Selective Fabrication of an Electrochemical Sensor for Pb ²⁺ Based on Poly(pyrrole‐co‐ <i>o–</i> toluidine)/CoFe ₂ O ₄ Nanocomposites

Abstract We report the synthesis of a novel nanocomposites based Poly(pyrrole‐co‐o‐toluidine) copolymer and cobalt ferrite (CoFe 2 O 4 ) as an electrochemical sensor for selective Pb 2+ detection. The general abbreviation of these new materials are given as P(Py‐co‐OT)/CF nanocomposites (P(Py‐co‐OT)/CF NCs). The synthesis was performed via in situ‐chemical oxidative polymerization method at different CoFe 2 O 4 weight ratio (5%, 10%, 30%, 50% and 70%), whereas CoFe 2 O 4 nanoparticle (NPs) was synthesized by an egg white method prior the nanocomposite formation. The structural, morphological, thermal, magnetic, electrical and electrochemical properties of pure P(Py‐co‐OT), CoFe 2 O 4 and P(Py‐co‐OT)/CF NCs were characterized by XRD, FTIR, TGA‐DTG, SEM‐EDX, TEM, VSM and electrical conductivity. The results of XRD and FTIR confirmed the formation of P(Py‐co‐OT)/CF NCs with the component CoFe 2 O 4 showing spinel structure. The analysis of TGA‐DTG presented that CoFe 2 O 4 NPs improved the thermal stability of NCs indicated the presence of some interactions between the interface of P(Py‐co‐OT) and CoFe 2 O 4 NPs, which affects the chemical and physical properties of the NCs. The ac conductivity was also examined as a function of temperature. The measures showed a decrease in the conductivity of NCs when increasing the insulating CoFe 2 O 4 NPs contents. A cost‐effective and reliable electrochemical sensor selective to Pb 2+ ion was fabricated using P(Py‐co‐OT)/CF NCs on glassy carbon (GCE). It was found that the P(Py‐co‐OT)/CF 10 NCs exhibit excellent detection of Pb 2+ ion. The proposed Pb 2+ ion sensor was performed linearly over the large concentration range of 0.1 nM ∼ 0.01 mM labelled as linear dynamic range (LDR). The sensitivity as well as detection limit were estimated to be 22.39 μAμM −1 cm −2 and 42.39 ±2.12 pM, respectively. The desired ionic sensor‐based on P(Py‐co‐OT)/CF 10 NCs/binder/GCE was found as efficient to detect Pb 2+ ion in environmental and biological samples significantly. The analytical sensor performances such as reproducibility, sensitivity, stability, validation, and response time were reliable and significant.