Anyone out there with experience using the KF coloumeter with oven and nitrogen for H2O analysis in refrig oil?
I am courius to if the different refrigerants diluted in the samples will surpress the nitrogen to carry out the H2O of the sample vial during boiling session in the oven. Most of our samples are diluted with NH3, R134a, R407 and CO2.

We use this setup for testing refrigeration oils containing small amounts of refrigerant, as well as refrigerants containing larger amounts of oil. We don't add refrigerant directly to the KF cell if it has more than 0.1 percent oil to keep the KF cell clean as long as possible.

The refrigerant makes no difference to the moisture results.

I have no personal experience with CO2, since we are in the USA and almost no one uses it commercially. The others I have plenty of experience with, and have not had any issues with accurate and repeatable moisture results.

Thanks for replying, and for sharing your experiences as always. Its hard to get solid answers, even the insturment supplier had nothing to comment (had no idea).