Fabrication of Sb³⁺sensor based on 1,1′-(-(naphthalene-2,3-diylbis(azanylylidene))bis(methanylylidene))bis(naphthalen-2-ol)/nafion/glassy carbon electrode assembly by electrochemical approach

A new Schiff base named 1,1'-(-(naphthalene-2,3-diylbis(azanylylidene))bis (methanylylidene))bis(naphthalen-2-ol) (NDNA) derived from 2,3-naphthalenediamine and 2-hydroxy-1-naphthaldehyde was synthesized by condensation reaction and then characterized by spectroscopic techniques for structure elucidation. In addition to spectroscopic techniques, the molecular structure of NDNA was clearly confirmed by single-crystal X-ray diffraction study. A thin film of NDNA was fabricated onto glassy carbon electrode (GCE) using 5.0% ethanolic nafion solution as a conducting binder in order to develop the cationic electrochemical sensor (NDNA/nafion/GCE) for the sensing of heavy-metal cations in aqueous systems by electrochemical technique. This newly designed sensor exhibited higher sensitivity and selectivity towards antimony (Sb³⁺) in the presence of other interfering heavy metal cations, as well as long-term stability. Fascinating analytical parameters such as limit of detection (LOD = 0.075 nM, SNR of 3), limit of quantification (LOQ = 0.25 nM) and sensitivity (12.658 × 10^-4 μA μM^-1 cm^-2) were calculated from the calibration curve plot, which shows a linear dynamic range (LDR) of Sb³⁺ ion concentration from 0.1-10.0 mM. This work presents a new approach towards the development of sensitive, efficient as well as selective toxic cationic electrochemical sensors in the environmental and healthcare fields. Hence, this newly designed NDNA/nafion/GCE presents cost-effective and efficient outcomes and can be used as a practical substitute for the efficient detection and removal of Sb³⁺ ions from water samples.