Re: ethyl or reagent alcohol?

From:Mark Ray


I remember having addressed this subject before,  but I will reiterate just
for the heck of it.  The term Reagent Alcohol is a controlled appellation of
the Department of Alcohol, Tobacco and Firearms of the US Treasury.

Any product labelled Reagent Alcohol must contain what Tim describes, about
90% ethanol, 5% methanol and 5% isopropanol. Manufacturers may not label a
product Reagent Alcohol which contains ANY other denaturant, PERIOD.  It's
the law.  Check the ATF website.   There may be some products on the market
in violation of this regulation.  Don't ask me how they get away with it.
However, if you check the label of most reagent alcohols, you will see that
they are in compliance.

Mark Ray
EK Industries

----- Original Message -----
From: "Morken, Tim" 
To: "'Histonet'" 
Sent: Friday, January 24, 2003 11:11 AM
Subject: RE: ethyl or reagent alcohol?

> Fred, and all,
> Reagent alcohol bought by hisology labs is a blend of ethanol, methanol
> 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
> percent "alcohol."
> 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
> ACS 200 proof ethanol to be twice the cost (with tax)of 4L of reagent
> alcohol.
> Tim Morken
> Atlanta
> -----Original Message-----
> From: Monson, Frederick C. []
> 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,
> 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
> something.
> Now I took organic chemistry in 1964, so I may be cloistered in a closet
> ignorance, but....
> 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?
> one use absolute ethanol for final dehydrations or does one use 95% for
> everything?
> 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
> less than absolute.  This has been true when I use it in any histology,
> 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.
> Regards,
> Fred Monson
> 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
> Phone:  610-738-0437
> eMail:
> An FEI (Quanta 400 and Technai 12),
> Oxford INCA Energy 400, and
> Olympus FV-300 Shop.
> -----Original Message-----
> From: Martin, Ronald []
> Sent: Friday, January 24, 2003 8:15 AM
> To:
> Subject: ethyl or reagent alcohol?
> Histonetters,
> 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?
> Thanks,
> Ron Martin, B.Sc.,  HTL (ASCP)HT
> Research Associate

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