Para- or not-formaldehyde?

From: Unni Hadeland (Unni.Haddeland@hiak.no)
Date: Mon Jun 07 1999 - 12:27:52 EST


Para- or not-formaldehyde?

I`ve learned that when you dissolve 1g of solid paraformaldehyde in 10 ml PBS 
by extensively heating (boiling) and shaking you get 10% fresh paraformaldehyde
which at 4% is perfect for fixing cells for Flow cytometry if used whithin for 4
days, then you have to make a new fresh one. By reading the e-mails here, I
understand what I really have is hydrolysed paraformaldehyde, i.e. formaldehyde.
But will it be completely hydrolysed? Or do I have to by the solution of
formaldehyde containing 10-15% methanol? Or the methanol-free commercially
available formaldehyde? (Why is the commercially made "ultrapure" formaldehyde
fresh/unpolymerized for one year, whereas the home-made hydrolysed
paraformaldehyde (i.e. formaldehyde) is fresh for only 4 days?)

Thanks much!

Unni Haddeland
Research Laboratory
Akershus College
Ringstabekkvn 105
1365 Bekkestua
NORWAY



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