A highly sensitive electrochemical detection of multiple heavy metal ions in water using PAni–RYFG/GCE modified electrode: Experimental and DFT studies

Abstract

Here, we report the individual and simultaneous detection of Hg²⁺ and Pb²⁺ ions sensor constructed by a novel polyaniline-yellow 42 dye (PAni-RYFG) composite with the combination of reactive yellow 42 dye (RYFG) moiety and dedoped polyaniline (DD PAni) using chemical oxidative polymerization method. The developed sensor’s morphology and chemical composition were analyzed using various spectroscopic techniques. Further, to serve as an electrochemical interface for sensing Hg²⁺ and Pb²⁺ ions, the PAni-RYFG composite was drop cast on the surface of the glassy carbon electrode (GCE). The electrochemical behavior of the electrode modifiers was studied using the CV and EIS studies. The electrode modifiers’ sensing ability and electrochemical catalytic activity were analyzed using the differential pulse voltammetry (DPV) technique in an acetate buffer solution with varied pH levels, individually and concurrently. PAni-RYFG/GCE electrode was shown to have a strong electrochemical response and outstanding electrocatalytic activity for the distinctive identification of Hg²⁺ and Pb²⁺ ions from other heavy metal ions in concentrations ranging from 1 to 21 μM, the detection limits (S/N = 3) were 2 and 6.2 nM, respectively. The selectivity of PAni-RYFG/GCE was examined based on the influence of interfering agents on the signals of the targeted metal ions. Likewise, the applicability of the DPV was checked in real water samples. Interestingly, the recovery percentages above 100 % for all water samples evidenced the authenticity of PAni-RYFG/GCE for Hg²⁺ and Pb²⁺ ions determination in real water samples. Density Functional Theory (DFT) determined the proposed sensors’ adsorption process.