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Problems with pH readings all over the place


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#1 jack44

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Posted 14 August 2009 - 07:38 AM

Made a NaCl solution at .29osm/L and tried to pH it like I've done for years and could not get a steady reading at 7.4, but rather at either 5 or 9 pH!!!
Can the plastic bag that the NaCl came out of have leched plasticises into the solution, and can plasticises bind to the junction of the probe?

Edited by jack44, 14 August 2009 - 07:41 AM.


#2 Gerard

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Posted 14 August 2009 - 07:51 AM

Two level calibration is working ok?
Ockham's razor
Pluralitas non est ponenda sine necessitate
-- "You must assume no plural without necessity".

#3 phage434

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Posted 14 August 2009 - 09:12 AM

If you make the solution with pure chemicals and high quality water, there is essentially nothing to buffer the pH. It is not surprising that breathing on it the right way will change the pH dramatically.

#4 hanming86

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Posted 14 August 2009 - 07:08 PM

try another pH probe and see.
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