Development of an amperometric sensor for epinephrine determination using an Azure A/silver nanocluster modified electrode

A novel electrochemical sensor was developed for the detection of Epinephrine (EP) utilizing Azure A (AzA), a phenothiazine dye, and citrate-capped silver nanoparticles. The interaction between Azure A and silver nanoparticles facilitated the formation of AzA/silver nanoclusters through a self-assembled approach. The morphological analysis of AzA/silver nanoclusters was conducted using field-emission scanning electron microscopy (FESEM). The nanoclusters were then immobilized on a graphite electrode via a simple drop-casting method, resulting in a modified electrode. The electrochemical properties of the modified electrode were investigated using cyclic voltammetry and linear sweep voltammetry techniques. The modified electrode exhibited enhanced electrocatalytic oxidation of EP at a lower oxidation potential of 0.27 V. The electrochemical analysis demonstrated that the modified electrode functioned as an amperometric sensor, enabling the detection of EP within a concentration range of 4.6 × 10^–7 to 3.6 × 10^–3 M, with a correlation coefficient of 0.9950 and a detection limit of 2.2 × 10^–7 M (S/N = 3). The modified electrode exhibited excellent selectivity, sensitivity, and a remarkably low detection limit, making it highly suitable for EP determination. Its ease of preparation further adds to the practicality and potential applications of this electrode.