RE:pH paper vs. meter
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From: | "J. A. Kiernan" <jkiernan@julian.uwo.ca> |
To: | Histonet <Histonet@pathology.swmed.edu>, rkline@emscience.com |
Reply-To: | |
Content-Type: | TEXT/PLAIN; charset=US-ASCII |
On Fri, 7 Apr 2000 rkline@emscience.com wrote:
> pH strips are highly accurate in weak buffers, subsequent to waiting 5-10
> minutes for an indicator on a meter to reach equilibrium.
If a pH meter takes 5-10 minutes to give a steady reading, whatever
it's immersed in, it needs a new electrode. The only exception
would be an older meter that uses an electrometer tube (=valve) in
its amplifier (rather than all solid-state electronics). An older
meter may take an hour or so to "warm up" and it should then be
left switched on all the time. (Current consumption is almost
zero.) Modern meters, including those with "digital" displays,
do not need a warm-up time. These statements are certainly true
of the three electrometer-type and four digital-type pH meters
that I've had in my lab over the years. It's the electrodes that
get broken or wear out - sometimes because of neglect.
> ... We sell strips ...
> If anyone is interested in trying strips, send me your address. I can have
> samples sent out.
Please! (Address below)
John Kiernan. London, Canada.
John A. Kiernan,
Department of Anatomy & Cell Biology,
The University of Western Ontario,
LONDON, Canada N6A 5C1
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