A novel electrochemical sensing platform based on Pt/PPy/Eosin-Y for the determination of cadmium

Abstract

In this research work, a novel sensing platform has been designed for the determination of cadmium (Cd²⁺) based on the modification of a bare platinum (Pt) electrode with pyrrole (Py) and Eosin-Y (yellowish) using electro-polymerization and electro-deposition procedures. When the bare Pt electrode was modified as Pt/PPy/Eosin-Y, two distinct and highly sharp anodic and cathodic peaks appeared at the potentials of −0.55 V, and −0.9 V versus a Ag/AgCl reference electrode, respectively. Furthermore, this new modified electrode exhibited excellent electrochemical responses toward Cd²⁺ with linear behavior over the concentration ranges of 10–100 nM and 150–400 nM using the differential pulse voltammetry (DPV) technique. In addition, the scanning electron microscopy (SEM) images showed the formation of nanocomposite structures on the surface of the bare Pt electrode, indicating the enhanced surface area and the successful performance of the electro-polymerization and electro-deposition procedures. The modified electrode also displayed excellent electro-catalytic properties (α = 0.88, K_s = 0.028 S⁻¹, and Γ = 4.3 × 10⁻⁹ mol cm⁻²) for the oxidation of Cd²⁺ at the optimized pH of 6 and the working potential of −0.55 V (vs. Ag/AgCl). Owing to the good selectivity and high sensitivity of the proposed sensor, it was successfully used for the determination of the Cd²⁺ content in real samples with satisfactory results and free from side interferences.