SUBJECT: Recipe for buffered formalin
DATE: 2/97
 
Hi labbers- Could someone tell me how to make neutral buffered formalin?
Thanks. Mary
 
Mary H. Gray D.V.M.
Department of Biological Sciences
Lilly Hall of Life Science
Purdue University
West Lafayette, IN 47907
(765)-494-8185
FAX (765)-494-0876
 
 
Hope this is useful
 
Neutral Buffered Formalin (pH 7.0)
 
Formalin, full strenghth (37-40% formaldehyde) 100.0 ml
Sodium phosphate dibasic (anhydrous) 6.5 gr
Sodium phosphate monobasic 4.0 gr
Distilled water 900 ml
 
from "A Manual of Histotechniques" 3rd ed. Ann Preece, 1972. An old text but
I doubt if the formula has changed any.
 
Al
 
 
% Al Williams AAWilliams@Manchester.edu
% Biology Department Voice 219-982-5308
% Manchester College FAX 219-982-5043
% N. Manchester, IN 46962
 
 
 
Mary,
 
I use the following recipe to prepare formaldehyde from paraformaldehyde for
fixing mammalian cells for immunofluorescence studies:
 
1. Heat 15 mls of PBS (phosphate buffered saline, pH 7.2)(see below for PBS
recipe) to about 55 degrees C.
 
2. With stirring, add 0.75 grams paraformaldehyde to the PBS.
 
3. Add, dropwise, 0.1 N NaOH (the combination of heat and NaOH breaks the
paraformadehyde polymer into formaldehyde molecules) just until the solution
becomes completely clear.
 
4. Let cool and adjust the pH to desired value.
 
5. Add an additional 10 mls of PBS.
 
PBS recipe (I need to use a Mg- and Ca-free variety):
-----------------------------------------------------
KCl 0.2 grams
KH2PO4 0.2
NaCl 8.0
Na2HPO4*7H2O) 2.16
 
Final volume to 1L with distilled water.
-----------------------------------------------------
 
Hope this helps. Good luck.
 
George
 
George Edick
RPI - Dept. Biology
Troy, NY 12180
edickg@rpi.edu
 
 
 
The recipe for buffered formalin from Humason is:
 
10% formalin (stock is 37%) 1000 ml
NaH2PO4.H2O 4 g
Na2HPO4 6.5g
 
May remain in fixative indefinitely. Action is progressive
 
From: greggk@winthrop.edu
 

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