Trace electrochemical detection of Ni2+ ions with bidentate N,N′-(ethane-1,2-diyl)bis(3,4-dimethoxybenzenesulfonamide) [EDBDMBS] as a chelating agent

Abstract

The heavy metals are naturally occurring elements and becoming the main source of pollution in our eco-environment due to their commercial applications. So, for the probe of heavy metal cations, bidentate chelating agents N,N′-(ethane-1,2-diyl)bis(4-methoxybenzene sulfonamide) [EDBMBS] and N,N′-(ethane-1,2-diyl)bis(3,4-dimethoxybenzenesulfonamide) [EDBDMBS] were synthesized in this study. These chelating agents were characterized by UV/Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H-NMR &13C-NMR), in addition to single-crystal X-ray diffraction and X-ray photoelectron spectroscopy (XPS) analysis. After the characterization, I-V technique was executed using electrometer to check the affinity of our synthesized chelating agents against the wide range of heavy metal cations (Ag+, Al3+, Au3+, Ba2+, Ce4+, Co2+, Ni2+, Pb2+, Sn2+ & Y3+). It was found that it has selective affinity with Nickel (Ni2+) cations. Ni2+ is one of the most toxic heavy metal presents in the environmental contaminants. EDBMBS and EDBDMBS onto flat-glassy carbon electrode were fabricated with conducting coating agents to fabricate a sensitive and selective Ni2+ ions sensor in short response time in phosphate buffer phase. The comparative study of EDBMBS/Nafion/GCE and EDBDMBS/Nafion/GCE was performed and found that fabricated EDBDMBS/Nafion/GCE cationic-sensor exhibited higher sensitivity, large-dynamic concentration ranges, long-term stability, and improved electrochemical performances towards nickel ions. The calibration plot is linear (r2=0.9929) over the large Ni2+ concentration ranges (1.0nM to 1.0mM). The sensitivity and detection limit is ∼2.3417µA.µM.cm−2 and ∼0.78nM (signal-to-noise ratio, at a SNR of 3) respectively. This novel effort initiated a well-organize way of efficient cationic sensor development with nafion conducting binder deposited on GCE for toxic pollutants in environmental and health-care fields in large scales. Therefore, the proposed EDBDMBS/Nafion/GCE offers a cost-effective compound that can be considered as a viable alternative for effectively detecting and removing toxic Ni2+ from water samples.