[Nhcoll-l] vials for storing insects in ETOH

[Douglas Yanega]

To some degree, this may depend on how often you foresee vials needing 
to be opened.

Case in point: we have a massive collection of the immature stages of 
insects, numbering nearly 10,000 vials. For decades, the former curator 
had to keep topping off these vials because of ethanol evaporation. In 
all those decades, apparently only one person had ever made use of any 
of the specimens in that collection besides the professor who had built 
that collection as his personal research project.

So, what we did was to buy several thousand hospital-grade Vacutainer 
serum glass test tubes with red rubber "injection port" stoppers, 
designed to be used by hypodermic puncture of the stopper. It turns out 
that the little 1-dram shell vials that we already had in stock by the 
tens of thousands (and a few larger sizes of shell vials) are *the exact 
same diameter* as these standard blood sample test tubes, and those 
stoppers fit perfectly. We removed the stoppers from the test tubes, 
transferred all of the contents of the old vials into shell vials, and 
put the stoppers in by inserting a hypodermic needle in the cap to 
release the pressure and then sealing the vials. While this did leave us 
with thousands and thousands of useless test tubes, it was - for 
whatever odd reason - *significantly* cheaper to buy test tubes with 
stoppers in them than it was to just buy the exact same stoppers in 
bulk. At the time, I think it was only about 15 dollars per 100 test 
tubes, and about 50 cents per stopper. Looking online now, those 
stoppers appear to sell for 85 cents each, and the Vacutainer tubes with 
those exact stoppers are 35 dollars per 100. Go figure.

That was 15 years ago now, and the stoppers are in perfect shape, and we 
haven't lost a milliliter of ethanol, cumulative - except for the two or 
three vials that have been opened in those 15 years. I would rate this 
as an incredible success, with the one qualification being that you 
can't put the stoppers back without using a hypodermic needle to release 
the pressure. That's why, for a very actively-used collection, this 
approach might create some real headaches.

The old neoprene stoppers (we had black ones, green ones, and gray ones) 
all seemed to swell up or even dissolve from prolonged contact with 
ethanol, but these red ones show no signs of any problems to date, and 
maybe they are actually archival. It may take another 25 years or so to 
be certain. Regardless, we have no more vials with neoprene stoppers or 
plastic stoppers. More heavily-used parts of our collections that are 
kept at room temperature utilize either the "many vials inside a bigger 
vial" system that many people practice, or use screw-cap vials with 
cone-shaped plastic cap inserts that drastically reduce evaporation. We 
use different storage systems for ethanol samples kept in the freezer, 
and evaporation isn't an issue.

I don't have all of the specs and supplier and manufacturer data handy, 
but anyone seriously interested should not have too much difficulty 
figuring out how to do the same thing we did.

Peace,

-- 
Doug Yanega      Dept. of Entomology       Entomology Research Museum
Univ. of California, Riverside, CA 92521-0314     skype: dyanega
phone: (951) 827-4315 (disclaimer: opinions are mine, not UCR's)
              https://faculty.ucr.edu/~heraty/yanega.html
   "There are some enterprises in which a careful disorderliness
         is the true method" - Herman Melville, Moby Dick, Chap. 82
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