I had this same question. Would like to use for just measuring potentials, like ORP, pH, ISE, etc. From my research, if you take the counter electrode out of the circuit, you can make this measurement. I haven't got one to try this on yet. Suggest you research "open circuit potential" on web. Seems to be similar question on other potentiostats.
Posts made by Robert
RE: Can Rodeostat be used to measure the potential with zero current? (i.e. can 2 electrodes be used instead of 3?)