Primary amine drug sensitive electrodes based on macrocyclic polyethers with 2,2?-dinaphthyl subunits

Carrier-Based Ion-Selective Electrodes and Bulk Optodes. 2. Ionophores for Potentiometric and Optical Sensors

“…The fairly high discrimination of several inorganic cations and a number of organic cations, such as adrenaline ( A-13 ), ephedrine ( A-3 ), and some alkaloids, was obviously not only due to specific interactions between the primary ammonium group and the ionophore but also due to the highly hydrophobic character of the 1-phenyl-2-propyl substituent on the primary analyte (see also section IV.6 on ionic surfactants, commenting the use of dibenzo-18-crown-6 for the detection of primary alkylammonium ions). For sensing the very similar analytes benzylamine and mexiletine ( A-14 ), macrocyclic polyether derivatives of o -phenanthroline and 2,2‘-dinaphthol with various ring sizes were incorporated into PVC membranes. − Due to specific interactions between the primary ammonium ions and the ionophore, the selectivity sequence for an electrode with a bridged o -phenanthroline ( AM-8 ; RNH 3 + > R 4 N + > R 3 NH + > R 2 NH 2 + ; R = ethyl) clearly differs from that for typical ion-exchanger ISEs (R 4 N + > R 3 NH + > R 2 NH 2 + > RNH 3 + ), which is determined by the lipophilicities of the measured ions. A similar but smaller effect was also observed for ISEs with a calix[6]arene ( Cs + -4 ) or a p -1-adamantylcalix[8]arene , ( AM-9 ) ionophore.…”