[Histonet] Tris Buffer Preservative

[Amos Brooks]

Hi,
   I have been making up my own tris buffer for immunohistochemistry. It has
been working swimmingly, with one exception. I have been doing some work on
Salmonella, and apparently the researcher has been seeing bacteria in her
immunofluorescent slides that she says are moving and seem to be viable. She
wanted to culture all my reagents. So the primary and secondary antibody
diluents (commercially purchased) came up clean, but the TBS ended up with a
pretty healthy growing colony. Now since I don't do IHC overnight in an
incubator, I don't think this is necessarily a catastrophy. (No one else has
noticed this) It does seem to warrant further investigation though. So for
the folks that make their own solutions up, what do you use as a
preservative for your buffers and how much do you use. I haven't seen
anything in any of the recipes I have found. I was thinking Sodium Azide,
but it is really hazardous, and Wikipedia says it is actually explosive (
http://en.wikipedia.org/wiki/Sodium_azide). Biocare Medical's data sheet
says they use less than 0.25% procyclin. (thanks for not hiding the
ingredients Biocare, I love you for that!) Has anyone tried that? Any other
suggestions would be welcome.

Thanks,
Amos