non-sensitive FET: In order to produce reference
electrodes without liquid junction, it is necessary that such
electrodes should have a membranerelectrolyte interface
where electrolyte cannot cross by diffusion, then a stable
potential drop is established and this potential drop is
independent of the electrolyte composition. At first sight, it
appears to be impossible to satisfy all these criteria; nevertheless,
one of the tricks which has been proposed is to use
a plasticized PVC membrane. Calculations of the interfacial
potential difference at waterrhydrophobic phase interfaces
have been performed 16 and used in order to design w x
reference electrodes 17 . In our work, the composition of w x
the non-sensitive FET membrane was PVC and DNP in a
ratio of 7:3 wŽ . rw diluted in THF. Such a composition
was also used for the non sensitive FET membrane in pH
measurements and satisfactory results were obtained in
differential measurements