A carbon black–doped chalcopyrite–based electrochemical sensor for determination of hydrogen peroxide

A simple, rapid, economical, and non-enzymatic electrochemical sensor for sensitive determination of hydrogen peroxide (H₂O₂) was developed based on a physical combination of carbon black (CB) and pure chalcopyrite modified glassy carbon electrode (GCE). Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) were used to evaluated the morphology of the modified electrode. The proposed sensor (CuFeS₂-CB/GCE) was investigated electrochemically using cyclic voltammetry (CV), amperometric methods (AP), and electrochemical impedance spectroscopy (EIS). The CuFeS₂-CB/GCE sensor exhibited excellent stability and sensitivity with a linear concentration range from 2.5 to 60 mM (R² = 0.9903) using CV and 0.1 to 100 mM (R² = 0.9999) using AP. The corresponding limits of detection (LOD) are 1.0 mM and 0.04 mM (S/N = 3) for CV and AP, respectively. Both linear range and sensitivity of the prepared sensor were enhanced through the combination of chalcopyrite and CB. The practicality of the proposed sensor was further tested by measuring H₂O₂ in real samples. Additionally, the prepared sensor showed good selectivity to H₂O₂, resisting interference from other potential interferent compounds (e.g., glucose, fructose, urea, catechol, and common metal ions), and the sensor possesses acceptable long-term stability.