Rita Angel writes:
        Our lab has been having a problem lately with our Masson's
Trichrome.... Our muscle has been staining purple instead of red.... and
we were purchasing the Gomori's stain pre-made.

Rita

The red dyes in trichromes are to some extent interchangeable. Here in
the UK, where Masson's is favourite, the older methods used a mixture of
dyes whereas the new ones use straight acid fuchsin. This results in a
much more purple coloration of muscle.

My guess would be that your supplier has changed the brew and is now
using acid fuchsin instead of chromotrope 2R.

Good luck!
--
Jim Elsam
HTEQA Services