Alternatives to Formalin/Formaldehyde?
J. A. Kiernan
jkiernan at julian.uwo.ca
Mon Mar 27 09:50:23 EST 1995
In article <eeeD61327.GyB at netcom.com> eee at netcom.com (Mark Thorson) writes:
>From: eee at netcom.com (Mark Thorson)
>Subject: Re: Alternatives to Formalin/Formaldehyde?
>Date: Sun, 26 Mar 1995 03:30:07 GMT
>What's the difference between formalin and formaldehyde? I've read
>that formalin is commonly used for chemical sterilization of food
Formaldehyde = HCHO (a gas)
Formalin = 37-40% w/w HCHO in water. Actually consists
largely of methylene hydrate and low polymers.
Some methanol is added in manufacture, to
Paraformaldehyde = solid high polymer of HCHO. Depolymerizes as it
dissolves (typically in a physiological buffer; won't
dissolve in pure water) at 60C. Used as a source of
methanol-free formaldehyde (methylene hydrate),
especially in fixatives for electron microscopy.
John A. Kiernan
Department of Anatomy
Univ. of Western Ontario
LONDON, Canada N6A 5C1
e-mail: jkiernan at julian.uwo.ca
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