Nonenzymatic sensor for hydrogen peroxide using a carbon paste electrode modified with a composite consisting of silver nanoparticles, poly(o-aminobenzoic acid) and magnetite

A nonenzymatic hydrogen peroxide (H₂O₂) sensor using a carbon paste electrode (CPE) modified with a composite consisting of silver nanoparticles (AgNPs), poly(o-aminobenzoic acid) (P(ABA)) and magnetite (Fe₃O₄) is reported. The AgNPs-P(ABA)-Fe₃O₄ composite was prepared under sonication and characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Electrochemical investigations indicated that a carbon paste electrode modified with AgNPs-P(ABA)-Fe₃O₄ exhibits excellent performance in the electrochemical reduction of H₂O₂ at an applied potential of -0.4 V versus Ag/AgCl (sat. 3.0 M KCl) in phosphate buffer solution. Under optimum condition, the calibration curve for H₂O₂ was obtained in a wide range of 5 μM to 5.5 mM with the limit of detection (LOD) of 1.74 μM (S/N = 3). The AgNPs-P(ABA)-Fe₃O₄ modified electrode has a good stability in practical conditions. In addition, the fabricated sensor was applied to determine H₂O₂ in real samples with good results.