Potentiometric Ion-Selective Electrode Based on a New Single Crystal Cadmium(II) Schiff Base Complex for Detection of Fluoride Ion: Central Composite Design Optimization

Here, we present the use of single crystal structure of cadmium iodide complex (CdLI ₂ ) as fixed-charge carriers for the development of fluoride (F ^- ) anion selective electrode. The (E)-N1-(2-nitrobenzylidene)-N2-(2-((E)-(2-nitrobenzylidene) amino) ethyl) ethane-1,2-diamine (L) Schiff base ligand was prepared and its complex via CdI2 (CdLI2) as efficient indicator was impregnated into carbon paste electrode. Physicochemical properties of CdLI ₂ were identified by FT-IR, FE-SEM and XRD analysis. The effect of CdLI ₂ concentration on fluoride selective electrode resistance is measured using electrochemical impedance spectroscopy, and a significant increase in electrode resistance is observed with increasing CdLI ₂ as well as cyclic voltametry was used for estimation of prepared electrode surface area and the interface capacitance of prepared ion selective electrode. The operational parameters in measuring the Nernstian slope of 58.966 mV/decade were investigated and optimized using central composite design. The proposed ISE showed low detection limit, fast response time, and most significantly, very good selectivity with respect to the group of some anions (IO ₄ ^- , SCN ^- , SO4 ^2- , CN ^- , ClO ₃ ^- , Br ^- , Cl ^- and I ^- ). The proposed ISE was successfully regenerated by soaking in distillated water and polished on greaseproof paper, and its response was reversible with the relative standard deviation (R.S.D.) at 2.0%.