Direct and selective determination of p-coumaric acid in food samples via layered Nb₄AlC₃-MAX phase

Phenolic compounds that are naturally found in food samples are not only an important part of the human diet but also useful bioactive substances for health. Among these, para-coumaric acid (p-CA) has antibacterial and antioxidant properties and is used in many industrial processes. In this study, the novel MAX-phase material, Nb₄AlC₃, was successfully prepared and characterized in detail with various spectroscopic, microscopic and thermal techniques. The sensor performance of Nb₄AlC₃ modified glassy carbon electrode (Nb₄AlC₃@GCE) was evaluated and analytical parameters were calculated. Experimental conditions such as pH and amount of modifier were optimized with differential pulse voltammetry (DPV) measurements. The real samples analyses of lemon, apple and pomegranate were applied for determination of p-CA with Nb₄AlC₃@GCE sensing system under the optimized conditions. The accuracy was evaluated by spike/recovery and high-performance liquid chromatography analysis, which accounted for high accuracy of the Nb₄AlC₃@GCE sensing system. The limit of detection, limit of quantification, linear working range and relative standard deviation (%) of the Nb₄AlC₃@GCE sensing system were determined as 0.28 and 0.85 µmol/L, 0.8-80.0 µmol/L, 3.17 %, respectively. The results showed that the proposed sensing system has the high precision at lower concentration of p-CA.