Laser-induced UiO-66-derived ZrO2-ZrC-graphene sensor for sensitive detection of chlorogenic acid in food samples

Chlorogenic acid (CGA), a dietary polyphenol with antioxidant and therapeutic benefits, can be harmful at high concentrations, necessitating sensitive detection in food. This study presents a ZrO 2 -ZrC-doped laser-induced graphene (ZrO 2 -ZrC-LIG) electrode prepared via a one-step laser carbonization of UiO-66/polyimide film. Structural analysis reveals a three-dimensional porous network with uniformly dispersed ZrO 2 and ZrC nanoparticles in graphene, which increases defect density, conductivity and surface area. The optimal conditions of laser-induced parameters such as power and carving depth for the electrode fabrication were selected. Under the optimal conditions, the electro-oxidation of CGA on the ZrO 2 -ZrC-LIG electrode was carefully investigated with electrochemical parameters calculated. The presence of ZrO 2 , ZrC and LIG exhibited an enhancement to the CGA oxidation with a pair of well-define redox peaks appeared, which was attributed to the faster electron transfer, higher electrocatalytic activity and synergistic effects. When integrated with a wireless portable electrochemical workstation, the fabricated sensor shows excellent analytical performance for CGA detection, including a wide linear range (0.1 μM to 1.0 mM), a low detection limit of 33 nM (3σ), along with high selectivity, stability, and reproducibility. When applied to apple and Eucommia ulmoides samples, it achieves the recoveries of 99.26–103.14%, confirming good analytical reliability. This simple and scalable method offers a promising strategy for developing flexible, portable electrochemical sensors for food safety and nutrition monitoring.