Nanogold-decorated reduced graphene oxide/chitosan composite for electrochemical sensing of N-acetyl-4-aminophenol

Abstract

In this study, a novel electrocatalyst designed by doping gold nanoparticles (AuNPs) over the reduced graphene oxide (rGO)/Chitosan (CTSN) matrix for the determination of N-acetyl-4-aminophenol, i.e. acetaminophen (AC) in phosphate buffer solution has been reported. The catalyst was synthesized via a simple ultra-sonication process followed by a photo-reduction technique to obtain 1%AuNPs@5%rGO/CTSN nanocomposite. The conductivity of the CTSN biopolymer was enhanced by coupling rGO and thereafter rGO/CTSN surface was decorated with nano-Au particles to improve the catalytic efficiency. The structural and surface properties of the as-fabricated nanocomposite have been thoroughly investigated using cutting–edge microscopic and spectroscopic techniques. The catalytic and sensing phenomena were systematically studied with several well-known electrochemical techniques. Using differential pulse voltammetry (DPV), the peak current was found to be linear across the AC concentration range of 0.50 μM–39.31 μM, with a high sensitivity of 2.358 μAμM−1cm−2 and a low limit of detection (LOD) of 0.06 μM. Moreover, under optimal experimental conditions, the amperometric (i-t) study showed a high sensitivity value of 0.935 μA μM−1cm−2, a wide AC detection range (5.0 μM–160 μM), and LOD 0.151 μM. The proposed sensor also demonstrated high selectivity in the existence of common interfering species. In addition, this newly fabricated sensor electrode exhibited admirable reproducibility, repeatability, and remarkable storage and operational stability. It was also successfully applied to AC recovery tests in real samples as a pharmaceutical formulation.