Electrocatalytic oxidation of dopamine on the surface of ferrocene grafted hydroxyl terminated polybutadiene modified electrode

Abstract

In this study, 4-(dimethylsilyl)butylferrocene was prepared using 4-chlorobutylferrocene via Grignard reaction in dry THF and the reaction of prepared reagent with chlorodimethylsilane. In continue, obtained ferrocenylsilane derivative was grafted to hydroxyl terminated polybutadiene (HTPB) via hydrosilylation reaction. Ferrocenyl units in polymer backbone gave a couple of reversible peaks of cyclic voltammetry (CV). Additionally, FT-IR, 1H NMR, UV–Vis spectroscopy along with molecular weight and TGA analysis confirmed the polymer modification. The modified polymer was coated onto the surface of glassy carbon electrode (GCE); meanwhile, fresh egg white (FEW) and terephthaldehyde (TFA) were used as cross-linking agents. The successful immobilization of polymer was demonstrated using Electrochemical impedance spectroscopy (EIS). The modified electrode showed an electrocatalytic effect on the oxidation of DA, the Fc/Fc+ couple mediate the oxidation of DA on the surface of GC/Butacene/(TFA + FEW) electrode. The optimum pH = 7 was obtained for this response. The electrode protected 86% of its initial electrocatalytic after 500 cycles and 90% of its initial current after 30 day storage at 4 °C. The results indicated that GC/Butacene/(TFA + FEW) electrode possessed satisfactory linear ranges and detection limits for detection of DA.