ROLE OF MEMBRANE MEDIA IN POTENTIOMETRIC SELECTIVITY OF ANION CARRIER-BASED ION-SELECTIVE ELECTRODES

Effect of membrane media on potentiometric selectivity of two metallop orphyrin anion carriers, manganese(III) and molybdenum(V) complexes of tetraphenylporphyrin, is studied by using liquid membrane cell assemb lies. Nitrobenzene, 1,2-dichloroethane, and chloroform are used as liq uid membrane media. Anion selectivities of the two metalloporphyrins i n nitrobenzene and 1,2-dichloroethane liquid membranes are somewhat di fferent from those of corresponding classical anion exchanger-based li quid membranes, but both solvents cannot induce their anti-Hofmeister behavior. On the other hand, both metalloporphryins show clear anti-Ho fmeister anion selectivity sequences in the less polar chloroform memb ranes, indicating important roles of membrane media in selective recog nition of some anions by the metalloporphyrin anion carriers.