Fabrication of layer-by-layer deposited lms containing carbon nanotubes and poly(malachite green) as a sensor for simultaneous determination of ascorbic acid, epinephrine, and uric acid

A simple approach to constructing a double-layer voltammetric sensor is described. The poly(malachite green) (PMG) and multiwalled carbon nanotubes (MWCNTs) were coimmobilized at the surface of the glassy carbon electrode (GCE) for fabrication of PMG/MWCNT/GCE. The modied electrode was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), di erential pulse voltammetry (DPV), and chronoamperometric techniques. Using DPV, the obtained catalytic peak current was linearly dependent on the ascorbic acid (AA), epinephrine (EP), and uric acid (UA) concentrations in the ranges of 0.4{100.0, 0.1{100.0, and 0.3{90.0 μM, respectively. The resultant detection limits for AA, EP, and UA were 0.23, 0.0820, and 0.12 μM, respectively. The modifed electrode showed good sensitivity, selectivity, and stability and was applied to the determination of AA, EP, and UA in real samples.