Voltammetric Sensors based on Benzimidazole Derivatives by Changing Substituents on the Pyrimidine Ring

Abstract

A new series of voltammetric sensors based on benzimidazole derivatives were used for the quantitative detection of metal ions. Benzimidazole derivatives namely, GK-4, GK-14 and GK-15 were studied. The receptors GK-15 and GK-14 were highly selective for the detection of Fe2+ and Ag+ ions, respectively using ACN:DMSO (8:2) mixture as a solvent medium. The closely packed three nitrogen atoms of Schiff base moiety and pyrimidine ring in the receptor motif were responsible for redox behaviour of the compounds. Voltammertric studies were carried out in the applied potential range -2.1 V to -0.5 V using cyclic voltammetric techniques. GK-15 and GK-4 show both anodic and cathodic peaks at -1.58 V and -1.64 V, respectively, while GK-14 shows cathodic peak at -1.8 V and anodic peak at -1.7 V. A linear calibration curve between peak current and concentration of the metal ions was observed in concentration range of 5.0×10-7 to 3.0×10-6 M with a detection limit of 1.98×10-9 M for GK-15. Based on quenching of the cathodic peak potential of GK- 15 in the presence of different concentrations of metal ions, the proposed sensor shows 1:1 stoichiometry with Fe2+ ions in ACN:DMSO medium. No significant interference was observed from other metal ions except with Ag+ . GK-15 was successfully used for the detection of Fe2+ ions in real samples and results were confirmed with AAS.