Although most Karl Fischer Titrators have a calibration function most people don't even use them.  Instead it is much simpler to run a water standard through the Karl Fischer Titrator like a normal test.  Using the water standard you are able to determine if the Karl Fischer Titrator accurately calculated the result.

We use Hydranal water standards.  There are two kinds typically used.  1) 0.1 normal and 2) 1.0 normal. 

The 0.1 normal administered at about 1mL should result in 100PPM (Parts Per Million) of moisture when measured.  The acceptable result for this standard from the Karl Fischer titrator is +- 10%.  So your Karl Fischer Titrator should produce a reading between 90PPM and 110PPM to be in the acceptable range.  If it is, you know your Karl Fischer Titrator is performing correctly.

For the 1.0 normal everything is the same except for the standard should result in 1,000PPM and your acceptable range is smaller at +-3%.  So your Karl Fischer Titrator should produce a reading between 970PPM and 1,030PPM.

I found this great video on Sigma Aldrich's site that shows this process (it also goes into some additional detail for conducting a water standard test).  To see it go to:

http://www.sigmaaldrich.com/Area_of_Interest/Analytical__Chromatography/Video/HYDRANAL/water_standard_use.html


Hope this helps.

H.