I don't know how many of use cut plastic sections, but I have a question
regarding a Toluidine Blue stain solution:

1% Toluidine Blue O
1% Sodium Tetraborate Dodecahydrate
30% Ethanol
in DDI

I've been using this stain for years on Epon-Araldite sections and Durcupan
sections with no problems in getting satisfactory staining.  When I have
30-50mL remaining, I always make a new batch so it's ready the next time I
need it , but this time I forgot.  I made a new solution and had to use it
right away.  I stained my sections as usual, but the color of the sections
was bright blue instead of the more purple-blue we desire.  Thinking that
I'd made a mistake in preparing the solution, I made another batch and
decided to wait overnight to try it, but again the sections were bright
blue.

I was never aware of the need to do this, but does this solution need to
"ripen" for a week or so before using?  I can't think of any other reason.
The quality of our water hasn't changed, and everything else is the same as
I've always used.

Thank you for any help you can give me.

Jaclynn M. Lett, Research Technician
Electron Microscopy Core Facility
Fay and Carl Simons Center for Biology of Hearing and Deafness
Central Institute for the Deaf
4560 Clayton Ave.
St. Louis, MO 63110

jlett@cid.wustl.edu
314-977-0257