A core-shell MWCNT@rGONR heterostructure modified glassy carbon electrode for ultrasensitive electrochemical detection of glutathione

•An electrochemical sensor based on a core-shell MWCNT@rGONR heterostructure for detection of GSH has been successfully developed.•This sensor showed excellent electrocatalytic oxidation towards GSH with low detection limits and wide linear ranges.•The application for the detection of GSH in serum samples was demonstrated with good accuracy. In this work, a multiwalled carbon nanotubes@reduced graphene oxide nanoribbons core-shell heterostructure (MWCNT@rGONR)-modified glassy carbon electrode (MWCNT@rGONR/GCE) was employed to electrochemically detect glutathione (GSH). The morphologies and microstructures of the as-prepared MWCNT@rGONR heterostructure were examined by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy spectrum (FT-IR), respectively. The electrochemical characteristics and catalytic behaviors of the fabricated sensor for determination of GSH were systematically investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and amperometry (i–t). Under optimum conditions, the MWCNT@rGONR heterostructure modified electrode possesses the ability of strong electrocatalytic for GSH with high selectivity and sensitivity, fast response, wide linear range, low detection limit (39 nM) and outstanding reproducibility. Its further application for the quantification of GSH concentration in human serum samples was also demonstrated with satisfactory accuracy. These features indicate that the prepared core-shell MWCNT@rGONR heterostructure with unique electronic structure offers an excellent biosensing platform for sensitive and selective detection of glutathione.