An ion-selective membrane based on a polyimide polymeric matrix plasti
cized with diethylene glycol dibenzoate and containing calcium synthet
ic ionophores was used to obtain a potentiometric Ca2+ sensor. It give
s a linear response over the pCa range 1-5 with a slope of 27.4 mV (pC
a)(-1). The sensor can be used for the pH range 3-8.5. The calcium-sel
ective membranes were characterized in terms of their surface morpholo
gy and the structural parameter, the glass transition temperature. The
ac impedance and FTIR analysis of the polyimide-based polymeric membr
ane were also studied.