Development of an electrochemical nanosensor for the determination of gallic acid in food

In the present work, a silver nanoparticle/delphinidin modified glassy carbon electrode (AgNP/Delph/GCE) was fabricated as a highly sensitive electrochemical sensor for gallic acid (GA) determination. Cyclic voltammetry experiments indicated a higher sensitivity and better selectivity for gallic acid when using the AgNP/Delph/GCE as compared with the bare GCE surface, which were attributed to AgNPs and delphinidin, respectively. Moreover, the calculated surface electron transfer rate constant ( k s ), and the electron transfer coefficient ( α ) between the GCE and the electrodeposited delphinidin demonstrated that delphinidin is an excellent electron transfer mediator for the electrocatalytic process. The average catalytic rate constant ( k ′) of the overall process was also estimated to be 7.40 × 10 −4 cm s −1 for the AgNP/Delph/GCE in the presence of 1.50 mmol L −1 of GA. Amperometry experiments were used to determine the limit of detection of the AgNP/Delph/GCE electrochemical sensor, which was 0.28 μmol L −1 of GA. Finally, two linear ranges were found, i.e. 0.60-8.68 μmol L −1 and 8.68-625.80 μmol L −1 for GA. The activity of the modified electrode was eventually investigated to assess the potential quantification of GA in real foods. In the present work, a silver nanoparticle/delphinidin modified glassy carbon electrode (AgNP/Delph/GCE) was fabricated as a highly sensitive electrochemical sensor for gallic acid (GA) determination.