[Histonet] Re: Buffer.

Robert Richmond RSRICHMOND <@t> aol.com
Sun Nov 16 13:12:09 CST 2008

About the potential toxicity of arsenic-containing cacodylate buffers:

A Histonetter who prefers to remain anonymous notes >>The arsenic
discussion comes up on the Microscopy Listserver every once in while,
usually because someone is either pregnant & concerned about exposure
or has safety officers who freak out over the stuff. It was used in
the early days because phosphate buffers can interact with some of the
fixative combinations and leave precipitates. Also, I'd suspect,
cacodylate is less prone to beasties growing in stock solutions over
time. The "modern" zwitterionic buffers are used a lot these days -
PIPES & that crowd - if you want to avoid cacodylate & phosphate.<<

Those zwitterionic buffers are often referred to as Good's buffers or
Good buffers, since they were introduced by Norman Good in the 1960's.

I don't know why they aren't commonly used as buffers for histologic fixatives.

Bob Richmond
Samurai Pathologist
Knoxville TN

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