[Histonet] toluidin blue

[Jay Lundgren]

 IMHO, Borax ain't that dangerous, my Granny put it in her laundry.
However...

Toluidine Blue is basic, it stains acidic tissue components.  It will stain
differently at different pHs.  It gives increased metachromatic staining at
pH 4. What pH buffer system are you looking for?

Sodium phosphate, monobasic 4.0 gm, Sodium phosphate, dibasic 6.5 gm, qs to
1L with diH2O gives pH 6.8.

Ammonia solution and ammonium chloride in equal molar concentration gives
you pH 9.25.  Though if they won't let you play with borax, they probably
won't let you play with ammonia.

Ethanoic acid and sodium ethanoate in equal molar concentration gives you
pH 4.76.  They probably don't want you handling glacial acetic acid either.

If you want to get fancy, make McIlvaine buffer, any pH you want from 2.2
to 8 by mixing 2 stock solutions of disodium phosphate and citric acid.
You could do a range, and let the pathologist pick their favorite staining.
Both are common food additives, so safe, unless you rub them in your eyes.
Wikipedia has a table.

I don't have to tell you that for any new protocol, you should run 15-20
independent controls.  Cartilage or bone marrow is a good control for
Toluidine Blue.

Beware of moose, a moose once bit my sister,

Jay A. Lundgren, M.S., HTL (ASCP)





On Mon, Aug 12, 2024 at 6:26 AM Tora Bardal via Histonet <
histonet at lists.utsouthwestern.edu> wrote:

> To all the good histochemist/ chemists ...
>
> I usually make up toluidine blue for staining Epon and Technovit in borate
> buffer, 1 % konc.
> Due to HSE I'm interested in substituting the  sodium borate buffer with
> another buffer.
> Any knowledge out there?? Recommendations?
>
> Tora
>
> Tora Bardal
> Senior Engineer
> NTNU Sealab
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