Copper (II) Sensor Based on Pyridinium–Antimony Trichloride Screen Printed Carbon Electrode

This study reports the fabrication and characterization of a screen-printed carbon electrode (SPCE) modified with pyridinium-antimony trichloride (PAT) for copper ion (Cu²⁺) detection in aqueous environments. The SPCE was prepared by printing carbon ink onto a polyethylene terephthalate-mica substrate, while the PAT material was characterized using transmission electron microscope (TEM), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Electrochemical performance was evaluated using cyclic voltammetry, electrochemical impedance spectroscopy, and chronocoulometry, exhibited two distinct linear ranges (0.1–10 μM, R<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.998; 0.1–10 mM, R<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.938). The sensor demonstrated exceptional selectivity against ten interfering metal ions, exhibiting high reproducibility (relative standard deviation, RSD, 2.08%) and repeatability (RSD 3.22%). These metrics confirm the sensor's reliability and consistency in Cu<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> detection.