[Histonet] Schiff mystery

[Geoff McAuliffe]

There are several factors that influence the potency of Schiff's reagent.

The quality of the basic fushsin.
How much activated charcoal is used to decolorize the reagent. It is 
important to use the minimum amount that gives a clear (or almost clear) 
solution.
For the test, add a drop or two of Shiffs to formaldehyde, not the other 
way around.
And, as someone else mentioned, properly cleaned glassware.

Geoff

Lee & Peggy Wenk wrote:
> Need the help of the Histonet chemistry gurus.
>
> This has happened the last 2 times the students and I made up Schiff. Two
> different set of students.
>
> We make up the Schiff, and use it the next day, and it works correctly
> (stains the glycogen in liver and neutral mucins in intestine a bright
> magenta). Store in refrig. 1 week later, when we go to stain fungus with
> PAS, the Schiff doesn't work. Try the same liver and small intestine
> controls. Doesn't work at all. No magenta, no pink, nothing on the slides.
>
> When going into the water rinse after Schiff, the water turns pink with the
> newly made Schiff, but 1 week later, there is no color change in the water
> rinse.
>
> When we make up the Schiff, we show the students the Schiff quality
> assessment, where we put a few drops of formaldehyde in it, and the Schiff
> changes to purple immediately. Works great newly made. One week later, when
> we can't get the Schiff to stain, there is no color change with
> formaldehyde. None.
>
> It is the same procedure we've been using for years to make up the Schiff.
> It is the same procedure our histology lab uses. Their Shiff lasts for
> months. Ours last for a few days.
>
> I think it might be one of our reagents is going bad. Histology lab has
> their own reagents, the School has our own. 
> - The basic fuchsin is OK, as the Kinyoun works great.
> - The hydrochloric acid was taken from histology, so I'm guessing it's OK.
> - The charcoal is fairly new. Could that be the problem? Why?
> - We are using sodium metabisulfite, not sodium sulfite or sulfate. At least
> that's what the bottle says. Does this break down and go bad?
>
> Need all the help we can get. This is spooky, Halloween or no Halloween.
>
> Peggy Wenk, HTL(ASCP)SLS
> Schools of Histotechnology
> Beaumont Hospital
> Royal Oak, MI 48073
>
>
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>
>   


-- 
--
**********************************************
Geoff McAuliffe, Ph.D.
Neuroscience and Cell Biology
Robert Wood Johnson Medical School
675 Hoes Lane, Piscataway, NJ 08854
voice: (732)-235-4583 
mcauliff <@t> umdnj.edu
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