Fabrication, characterization and application of a grafting based gold nanoparticleselectrode for the selective determination of an important neurotransmitter

Abstract

β-D-Glucose capped gold nanoparticles (Glu-AuNPs) were synthesized and then immobilized on an aminophenyl grafted GC electrode for the selective determination of norepinephrine (NEP) in the presence of uric acid (UA). 1,4-Diaminobenzene (DAB) was used to graft the GC surface and the resulting grafted GC electrode was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and impedance spectroscopy. Glu-AuNPs were immobilized on a grafted GC electrode (Glu-AuNPs electrode) and it was confirmed by SEM, UV-visible spectroscopy and electrochemical techniques. Impedance studies show that the electron transfer reaction of [Ru(NH₃)₆]^3+/2+ was higher at the Glu-AuNPs electrode (7.49 × 10⁻⁴ cm s⁻¹) than at bare (5.64 × 10⁻⁴ cm s⁻¹) and grafted (1.67 × 10⁻⁶ cm s⁻¹) GC electrodes. The Glu-AuNPs electrode shows an excellent electrocatalytic activity towards NEP and UA when compared to grafted and bare GC electrodes. Further, the Glu-AuNPs electrode was successfully used for the selective determination of NEP in the presence of 50-fold excess UA at physiological pH.