Peroxidase Mimic Sulfur‐Rich CuO‐Carbon Nitride Core‐Shell Nanorods for the Colorimetric Detection of Aminophenol Isomers

Abstract

AbstractA solid‐state method was used to derive a sulfur rich CuO‐carbon nitride core‐shell nano‐composite from a Cu‐organic hybrid. The synthesized material was characterized by XRD, morphology by SEM and TEM. Elemental analysis was investigated using EDS. The novel sulfur rich CuO‐carbon nitride core‐shell composite demonstrated as peroxidase activity for the oxidation of aminophenol isomers in the presence of H2O2. The oxidized products of o‐aminophenol (o‐AP) and p‐aminophenol (p‐AP) in phosphate buffer (PB, pH 7) showed strong absorption peaks at 435 and 475 nm, respectively in the UV‐Visible spectra. Whereas no oxidation reaction was observed for m‐aminophenol. Kinetic analysis of sulfur rich CuO‐graphitic carbon nitride revealed that the catalyst functioned by a ping‐pong mechanism for the oxidation of both o‐AP & p‐AP by hydrogen peroxide (H2O2). Based on KM values, substrate affinities were in the order o‐AP>H2O2>p‐AP. We further used this material for selective colorimetric detection of o‐AP and p‐AP in PB pH 7. The linear ranges obtained for o‐AP and p‐AP were 1–200 μM (LOD=1.5 μM, r2=0.99) and 10–500 μM (LOD=2.27 μM, r2=0.99), respectively. The developed analytical platform was used to detect these isomers in river water and p‐AP in artificial urine.