A biosensor based on a graphene nanoribbon/silver nanoparticle/polyphenol oxidase composite matrix on a graphite electrode: application in the analysis of catechol in green tea samples

Abstract

The present report demonstrates the development of a highly sensitive and selective electrochemical biosensor for catechol detection by immobilizing crude polyphenol oxidase (PPO) enzyme onto a graphite (Gr) electrode modified using graphene nanoribbons (GNRs) decorated with green synthesized silver nanoparticles (AgNPs). The developed electrochemical sensor, Gr/GNRs/AgNPs/PPO, is characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques at each stage of its fabrication. Under the optimized conditions, the developed sensor showed excellent electrocatalytic activity towards the detection of catechol which is attributed to higher electron transfer rates induced due to incorporation of GNRs and AgNPs in the electrode matrix. The sensor exhibited a wide detection range (2–2300 μM) and low detection limit. The sensor also showed superior selectivity towards catechol detection in the presence of common interferents. Furthermore, the efficiency of the catechol biosensor in real sample analysis is validated by analyzing catechol in different tea samples. The results of electroanalysis in comparison with high performance liquid chromatography (HPLC) results showed good agreement suggesting that the developed GNR composite based catechol sensor is efficient enough to be employed in detection and quantification of catechol in real samples, particularly the analysis of tea samples.