[Histonet] formalin-formula and osmolarity

From:"Gudrun Lang"

Hi all,

I need the help of those with a talent in chemical calculation.

This formula is used in our institute since 1970, but nobody knows the
origin or a publication.


Formalin-formula: 8% buffered Formaldehyd

2 Liter 36% Formaldehyd

2 Liter Phosphatpuffer pH 7,8

6 Liter Aqua dest.

EndpH 7,4


commercial Phosphatpuffer contents:

Natrium di-hydrogenphosphat monohydrat          1,810 g 

di-Natrium monohydrogenphosphat dihydrat        3,756 g 

Natriumchlorid                                                  4,4 g 

Water                                                             ad  1000


Phosphatebuffer has a molarity of  34,2 mmol/l.


Can anybody calculate the osmolarity of the ready formalin-solution for me? 

What could be the advantages or disadvantages compared to Lillies 4% NBF or
Carson's 4% NBF?

Is the buffer-effect big enough in comparison to other formulas with 0,1 M


Pleas help, any input is appreciated.

Gudrun Lang


Linz, Austria




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