Interlayer-engineered graphene oxide-mono-Boc-ethylenediamine nanosheets for sensitive electrochemical detection of the food antioxidant tert-butylhydroquinone.

The monitoring of synthetic antioxidants in food products is essential for quality and consumer safety. In this work, we present the very first electrochemical sensing application of mono-Boc-ethylenediamine-functionalized graphene oxide (GO-EnBoc) nanosheets for the sensitive determination of tert-butylhydroquinone (TBHQ), a widely used food preservative. GO-EnBoc was synthesized by covalent intercalation of mono-Boc-ethylenediamine into the layers of graphene oxide and characterized by various techniques. XRD analysis revealed a significant increase in the interlayer spacing from 0.93 nm to 1.20 nm, indicating successful intercalation, and FTIR spectra confirmed the introduction of nitrogen-containing functional groups. Morphological investigations showed a wrinkled, ultrathin layered structure with improved surface accessibility and electron transfer properties. We investigated the electrochemical sensing performance of GO-EnBoc modified glassy carbon electrodes using differential pulse voltammetry (DPV). At around 0.33 V (vs. Ag/AgCl), the modified electrode presented a well-defined TBHQ oxidation peak and a linear response in the concentration range of 0.1-130 µM with a correlation coefficient of 0.99. The sensor exhibited a low limit of detection (LOD) of 95 nM and a limit of quantification (LOQ) of 0.31 µM. Good repeatability (RSD = 2.1%) and reproducibility (RSD = 3.4%) were obtained. The practical applicability of the sensor was confirmed in chips, popcorn, and edible oil samples with a recovery of 92% to 102%. These findings demonstrate GO-EnBoc as an attractive platform for rapid, reliable, and portable electrochemical monitoring of synthetic antioxidants in complex food matrices.