1989 Volume 37 Issue 5 Pages 1307-1310
The magnitude of the photoinduced membrane potential actoss poly(vinyl chloride)/spirobenzopyran membranes doped with nonactin or valinomycin depended considerably upon the kind and the concentration of alkali-metal and NH+4 cations in the aqueous solution adjacent to the ultraviolet (UV)-irradiated surface of the membrane. The photoresponse was suppressed with increasing concentration of the cations. The ion-selectivity in the potentiometric photoresponse of the nonactin-entrapped membrane was in the order of NH+4>K+>Rb+>Cs+>Na+>Li+, whereas the order of selectivity of Rb+>K+>Cs+>NH+4>Na+>Li+ was ovserved for the valinomycin-doped membrane. The results can be explained in terms of the binding abilities of nonactin and valinomycin for alkali-metal and NH+4 cations.
