[NHCOLL-L:4539] RE: Question about Wet Collection

[Bentley, Andrew Charles]

Hi Ashley

Yes, your first course of action is to get rid of those Bakelite lids - they are terrible.  There are numerous suppliers of good alcohol resistant lids if you have not found one yet.  We use KOLS Containers and I would be happy to give you there details or to send you samples of various sizes if need be.  They should fit your existing jars.

As for the concentration problem, short of purchasing expensive equipment to determine actually concentration you could try the bead system developed by Alcomon.  Two plastic beads of different densities are placed in the alcohol and then float at different levels to give an indication of approximate concentration.  You can then adjust accordingly. http://www.alcomon.com.  I have some samples given to me the developer Dries van Dam if you would like to try them - or you may be able to get a sample from Dries.

In cases where there is very little fluid left or the fluid is badly discolored it may be wise to replace all fluid instead of trying to "make it up" to the correct concentration.

Hope that helps.  Let me know if you have any further questions.

Andy

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Andy Bentley
Ichthyology Collection Manager/Specify Usability Lead
University of Kansas
Natural History Museum & Biodiversity Research Center
Dyche Hall
1345 Jayhawk Boulevard
Lawrence, KS, 66045-7561
USA

Tel: (785) 864-3863
Fax: (785) 864-5335
Email: ABentley at ku.edu       
                                                
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-----Original Message-----
From: owner-nhcoll-l at lists.yale.edu [mailto:owner-nhcoll-l at lists.yale.edu] On Behalf Of Ashley Henderson
Sent: Wednesday, September 23, 2009 12:58 PM
To: NHCOLL-L at lists.yale.edu
Subject: [NHCOLL-L:4538] Question about Wet Collection

Hi Everyone,

I am looking for some advice about wet specimens.  I recently became
the Collection Manager at a museum with around 1,000 wet specimens.  My
experience with them is very limited.  I have read many articles
regarding their preservation, but I still have some how-to questions and
am seeking some advice.  The wet collection is mostly herpetology and
marine biology with some entomology.  They are in glass jars ranging in
size from a half gallon to small vials.  Most jars have plastic Bakelite
lids, which I have read allow for a great amount of evaporation.  Some
of the specimens are 30 to 40 years old and have been topped off
countless times.  Some of the jars have not been topped off recently and
are half empty.  So, I am dealing with a wet collection for which I have
no idea what the ethanol concentration is from jar to jar.  I would like
to work through the collection and bring each up to 70% ethanol.  From
my research, I understand that it is best to avoid completely changing
out the preservative.  What is the best way to test the preservative in
the jars so that I can then add the appropriate amount of ethanol to
establish a  70% level?  I have researched using hydrometers.  However,
many of the specimens in small jars do not have enough preservative to
remove a sample for testing.  What other methods are there and what
would be the best process for testing each of the specimens?  Or is it
even necessary?  Any advice would be greatly appreciated.

Thanks,



Ashley Henderson

Collection Manager
Corpus Christi Museum of Science and History
www.ccmuseum.com
(361) 826-4659