Can the Alkalinity application on the AT1000 be used in dirtier sample types like waste water?

Document ID

Document ID TE10101

Version

Version 1.0

Status

Status Published

Published Date

Published Date 07/12/2018
Question
Can the Alkalinity application on the AT1000 be used in dirtier sample types like waste water?
Summary
Advice on using the Alkalinity AT1000 application in dirtier sample types.
Answer
The Application packs for alkalinity are intended for use in a cleaner sample types like drinking water. This is because the pH electrode included with the application packs is the PHC805. The PHC805 is the best option for titration in a cleaner application as it has the larger surface area glass bulb and does not use the saturated electrolyte which makes it easier to maintain than alternatives. It also has a porous pin junction which provides a slower electrolyte flow rate which means that it does not need to be refilled as often as other alternative and saves consumable cost. The trade off is that the porous pin junctions can get clogged by solids in dirtier samples.

This probe will work in dirtier samples, as long as it passes calibration and users can obtain good recoveries on standards. However the probe's functional life will be shorter in dirtier applications than in clean water applications.

If after cleaning (See also: How should pH and conductivity electrodes be cleaned?) and replacing the filling solution (See also: What is the procedure for replacing the filling solution in a refillable pH probe?) the probe wont pass calibration or bad multiple lots of standards give poor recoveries, this indicates that the probe should be replaced.

When the probe is replaced, it could be replaced with another PHC805, a similar lifespan could be expected out of the replacement probe, but no changes would need to be made to continue to use the sample probe.

Alternatively the probe could replaced with a different probe that is recommended for dirtier samples. The PHC73501 would be the recommended probe for titration in a dirtier sample. This probe would likely have a longer life than the PHC805 in a dirtier application. However there are some trade offs: 
  • It uses a different solution for filling and storage than the PHC805, and will go though filling solution faster due to a faster flow rate meaning that the probe would need to be refilled more often.
  • Also there would be some settings in the application that are specific to the PHC805 that would need to be changed in order for the probe to pass calibrations when using the PHC735.
If a PHC735 is purchased for use with the Alkalinity application on the AT1000, please contact Hach Tech Support at 1800-227-4224 ext. 6122 so that they can walk though making these changes in the application settings.

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