Electrocatalytical oxidation and sensitive determination of acetaminophen on glassy carbon electrode modified with graphene-chitosan composite

The electrochemical behaviors of acetaminophen (ACOP) on a graphene-chitosan (GR-CS) nanocomposite modified glassy carbon electrode (GCE) were investigated by cyclic voltammetry (CV), chronocoulometry (CC) and differential pulse voltammetry (DPV). Electrochemical characterization showed that the GR-CS nanocomposite had excellent electrocatalytic activity and surface area effect. As compared with bare GCE, the redox signal of ACOP on GR-CS/GCE was greatly enhanced. The values of electron transfer rate constant (k(s)), diffusion coefficient (D) and the surface adsorption amount (I*) of ACOP on GR-CS/GCE were determined to be 025 s(-1), 3.61 x 10(-5) cm(2) s(-1) and 1.09 x 10(-9) mol cm(-2), respectively. Additionally, a 2e(-)/2H(+) electrochemical reaction mechanism of ACOP was deduced based on the acidity experiment. Under the optimized conditions, the ACOP could be quantified in the range from 1.0 x 10(-6) to 1.0 x 10(-4) M with a low detection limit of 3.0 x 10(-7) M based on 3S/N. The interference and recovery experiments further showed that the proposed method is acceptable for the determination of ACOP in real pharmaceutical preparations. (C) 2012 Elsevier B.V. All rights reserved.