserved in
formalin, then placed in ethyl alcohol. Loss of color doesn't seem to be
much of an issue.

Thanks for any input.

Sue

********************************************************

Susan Gallagher, Chief Naturalist

Carbon County Environmental Education Center

151 East White Bear Drive

Summit Hill, Pennsylvania, 18250

(570) 645-8597

www.carboneec.org

Teaching a child not to step on a caterpillar is as important to the child,
as it is to the caterpillar.

- Bradley Miller

.

From: owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu]
On Behalf Of A.J.van_Dam at lumc.nl
Sent: Wednesday, November 30, 2011 5:37 AM
To: Couteaufin at aol.com; crissanen at museumca.org
Cc: nhcoll-l at lists.yale.edu
Subject: [NHCOLL-L:5739] Re: fluid preservatives

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,
im-proved flexibility, and removal of alcohol from the body of the specimen
and signifi-cant 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
 <http://www.museumca.org/> www.museumca.org
510-318-8490

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