[Nhcoll-l] Mixing EtOH

[Bentley, Andrew Charles]

Hi Tonya

We usually bubble air through our alcohol while mixing which seems to do a better job of mixing that simply rolling or inverting (although we have never used a paddle).  We have not seen any later separation of the fluid.  We use a hose off our lab air supply with a metal end that sinks it down to the bottom of the fluid.  We usually let is bubble for a couple of hours after filling the 25 liter carboy with 95% ethanol and deionized water to dilute to 70%.

Andy
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Andy Bentley
Ichthyology Collection Manager
University of Kansas
Biodiversity Institute
Dyche Hall
1345 Jayhawk Boulevard<x-apple-data-detectors://9/>
Lawrence, KS, 66045-7561<x-apple-data-detectors://9/>
USA<x-apple-data-detectors://9/>

Tel: (785) 864-3863<tel:%28785%29%20864-3863>
Fax: (785) 864-5335<tel:%28785%29%20864-5335>
Email: abentley at ku.edu<mailto:abentley at ku.edu>
ORCID: https://orcid.org/0000-0002-3093-1258
http://ichthyology.biodiversity.ku.edu<http://ichthyology.biodiversity.ku.edu/>
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From: Nhcoll-l <nhcoll-l-bounces at mailman.yale.edu> On Behalf Of Haff, Tonya (NCMI, Crace)
Sent: Tuesday, September 6, 2022 8:40 PM
To: nhcoll-l at mailman.yale.edu
Subject: [Nhcoll-l] Mixing EtOH

Hello all,

I have a question about mixing storage strength (70%) undenatured EtOH. Typically we add the correct proportions of 95% EtOH and water to a container and paddle or invert the container repeatedly to mix the liquids, and allow it to sit for ~24+ hrs. The containers we like best to use for dispensing 70% EtOH are 20L plastic water containers with a tap at the bottom. Recently we used our digital alcohol meter to test the alcohol concentration from the top and bottom (tap) of one of these containers and found the alcohol concentrations wildly different  - ~80% at the top and ~60% at the bottom - despite having been mixed more than 24 hours earlier. This makes me really concerned that we could be regularly using concentrations that are much above 70% with specimens. I wonder if any of you have had a similar problem, or if anyone can suggest a solution? Is there a better way of mixing or of ensuring the solution is properly combined? Any thoughts appreciated.


Thank you!

Cheers,

Tonya
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Dr. Tonya M. Haff
Collection Manager
Australian National Wildlife Collection
CSIRO
+61(0)419569109
https://www.csiro.au/en/about/facilities-collections/collections/anwc<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.csiro.au%2Fen%2Fabout%2Ffacilities-collections%2Fcollections%2Fanwc&data=05%7C01%7Cabentley%40ku.edu%7C276b9a5b244d47fb5d9608da9071dd16%7C3c176536afe643f5b96636feabbe3c1a%7C0%7C0%7C637981116138572332%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=y37Qrzo1w9Ar709zZeQ7VwPrjD%2BZnE8W1zK8SN9xfVY%3D&reserved=0>

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