From:Lee & Peggy Wenk <>

Yesterday, one of my students did a PAS and PAS digestion. NOTHING in the
glycogen control (liver loaded with glycogen) stained PAS +, including the
reticulin and connective tissue.

I did the quality of Schiff reagent test but adding some formaldehyde to
some Schiff, and it turned dark purple immediately. So my original thought
was that her new Schiff was OK.

So I had her make up some new periodic acid, as the solution she made up was
the last of a bottle, so I thought that might be the problem. So we made up
new periodic acid, put the same slides in the new periodic acid, then back
in her new Schiffs, and still nothing worked.

After much digging around, I found out that the student had made the Schiff
with conc. HCl, not 1 N HCl.

So, I'm curious. What DID she make? Why DIDN'T it stain anything?

We then went and borrowed some Schiff from another lab, and restained the
same tissues. The stain worked, but was much lighter in color than usual.
Would that much extra HCl remove glycogen?

Just my curiosity at work. Thanks for any input.

Peggy A. Wenk, HTL(ASCP)
William Beaumont Hospital
Royal Oak, MI 48073

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