How to Measure Resistivity of Liquid Solutions

It's usually measured as conductivity (the reciprocal of resitance) in Milli or micro Siemens. Google conductivity of liquids.
It's pretty temperature sensitive and can get confused with/by other factors such as ph. It's usually measured by putting an ac voltage across two probe pins (say 15v peak to peak at anything from 50hz to a few khz) in the liquid. There are inductive methods too.
It's a pain in the a$$
Del

This link may have the information you require.

http://www.coleparmer.ca/techinfo/techinfo.asp?htmlfile=Conductivity_faq.htm#anchor8

We use Extech brand meters, to monitor the conductivity of the distilled water, coollng our power electronics.

Good Luck

Thanks for advice and links. I think I can get what I need from there. I'm more of a mechanical guy so this electrical stuff is a little out of my league. Thanks again.

Commercial conductivity/resistivity meters for ionic solutions are widely available. Do note, however, that Kohlrausch Water, a theoretically pure H₂O-only material, has a resistivity of 18.8MΩcm @20degC, so it can't go any higher than that.

The resistivity of non-ionic liquids is a non-starter as a concept. After all, they are good electrical insulators.

Thanks. Measuring the resistivity is to verify that we haven't ionized the solution as to make it conductive enough that the electrical current at the end of the process can backfeed/leak through the system and damage any more of our equipment. And with 15-20 Kvolts it doesn't take much for it fry the equipment. I have one of the meters in the link posted above on order, hopefully it does the trick.