RE:pH paper vs. meter

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From:Dana Settembre <settembr@UMDNJ.EDU>
To:rkline@emscience.com
Reply-To:
Content-Type:TEXT/PLAIN; charset=US-ASCII

On Fri, 7 Apr 2000 rkline@emscience.com wrote:

> Sorry, I was thinking pH strips when the conversation was about pH paper.
> 
> I would not recommend using pH paper, but I would pH strips.  There is a major
> performance difference.
> 
> pH paper is filter paper impregnated with indicator or indicator mixture vs pH
> strips incorprate special indicator dyes covalently bound to the cellulose of
> reagent paper.
> 
> Results on pH strips are highly reproducible.
> pH strips have clearly defined colour differences between pH ranges and are
> easier to read.
> pH strips are highly accurate in weak buffers, subsequent to waiting 5-10
> minutes for an indicator on a meter to reach equilibrium.
> Strips do not bleed and can be left indefinitely in test medium.
> Strips can be used in weakly colored and turbid solutions because they can be
> rinsed off.
> 
> If I knew about these while I was working in a lab, I would have been using
> them.  They would have saved a lot of valuable time.  We sell strips into the
> biopharm and biotech industries where measurements are as critical in comparison
> as clinical measurements.  One of the applications they use them for are
> enzymatic studies besides measuring buffer solutions and other things.
> 
> Sometimes a change of mind is hard to come by.  It's all a matter of what you
> are comfortable with and in the clinical arena, I am only to familiar with that
> feeling.  But I do think as technology progresses, a change of mind might
> expediate things a bit  especially where turn-around-time is critical and
> staffing is short.
> 
> If anyone is interested in trying strips, send me your address.  I can have
> samples sent out.   I would be interested to hear about your results and
> feelings.
> 
> Regards,
> Rande Kline, HT (ASCP)
> Technical Services
> EM Science/BDH.
> 
> 
> 
> 
> 
> 
> 
> Gayle Callis <uvsgc@msu.oscs.montana.edu> on 04/03/2000 02:55:51 PM
> 
> To:   histonet@pathology.swmed.edu
> cc:    (bcc: Rande Kline/EMI/Merck)
> Subject:  RE:pH paper vs. meter
> 
> 
> 
> Tamara is correct, and at the risk of offending someone, I consider this
> neither good advice nor good laboratory technic.
> 
> Gayle Callis
> 
> 
> >Date: Wed, 05 Apr 2000 17:27:15 -0400 (EDT)
> >From: Tamara Howard <howard@cshl.org>
> >Subject: RE:pH paper vs. meter
> >To: raws43@hotmail.com, Histology listserver
> >    <histonet@pathology.swmed.edu>
> >
> >>Lori Steele from Biogenex just gave a lecture at our State meeting.  She
> >>said that a pH meter is not necessary to check the buffer solution for
> >>immunohistochemical staining - just use a pH tape with 1.0 intervals.
> >>However, it still needs to be done each day you do IHC staining.  I know
> >>in our busy lab, it sure is quicker than having to use the meter.
> >
> >>Becky Scholes
> >>Iowa Pathology Associates
> >>Des Moines, Iowa
> >
> >Sorry, but this is not a good idea. Try for yourself - round up some pH
> >papers - different ranges and vendors - and try all on one buffer. My bet
> >would be that you'll get readings all over the place. Quicker may be nice,
> >but reproducibility is really worth the extra time - and it takes less
> >than 5 mintues to properly calibrate a meter and check your buffer's pH.
> >
> >Tamara Howard
> >CSHL
> >
> >
> >
> >
> 
> 
> 
> 
> 
> 

I would be interested in trying your pH "strips"

Dana Settembre
Immunohistochemistry Lab
Pathology Department
University Hospital
150 Bergen Street, E153
Newark,  New Jersey  07103-2406
USA




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