Selective sensing ability of ferrocene appended quinoline-triazole derivative toward Fe (III) ions

Selective electrochemical sensors based on newly synthesized ferrocene appended quinoline-triazole (FAQT) derivative for Fe (III) ions have been developed. The cyclic voltammetry (CV) of FAQT exhibited reversible voltammogram corresponding to ferrocene/ferrocenium redox process in the potential range of −0.4 to 0.6 V vs Ag/Ag+. The CV of FAQT undergoes electrochemical perturbation on addition of Fe (III) ions and results in the shift of voltammogram toward more positive potential (anodic shift) which ascribed the formation of FAQT-Fe (III) complex. The binding behavior and 1:1 stoichiometry of FAQT-Fe (III) complex was further confirmed by employing fluorescence and UV-visible techniques. The high binding constant (1.82 × 103 M−1) and negative free energy change (−18.6 kJ mol−1) indicates the stability and feasibility of FAQT-Fe (III) complex. The voltammetric sensor works within the concentration range of 1.0 × 10−4-5.0 × 10−6 M with detection limit of 2.33 × 10−7 M. The potentiometric solid contact electrode exhibits the Nernstian slope of 18.7 mV decade−1 for Fe (III) ions in concentration range of 1.0 × 10−1-1.0 × 10−7 M with the detection limit of 2.94 × 10−8 M. These proposed sensors showed high selectivity toward Fe (III) ions and therefore, used for quantification of Fe (III) ions in different sample matrices.