Peroxidase-like Fe₃O₄ Nanoparticle/Few-Layered Graphene Composite for Electrochemical Detection of Dopamine, Ascorbic Acid, and Uric Acid

A nano-Fe 3 O 4 /few-layered graphene (FLG) composite is prepared for ultrasensitive detection of dopamine (DA) in the presence of interfering uric acid (UA) and ascorbic acid (AA) molecules. The sensor material is prepared by a completely solid-state process. The sensor works on the synergy between the peroxidase-like behavior of nano-Fe 3 O 4 and the electrocatalytic activity of FLG to detect DA, UA, and AA with excellent sensitivity and selectivity using differential pulse voltammetry. DA is detected in two linear ranges, 3.33–19 and 23–62.3 nM, with the detection limit and quantification limit as 0.413 and 1.239 nM, respectively. The practical viability of the nano-Fe 3 O 4 /FLG-based sensor is confirmed by performing analysis using human serum and synthetic commercial drug samples. The calculated limit of detection and linear dynamic range values pertaining to the detection of DA, UA, and AA molecules through electro-oxidation in the presence of each other are also found to be excellent.