We are using Ag\AgCl electrodes and KCl salt bridges for liquid junction potential measuring in NaCl solution. The concentration ratio is 10:1. Theoretical value is -11,6 mV. But measured values in the range -4 .. -9 mV. In some cases there is no stabilization for potential during measurent.

Who has experince for measurement of liquid junction potential for NaCl solutions? Can somebody advise experimental protocol? How long we need wait for the stabiluzation during measurement? What is the reason for unstable behaviour?