Fabrication of graphene nanoribbon-based enzyme-free electrochemical sensor for the sensitive and selective analysis of rutin in tablets

Abstract

Graphene nanoribbon (GNR) is a potential sensor material owing to its high surface area, high aspect ratio, variable band gap, and high density of reactive edges. Herein, for the first time, we propose a binder-free and non-enzymatic sensor for the detection and electro-analysis of rutin using GNRs. GNRs were first synthesized from multi-walled carbon nanotubes (MWCNTs) by chemical unzipping in an oxidative environment and later casted onto graphite (Gr) electrode to get Gr/GNRs sensor. The developed sensor exhibited excellent electrocatalytic activity towards oxidation of rutin in phosphate-buffered solution (PBS) with a pair of well-defined redox peaks for rutin. Cyclic voltammetry (CV) studies showed linear dependence of sensor response on the scan rate (R2 = 0.992) and the electrode reaction occurred via diffusion-controlled charge transfer mechanism. Differential pulse voltammetry (DPV) measurements showed the existence of linear correlation between sensor response and the concentration of rutin with a detection limit of (LOD) 7.862 nM and sensitivity of 917.23 μA μM−1 cm−2. Further, the sensor showed good stability and selectivity which are attributed to synergic effects of GNRs as a sensing material. The proposed sensor was tested for its practical applicability by successfully analyzing rutin content in pharmaceutical rutin tablets which suggest that the proposed sensor can find application in the analysis of rutin in food, drug tablets, and neutraceutical samples.