The efficiency of an aminated nanocrystalline cellulose stabilized binary Ag–ZnO nanocomposite as an electrode platform for electrochemical sensing of ascorbic acid

Abstract

This work details the fabrication of a graphite coated aminated nanocrystalline cellulose stabilized Ag–ZnO nanocomposite electrode for application in electrochemical sensing and quantification of ascorbic acid (AA) in biological samples. The prepared nanocomposite is named ANCC/Ag–ZnO, where ANCC stands for aminated nanocrystalline cellulose. The graphite coated ANCC/Ag–ZnO electrode produced a high electrochemical response because of binary Ag–ZnO nanoparticles and the stability, high surface area, porosity, and crystallinity of nanocellulose. The ANCC particles are prepared by amination of nanocrystalline cellulose (NCC), with the latter being synthesized from raw rice (Oryza sativa) straw. The green ethanol extract from mussaenda flower (M. erythrophylla) bracts is used as a reducing agent to generate Ag–ZnO nanoparticles. The average diameter of a spherical ANCC/Ag–ZnO nanocomposite is around 9.77 nm. The graphite coated ANCC/Ag–ZnO nanocomposite electrode demonstrated an 8 times increase in cyclic voltammogram (CV) current response compared to the native graphite coated ANCC electrode. The electrocatalytic oxidation of AA showed a good linearity over a wider range of 0–16.0 mM with a regression value of 0.9934. The sensitivity and limit of detection (LOD) are 0.543 mA mM⁻¹ cm⁻² and 0.031 mM, respectively, and the electrode possessed a good reproducibility (RSD, 2.06%). The nanocomposite electrode retained about 81% of its initial current response after 1500 cycles. The synthesized ANCC/Ag–ZnO nanocomposite material is found to be applicable for electrochemical sensing and quantification of AA in biological samples without overlapping signals from other interfering agents.