DESIGN OF A CALCIUM-SELECTIVE OPTODE MEMBRANE BASED ON NEUTRAL IONOPHORES

A large variety of new optical ion-sensor constructions (op-todes) can now be realized by using a poly (vinyl chloride) (PVC) membrane that Incorporates a cation-selective neutral ionophore, a specially tailored H+-selectlve neutral chro-molonophore, and lipophilic anionic sites In the same plasticized PVC membrane. Such membranes generally combine the advantages of a highly selective and reversible recognition of given Ionic substrates and of a straightforward optical transduction of the recognition process. The present membrane exhibits the theoretically expected absorbance response to Ca2+ activities In different pH-buffered samples. Dynamic range, reproducibility, response time, long-time stability, and selectivity of the new optode membrane are discussed. © 1990, American Chemical Society. All rights reserved.