Chemically renewable SERS sensor for the inspection of H₂O₂ residue in food stuff

Hydrogen peroxide (H₂O₂) residue in foodstuffs will bring great harm to human health. We immobilize the composite of the reduced polyaniline (PANI_R) modified gold nanoparticles on the surface of ITO (ITO/AuNPs/PANI_R) to develop surface-enhanced Raman scattering (SERS) sensor for H₂O_2.detection. The principle is that PANI_R is oxidized by H₂O₂ to generate a new SERS peak at 1460 cm^-1 for realizing quantitative analysis of H₂O₂. Fe²⁺-Fenton reaction is introduced to catalytically react with H₂O₂ to hydroxyl radical, which speeds up the oxidation of PANI_R. Before SERS detection, acidic treatment could guarantee the reduced state of PANI_R in composite. Limit of detection of ITO/AuNPs/PANI_R-based SERS assay for H₂O₂ is down to 1.78 × 10^-12 mol/L and a good linear relationship from 1 × 10^-10 to 3.16 × 10^-7 mol/L is achieved. Furthermore, the SERS sensor could be regenerated by acidic treatment. As a scenario, the renewable SERS sensor is utilized to monitor H₂O₂ residues in food and environmental samples.