[jmjengland]

Good evening all,

I would like to know if someone of you know how to measure pH of slurry. A suspension is 2-trifluoromethylbenzoylamide and potassium carbonate in water heated to 70 degrees and after that the pH of the solution is tested but it is problematic because of solidifying of the solution (it is probably changing consistency with temperature).

Thank you.

[Borek]

pH is well defined only for water solutions, are you sure your slurry still qualifies?

[jmjengland]

I know pH is defined for solutions, I am sure that this slurry still qualifies for pH, it is just to find the method how to measure pH of slurry, it is weird but the pH needs to be 11.0-11.5 to proceed with reaction.

[marquis]

Yes, pH of slurries is done.  If you are just using the pH for process control,
you can do a dilution (say 10%) and measure the pH of the dilution.

A word of caution.  Slurries tend to clog up pH electrodes, which normally
are somewhat porous.  So at the very least, you need to clean the electrode often.
Also, you're getting to the pH where alkaline metal error can lead to
problems on some types of pH electrodes.

[WW]

Slurries are often done to measure sediment/pore water PH, and I think can even be used to measure soil pH if distilled water is added.  the key is stirring, make sure the suspension is homogenized.  if there are too many solids, dilute with distilled water and do a back calculation to determine the pH of the original solution.