[Histonet] tissue fixation-formaldehyde concentrations which is best.

[Peter Noyce]

Formaldehyde 37% (commonly called 100% formalin) compared to 4% ( commonly
known as 10% neutral buffered formalin)-in theory the 37% should fix quicker
and better BUT anecdotally it is said that high concentrations of
formaldehyde quickly form a "shell" in the tissue and will stop good
penetration and fixation to the deeper tissues AND over the years it has
been said anecdotally that 4%  concentration is the quickest and most
complete for all sample (mammal and plant) fixation and preservation-are
these true. Please do discuss the methanol or buffers that is in the
formaldehyde, or discuss paraformaldehyde (which is non polymerized
formaldehyde with no methanol, in water).

Regards Peter Noyce PhD student.