[Nhcoll-l] Fluid preservation jar lids

[Callomon,Paul]

I agree with Rob; we could not find any account of cotton deteriorating in ethanol, nor any chemical reason why it should. We have used it as an internal divider in shared containers for more than a century. The problem of picking up spines can be partially mitigated by tightly rolling the cotton into a sausage, then bending it double and sticking the doubled end into the vial and ; that way, the part facing the specimen is a smooth wall of curved fibers, not an open brush.



Paul Callomon
Collection Manager, Malacology and General Invertebrates
________________________________
Academy of Natural Sciences of Drexel University, Philadelphia
callomon at ansp.org Tel 215-405-5096 - Fax 215-299-1170

________________________________
From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> on behalf of Robert Waller <rw at protectheritage.com>
Sent: Tuesday, August 16, 2022 7:25 PM
To: nhcoll-l at mailman.yale.edu <nhcoll-l at mailman.yale.edu>
Subject: Re: [Nhcoll-l] Fluid preservation jar lids


External.

Our field has conflated the idea of wood products becoming acidic over time with pure cotton (cellulose) becoming acidic over time. It is the lignin content of wood that becomes acidic, and in some cases additives to paper, that become acidic over time (through oxidation and/or hydrolysis). Pure cotton itself is not expected to become acidic over time except by transfer of acidity from adjacent components and even that is questionable. Certainly, in fluid preserved collections there are many components that will react with oxygen before cellulose gets a chance. These include residual formaldehyde from fixation, oils, fats, and other organic constituents  from specimens, and even ethanol itself – consider the wine into vinegar process.

Pure cotton presents no risk of acidification, although it may present problems of catching on complex surfaces.

Rob



lete saatja õigsuses ja sisu turvalisuses kindel.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.yale.edu/pipermail/nhcoll-l/attachments/20220817/fb7da494/attachment.html>