RE: ethyl or reagent alcohol?
Fred, and all,
Reagent alcohol bought by hisology labs is a blend of ethanol, methanol and
isopropanol, and works fine as 100 percent "alcohol" (A catalog here has
"reagent alcohol" as a blend of 90 percent absolute ethanol, 5% methanol,
and 5%isopropanol). In my experience I have not seen any functional
difference in general histology (processing, routine staining,
deparaffinizing) using either "reagent" alcohol or anhydrous ethanol as 100
The difference is that if you get 100 percent ethanol you have to pay
federal tax (unless you get an expemption). The aldrich catalog shows 4L of
ACS 200 proof ethanol to be twice the cost (with tax)of 4L of reagent
From: Monson, Frederick C. [mailto:firstname.lastname@example.org]
Sent: Friday, January 24, 2003 10:35 AM
To: List-HistoPath (E-mail)
Subject: FW: ethyl or reagent alcohol?
Before I launch on this mini-diatribe, I want to make clear that Martin's
question is quite legit. However, I think it has been already misread, and
since I think I have it right, here goes.
OK, I don't know anything about the recycling methods used by the common
recyclers used in histo labs, but before the question about "ethyl" and/or
"reagent" alcohols goes any further, I want to see if I have missed
Now I took organic chemistry in 1964, so I may be cloistered in a closet of
ethyl alcohol is ethanol is 1-hydroxy-ethane
"reagent" is a term used to characterize either a mixture or the
quality of a substance. One would think that "reagent" would only be used
to characterize unadulterated formulations, but I have seen it used in
instances where the ethanol has been diluted and THEN denatured.
"reagent ethanol" is almost always 95% ethanol + 5% water.
Now to my revisions of Martin's question.
If one recycles ethanol, does one get, as a result, "absolute
ethanol" (200 Proof, 100%, USP) or does one get 95+or-% ethanol back? Does
one use absolute ethanol for final dehydrations or does one use 95% for
If one is not recycling ethanol, would one choose absolute ethanol
as a starting point for all dilutions or would one choose 95% ethanol (one
of the "reagent" alcohols)?
Finally I should like to respond to my interpretations as follows.
The word "mouse" is irrelevant to this discussion - in my thinking.
I always use absolute ethanol (USP) that I have purchased in PINT
packages, because as soon as I open a container, the ethanol rapidly becomes
less than absolute. This has been true when I use it in any histology, any
chemistry, any biochemistry, and any molecular biology, and any parties.
I always use 95% ethanol ("reagent" alcohol) to fabricate other
concentrations of ethanol. I personally INSURE that none of the "reagent
ethanol I purchase is denatured.
I have never recycled ethanol, because I have never operated in an
environment in which that would be cost effective, so I defer to others in
matters specific to those applications.
Frederick C. Monson, PhD
Center for Advanced Scientific Imaging
Mail to Geology
West Chester University of Pennsylvania
Schmucker II Science Center, Room SS024
South Church Street and Rosedale Avenue
West Chester, PA, 19383
An FEI (Quanta 400 and Technai 12),
Oxford INCA Energy 400, and
Olympus FV-300 Shop.
From: Martin, Ronald [mailto:Ronald.Martin@umassmed.edu]
Sent: Friday, January 24, 2003 8:15 AM
Subject: ethyl or reagent alcohol?
I have a question for those of you involved in research with mouse tissue.
Which type of alcohol do you prefer for your tissue processing, ethyl
alcohol or reagent alcohol?
Ron Martin, B.Sc., HTL (ASCP)HT
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