Volumetric Karl Fisher

[d***@gmail.com]

I'm in the process of putting together a Volumetric Karl Fisher
apparatus and have a few questions. There are three peices of the
apparatus that I need to purchase.

-double platinum electrode
-ammeter/voltmeter ( 0 to 100 microamps, 10-20 mV)
-drying zeolite sieve and tube to connect to the KF reagent to the
burette.

My first question is how can I be assured that a purchased platinum
electrode will connect to the ammeter. My preference would be
striped wires connected to +/- terminal with screw provided on the
ammeter/voltmeter. For the ammeter my preference for visualization of
the stop/end point would be an analog needle. Also, is a battery
operated ammeter better for this set-up due to resistance. Lastly,
price is a major concern as always.

Thanks and Regards

[Bob M]

I built my own several years ago I have a commerially made metrohm
electrode Making your own is easy enough. I have an analog meter
indicator on the tail end of a few solid state electronics. There is a
little more than you think as very small electrodes dont use much
current and you require a nice stable voltage controlled voltage
across the electrodes for good results.
I use Hydranal composite 10 titrate it does not pong like the old
pyridine reagent also it reacts quicker. For drier tube I use silica
gel with a very low flow air supply from an aquarium pump with a flow
restrictor to the the reaction vessel and another drier tube to the
top of the burette
Bob M
www.molab.co.nz