Fabrication of poly (Solid Red A) modified carbon nano tube paste electrode and its application for simultaneous determination of epinephrine, uric acid and ascorbic acid

In this study, a stable electroactive thin film of poly(Solid Red A) has been deposited on the surface of a carbon nano tube paste electrode by cyclic voltammetric technique in an pH 7 phosphate buffer solution (PBS) containing Solid Red A. A higher catalytic activity was obtained for electrocatalytic oxidation of ascorbic acid (AA), epinephrine (EP), and uric acid (UA) in pH 7 PBS at over oxidized poly (Solid Red A) film modified carbon nano tube paste electrode (PSRA/MCNTPE) due to an enhanced peak current and well-defined peak separations compared with both bare carbon nano tube paste electrode (BCNTPE) and PSRA/MCNTPE. The electrode surfaces were characterized by field emission scanning electron microscopy (FESEM). Individual and simultaneous determination of AA, EP, and UA were carried out by cyclic voltammetry and differential pulse voltammetry. The reduction peak current was proportional to the EP and UA concentrations in the range of 2.0 × 10−6-9.0 × 10−6 M and 7.0 × 10−6-2 × 10−5 M, respectively. The modified electrode showed good sensitivity, selectivity, stability, and was employed for the determination of EP and UA in real samples.