Re: substituting HCl for Picric acid

From:"J. A. Kiernan"

Foolishly, I didn't look in Ruzin even though it's
on the shelf!  I've looked now. He describes a
differentiation of the safranine in 95% alcohol
containing 5% picric acid. This will work in
much the same way as acid-alcohol used to differentiate
an alum-haematoxylin, so it should be OK to substitute
hydrochloric acid. Ruzin mentions this in the preamble
to the method but doesn't give a concentration. I
suggest 0.5 ml of conc.HCl per 100 ml of alcohol.
Make it weaker if this extracts safranine too quickly.

I have done safranine-fast green FCF using just
water and alcohol for the differentiation. It's
quite easy to remove too much safranine. With an
acid-alcohol differentiation it will probablly be
even easier. In Ruzin's procedure the differentiation
is abruptly stopped by transferring the slides
to alkaline alcohol. He also warns about the dye 
being extractable by alcohol alone. 
-- 
-------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan/
_______________________________________________
abishop@sfsu.edu wrote:
> 
> I am using a protocol from Ruzin's Plant Microtechnique book. I'm not sure
> if this technique is common but it does involve picric acid. I believe
> that the
> picric acid stops the safranin from overstaining.
> 
> A. Bishop
> San Francisco State University
> 
> On Thu, 19 Dec 2002 12:35:27 -0500 "J. A. Kiernan" wrote:
> 
> > I've looked in a few books and cannot find a variant
> > of Johansen's safranine-light green (or -fast green FCF)
> > that involves picric acid. Is your technique something
> > other than the commonly used stain for sections of
> > plant tissue?  (The same combination of dyes has been
> > used for cytoplasmic organelles in sections of
> > osmium-fixed animal material, but I don't think it
> > has a big following for that purpose these days.)
> > --
> > -------------------------
> > John A. Kiernan
> > Department of Anatomy and Cell Biology
> > The University of Western Ontario
> > London,   Canada   N6A 5C1
> >    kiernan@uwo.ca
> >    http://publish.uwo.ca/~jkiernan/
> > ------------------------------------------
> > abishop@sfsu.edu wrote:
> > >
> > > Has anyone out there ever used HCl as a substitute for Picric acid in a
> > > staining protocol such as Johansen's Safranin/Fast Green? If so
> > what were
> > > the results? Thanks for reading this.
> > >
> > > A. Bishop
> > > San Francisco State University
> > > 1600 Holloway Ave
> > > San Franicso, CA 94132
> >
-- 
-------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan/



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