Electrochimica Acta, Vol.166, 17-25, 2015
Highly Selective Amide-tethered 4-aminoquinoline-beta-lactam Based Electrochemical Sensors for Zn (II) ion Recognition
Highly selective and unprecedented 4-aminoquinoline-beta-lactam (AQL) based electrochemical (voltammetric & potentiometric) sensors for the selective recognition of Zn (II) ions have been developed. Preliminary, the complexation behavior of AQL towards various metal ions was investigated by employing the UV-visible and fluorescence techniques. The voltammetry of AQL exhibits two anodic peaks at 0.85V and 1.25V which get shifted toward more positive potential (anodic shift) on addition of Zn (II) ions in the potential range of 0.40 V to 1.60 V vs Ag/Ag+ due to formation of AQL-Zn (II) complex. Voltammetric sensor exhibited linear response in the wide concentration range of 5.0 x 10 (5) to 6.0 x 10 M-4 with detection limit of 2.5 x 10 (6) M. Potentiometrically, the polyvinyl chloride based solid contact coated graphite electrode (CGE-1) showed the Nernstian slope of 28.9 mVdecade (1) in concentration range of 1.0 x 10 (1) to 1.0 x 10 M-7 with detection limit of 8.26 x 10 (8) M. The high binding constant and negative value of free energy calculated by using the Benesi-Hildebrand equation confirmed the formation of AQL-Zn (II) complex and further validated via H-1-NMR and mass spectrometry. The developed electrochemical sensors exhibited high selectivity and reproducibility toward Zn (II) ions. The analytical utilities of proposed sensors were confirmed by the quantification of Zn (II) content in various sample matrices. (C) 2015 Elsevier Ltd. All rights reserved.