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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: huh on January 10, 2014, 08:25:30 PM

Title: thoughts? {ph of viscious sample}
Post by: huh on January 10, 2014, 08:25:30 PM
Not sure if this is in the correct subforum, but I'm seeking the opinion of other chemists on this one.

I'm a chemist for a company who basically manufactures VERY viscous materials. We're currently having a problem with a few products not giving us accurate ph readings, and I am assuming it is due to the electrode not necessarily being made for viscous materials (we manufacture other products as well, which is why the lab is currently using an electrode made for all kinds of samples).

That said, our standard operation/test method clearly states we must shake the electrode for the entire reading (makes sense if taking the ph of anything other than high-viscosity materials), however, as you may know, the viscous material makes this method difficult... by creating a "hole" around the membrane, therefore... turning inaccurate results.

Other than A) buying a ph meter made for high-viscosities, or B) changing the test method, are there any other obvious options I might be missing?

Thanks guys.

Title: Re: thoughts?
Post by: Arkcon on January 10, 2014, 09:20:13 PM
What you need when you take a pH is stirring, although shaking is sometimes easier.  At any rate, if you can stir slowly enough to move the sample without making a cavity, you might get better readings.