Electrochemical Behavior of Epinephrine at a Penicillamine Self-Assembled Gold Electrode, and its Analytical Application

Abstract.

The fabrication and electrochemical characteristics of a penicillamine (PCA) self-assembled monolayer modified gold electrode were investigated. The self-assembled electrode shows obvious electrocatalytic activity for the oxidation of epinephrine (EP). In phosphate buffer (pH 7.73), a sensitive oxidation peak was observed at 0.190 V with the PCA modified Au electrode. The peak current is proportional to the concentration of EP in the range of 2.0 × 10⁻⁵ ∼6.0 × 10⁻⁴ mol L⁻¹ and 5.0 × 10⁻⁶ ∼ 2.0 × 10⁻⁴ mol L⁻¹ for cyclic voltammetry (CV) and differential pulse voltammetry (DPV) with the detection limits of 1.8 × 10⁻⁷ and 1.3 × 10⁻⁷ mol L⁻¹, respectively. The possible reaction mechanism is also discussed. The PCA self-assembled monolayer modified gold electrode is highly stable and can be applied to the determination of EP in practical injection samples. Application is simple, rapid and produces accurate results.