Silver-ligand complex as an additive in polymeric membranes of screen-printed fluoride-selective electrodes

[Display omitted] •Dithizone-silver complex was used to stabilize electrode potential for the first time.•Dithizone-silver complex can act as lipophilic cationic additives within the membrane.•Screen-printed electrodes selective towards fluoride were developed. Fluoride-selective electrodes with membranes containing zirconium porphyrin and dithizone-silver complex were developed. Silver disc electrodes and devices fabricated by screen-printing with silver ink were used as transducers. Dithizone-silver complex ensures potential stability of prepared electrodes, forming a redox couple with silver metal transducers. Moreover, it serves as lipophilic cationic site in the membrane, inducing zirconium porphyrin to act as a neutral ionophore. Electrodes with these membranes showed the following selectivity sequence: ClO4− > F− > NO3– > Cl−. Linear response towards fluoride was observed from 10−4 M to 10–1 M. Charged carrier mechanism is also possible, requiring polar plasticizer and addition of anionic lipophilic sites to the membrane. While membranes with ionophore working as charged carrier show better discrimination of lipophilic anions (selectivity sequence: F− > ClO4− > NO3– > Cl−), dynamic range of fluoride response is narrower in this case (10−4 M to 10−2 M), as compared to membranes with ionophore working as neutral carrier. Screen-printed electrodes with membranes containing dithizone-silver complex were integrated with reference electrodes with membranes containing ionic liquid, prepared on the same transducers. These devices were successfully employed for determination of fluoride ion in pharmaceutical samples.