The fabrication of TiO₂/AgCNF/Nafion/GC electrodes for simultaneous electrochemical detection of Cd(II), Pb(II), Cu(II), and Hg(II) by optimizing the porosity of electrospun TiO₂ nanofibers

Through the manipulation of electrospinning solution properties, we tuned the morphology and porosity of electrospun titanium dioxide (TiO₂) nanofibers. Using a modified glassy carbon electrode (GCE) with TiO₂ nanofibers and Ag-coated carbon nanofibers (AgCNFs) with nafion as a binder, heavy metal ions (HMIs) have been detected with nanomolar detection limits using square wave anodic stripping voltammetry (SWASV). It has been determined how the Cd²⁺ current signal responds to changes in deposition potential, deposition time, buffer solution pH, and drop-cast volume. The estimated sensitivity of Cd²⁺ is 49.98 µA µM⁻¹ and the limit of detection (LOD) is found to be 12.75 nM by the three-sigma (3σ) method. The TiO₂/AgCNF/nafion/GCE electrode can simultaneously detect Cd²⁺, Pb²⁺, Cu²⁺, and Hg²⁺ ions without mutual interference. The sensitivities toward Cd²⁺, Pb²⁺, Cu²⁺, and Hg²⁺ are 39.59, 42.75, 15.67, and 10.52 µA µM⁻¹, respectively. The LOD toward Cd²⁺, Pb²⁺, Cu²⁺, and Hg²⁺ are 40.14, 31.69, 93.31, and 208.26 nM, respectively. These quantities fall far short of the WHO’s recommended guideline values. This combination of very porous TiO₂ nanofiber with AgCNF leads to an innovative sensor platform that has very low LOD compared to the previous sensors that have been reported.