Plasma-modified graphene oxide from sustainable carbon sources for caffeic acid detection

Caffeic acid, a common naturally occurring polyphenol found in coffee and certain fruits exhibits cytotoxic and potential carcinogenic effects at high levels. Accurate detection and reliable sensing platforms are thereby essential to assess food quality and safety. In this study, bioprecursor derived graphene oxide (GO) has been used for caffeic acid detection. The GO was synthesized from coffee husk carbon using a rapid microwave-assisted pyrolysis method, followed by RF plasma treatment to enhance its surface activity. Plasma interaction with GO targeted the π bonds on the carbon surface, generating free radicals, creating a highly energized surface with improved electrosorption capacity. The plasma-treated graphene oxide was deposited on a glassy carbon electrode, that exhibited a low detection limit of 5.47 μM/5.87 μM and a wide linear range (1–113 μM/L) for detection of caffeic acid. Repeatability, reproducibility, and stability tests confirmed the robustness of the sensor, with low RSD values around 3 %. These findings demonstrate the potential of plasma-engineered graphene oxide as a sustainable and reliable material for caffeic acid sensing, while promoting circular approaches to waste management.