Determination of Dopamine by Dual Doped Graphene-Fe₂O₃in Presence of Ascorbic Acid

Both nitrogen and sulfur dual doped graphene supported Fe 2 O 3 (NSG-Fe 2 O 3 ) have been prepared by hydrothermal methods and subsequently utilized for the electrochemical determination of dopamine (DA) in presence of ascorbic acid (AA). The NSG-Fe 2 O 3 has been characterized via transmission electron microscopy (TEM) and X-ray photoelectron spectroscopic (XPS). The electrochemical detection of DA was measured through the cyclic voltammetry, differential pulse voltammetry, and amperometric techniques in a 0.1 M phosphate buffer solution (PBS) at pH 7.4. Interferences have been investigated in presence of AA, glucose, serotonin, N 2 H 4 , and uric acid. The NSG–Fe 2 O 3 has shown good analytical performance for DA with comparatively better sensitivity (29.1 μA mM −1 ), long linear detection range (0.3–210 μM) and detection limit (0.035 μM) ( S/N = 3). The catalytic rate constant for DA detection has been calculated as 9.6 × 10 4 M −1 s −1 with a good diffusion coefficient of 3.5 × 10 −4 cm 2 s −1 . The electrooxidation of DA may enhances by fast proton acceptance and/or electron donation due to higher electron density for excess loan pair electron that provided from N and S dual-doped graphene sheets.