[Nhcoll-l] [Spam] Re: vials for storing insects in ETOH

[William Poly]

I've also observed the swelling of the green and gray rubber stoppers that
Doug mentioned.  The swelling is inside the vial where the stopper contacts
the ethanol.  Could be the denaturants reacting with the rubber (not sure
of the exact composition of these rubber stoppers).  Of course the entire
stopper will swell if immersed completely in a larger container.  Swelling
on both ends of the stopper could crack the neck of the vial[?].

As an alternate method of relieving pressure (instead of using hypodermic
needles), one can use a dissecting probe and release pressure on the side
of the rubber stopper (if the vials aren't too fragile); it's worked for me
and others.

Bill

*William J. Poly*

*Research Associate*

*Department of Ichthyology*

*California Academy of Sciences*

*55 Music Concourse Drive, Golden Gate Park*

*San Francisco, California 94118*

*wpoly at calacademy.org <wpoly at calacademy.org>*

*https://www.calacademy.org/scientists/ichthyology/wpoly
<https://www.calacademy.org/scientists/ichthyology/wpoly>*




On Thu, Nov 18, 2021 at 8:51 AM Callomon,Paul <prc44 at drexel.edu> wrote:

> Just some additional thoughts to what everyone else has said:
>
> - We have found that phenolic resin (the smooth, hard black resin used to
> make screw tops for smaller vials such as 4- or 6-dram ones, usually with
> foil or cone-seal liners) is not stable in ethanol; it leaches a brown
> stain into the fluid within a couple of years.
> - We use small glass "micro-vials" in our dry and wet collections. In
> alcohol, we stopper them with natural cotton wool. This is finer than
> polyester batting and thus less likely to snag the specimen; if the plug is
> made by first rolling the wool into a sausage and then folding it double
> and pushing the butt end into the vial opening (like a Kielbasa, extending
> the metaphor) there are few open fibers facing the specimen. Rehousing some
> 1850s lots recently gave me a chance to test the cotton for strength and
> confirmed that it is effectively inert in alcohol, though not in air. See
> https://avanan.url-protection.com/v1/url?o=https%3A//www.researchgate.net/publication/308079611_An_alternative_to_gelatin_capsules_in_natural_history_collections&g=ZjBjOTg5ZTY2Mzg2NGQzNQ==&h=ODY1ODc4MTRhYjY1NDYzOGY2YTdjODc1NzQxNjFjMDEzNGJlMGMwMmY5NWZiYjYzYzk1ZjI2N2YyMmM4N2ZmNQ==&p=YXAzOmNhbGFjYWRlbXk6YXZhbmFuOmc6OTJjMTkyY2QxYmNiNzk5MTU2NDk3ZGVjNzVhOTg4ZjU6djE6cA==
> Given that a vial is going to be submerged in ethanol, though, maybe one
> could use rolled paper as a stopper - perfectly stable, very cheap.
> Lollipop sticks (Chupa-chups and the like) are just rolled white paper, and
> expand slightly when wet - sliced up, they might make great micro-vial
> stoppers.
> - We used to keep multiple lots in common jars, as Tonya proposed, and
> still don't automatically counsel against it. There are economic advantages
> in terms of space and material costs and the time-saving element of only
> having to check one lid for dozens of specimens, but there might be
> long-term issues with sharing fluid via permeable internal barriers, such
> as the migration of lipids, radio-isotopes and even DNA between lots that
> could one day give a false signal in analysis. Placing multiple lots in a
> common jar but giving each one an impermeable stopper keeps them separate
> and means that the surrounding fluid is simply a secondary safety measure
> in case the internal stoppers fail. However, the stability in ethanol of
> any post-1980s plastic compound across museum-scale time periods is still
> not guaranteed.
>
>
> Paul Callomon
> Collection Manager, Malacology and General Invertebrates
>
> Academy of Natural Sciences of Drexel University
> 1900 Benjamin Franklin Parkway, Philadelphia PA 19103-1195, USA
> prc44 at drexel.edu Tel 215-405-5096 - Fax 215-299-1170
>
>
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