A novel electrochemical sensor based on an Fe–N–C/AuNP nanohybrid for rapid and sensitive gallic acid detection

Abstract

In this study, an Fe–N–C/AuNP nanohybrid was combined with a glassy carbon electrode (GCE) to construct a novel electrochemical sensor for rapid detection of gallic acid (GA). The synthesized materials and corresponding sensors were characterized using various physical and electrochemical techniques. Density functional theory (DFT) calculations showed that Fe–N–C nanocomposites can provide an electronic transmission channel for GA detection, while AuNPs with excellent electrical conductivity can significantly accelerate the electron transfer rate between the prepared materials and the target analyte. The Fe–N–C/AuNP nanohybrid provided the advantages of rapid electron transfer, more active sites, excellent catalytic activity, and high conductivity. Under optimal conditions, the Fe–N–C/AuNP/GCE sensor exhibited excellent performance to detect GA with a linear response range of 5–500 μM and a detection limit of 1.284 μM (S/N = 3), which illustrated its wide detection range, high sensitivity, and low detection limit. Furthermore, the constructed sensor was also effectively used to detect GA in honey, black tea and green tea samples with satisfactory recoveries (97.22–102.28%). Overall, unique modified electrode materials were investigated in this study for fabricating electrochemical sensors.