A novel carbon black-integrated cage-structured NiCo2O4 nanocomposite for the selective and sensitive electrochemical determination of vanillin.

A novel electrochemical sensor for determination of vanillin based on carbon black and NiCo2O4 nanocomposite (CB@NiCo2O4) was established. The nanocomposite was immobilized onto electrode surface, the carbon black can selectively adsorb vanillin via π-π stacking interactions between the aromatic domains and the benzene ring of vanillin. Concurrently, the NiCo2O4 with cage-structure enhances the electrochemical signal response of the adsorbed vanillin by the high specific surface area and favorable ion-exchange capability. Under optimized experimental conditions, the sensor exhibits a linear range of 0.1 ~ 60 µM with a limit of detection of 30 nM, and the selectivity and signal stability were confirmed to be satisfactory. In real-sample analysis, the results are agreement with the contrast testing results of high-performance liquid chromatography, and the spike recovery experiment values ranged from 95.35% to 103.80%, with relative standard deviations (RSDs) of 3.77%~4.59% (n = 3). The proposed electrochemical sensor possesses a favorable application prospect in product quality control.