Electrochemically Reduced Graphene Oxide as a Support for Polyaniline‐Coated Gold Nanoparticles in Non‐Enzymatic EC‐SERS Detection of Hydrogen Peroxide

Hydrogen peroxide is an important reactive oxygen species involved in oxidative stress, enzymatic reactions, food processing, and environmental monitoring; therefore, sensitive and operationally stable methods for its determination remain relevant in electroanalytical chemistry. Here, we report an enzyme‐free electrochemical surface‐enhanced Raman spectroscopy (EC‐SERS) platform based on screen‐printed gold electrodes modified with ultrathin graphene oxide (GO) or electrochemically reduced graphene oxide (ERGO) layers and polyaniline‐coated gold nanoparticles (PANI@AuNPs) as redox‐active Raman nanoprobes. H 2 O 2 was quantified indirectly using the ratiometric SERS marker I 1565 /I 1595 , which reflects the conversion of reduced/benzenoid PANI domains into oxidized/quinoid structures rather than direct detection of a characteristic H 2 O 2 Raman band. The ERGO‐based platform provided an H 2 O 2 detection limit of 8.13 × 10 −7 M and excellent linearity over the 10 −6 –10 −2 M range. Compared with the previously reported horseradish peroxidase (HRP)–assisted system, it offers an enzyme‐free alternative with simpler preparation and improved tolerance to millimolar H 2 O 2 concentrations, where the enzyme is inhibited. Preliminary matrix tolerance tests showed that the response in tap water was comparable to that in PBS, while diluted milk caused an approximately 10.5% decrease in the ratiometric signal, supporting the potential applicability of the PANI@AuNPs/ERGO platform in environmental water and selected food–related matrices.