Ion–ionophore interactions in polymeric membranes studied by thin layer voltammetry

In ion sensing applications, selective ion-receptor complexation is the molecular basis for endowing material with selectivity. this work, thin polymeric membrane-based transfer voltammetry used to investigate complexation, using a range of electrically neutral ionophores and surfactants as examples. Previous studies lacked convincing approach eliminate influence from transducing layer, resulting in deviations observed binding constants compared potentiometric methods. A recently developed method allows subtracting potential changes thereby overcoming challenge. Using approach, are assessed. Valinomycin detection potassium gave logarithmic complex formation constant membrane 9.69 ± 0.25 1:1 stoichiometry. Lithium ionophore VI lithium stability 5.97 0.06 1:2 complexes; while sodium X (7.57 0.03, 1:1) calcium IV (21.57 0.25, 1:3) were also characterized, addition their complexes interfering ions. The three explored membranes containing valinomycin, Brij-35 (4.88 0.08, 1:1), Triton X-100 (5.63 0.10, F-127 (4.63 0.49, 1:1). Limitations discussed, which includes need electrochemical reversibility sufficiently high lipophilicity adequately retain components