Uranyl-selective PVC membrane electrodes based on some recently synthesized benzo-substituted macrocyclic diamides

Four different recently synthesized macrocyclic diamides were studied to characterize their abilities as uranyl ion carriers in PVC membrane electrodes. The electrodes based on macrocycle 1,18-diaza-3,4;15,16-dibenzo-5,8,11,14,21,24-hexaoxacyclohexaeicosane-2,17-dione resulted in a Nernstian response for UO22+ ion over wide concentration ranges. The linear concentration range for the polymeric membrane electrode (PME) is 3.0×10−6–8.2×10−3 M with a detection limit of 2.2×10−6 and that for the coated graphite electrode (CGE) is 5.0×10−7–1.5×10−3 M with a detection limit of 3.5×10−7 M. The electrodes manifest advantages of low resistance, very fast response and, most importantly, good selectivities relative to a wide variety of other cations.