Abstract
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•GQDs-SiNPs nanocomposite was synthesized by an ultrasonic method.•GQDs were introduced over the surface of SiNPs through amide linkage.•The GQDs-SiNPs/GC electrode provided high activity towards GSH sensing.•The GQDs-SiNPs/GC electrode proved to have a low detection limit for GSH detection.•A synergistic effect between GQDs and SiNPs enhanced GQDs-SiNPs/GC sensitivity.•The GQDs-SiNPs/GC sensor showed excellent performance when interferents are present.•High recovery yield was obtained in real sample analysis of GSH.
Glutathione (GSH) is the most abundant antioxidant in the majority of cells and tissues; and its use as a biomarker has been known for decades. In this study, a facile electrochemical method was developed for glutathione sensing using voltammetry and amperometry analyses. In this study, a novel glassy carbon electrode composed of graphene quantum dots (GQDs) embedded on amine-functionalized silica nanoparticles (SiNPs) was synthesized. GQDs embedded on amine-functionalized SiNPs were physical-chemically characterized by different techniques that included high resolution-transmission electron microscopy (HR-TEM), X-ray diffraction spectroscopy (XRD), UV–visible spectroscopy, Fourier-transform infrared spectroscopy(FTIR), and Raman spectroscopy. The newly developed electrode exhibits a good response to glutathione with a wide linear range (0.5–7 µM) and a low detection limit (0.5 µM) with high sensitivity(2.64 µA µM−1). The fabricated GQDs-SiNPs/GC electrode shows highly attractive electrocatalytic activity towards glutathione detection in the neutral media at low potential due to a synergistic surface effect caused by the incorporation of GQDs over SiNPs. It leads to higher surface area and conductivity, improving electron transfer and promoting redox reactions. Besides, it provides outstanding selectivity, reproducibility, long-term stability, and can be used in the presence of interferences typically found in real sample analysis.