Biosynthesis of carbon quantum dot nanocomposite as an advanced material for simultaneous electrochemical sensing of D-glucose and paracetamol

Biosynthesis of carbon-based materials via pyrolysis and hydrothermal methods have emerged as a cost-effective strategy towards fabrication of biosensors for electrochemical sensing applications. The porosity, surface area and active sites on bio-derived carbon materials greatly influence the electrochemical sensing performance of modified electrodes. Herein, we report synthesis of carbon quantum dots by pyrolysis of Halimeda Opuntia green algae and doping with silver nanoparticles (AgNPs@CQDs) for the fabrication of electrochemical sensing platform of D-glucose and paracetamol. The structural and morphological features of AgNPs@CQDs were analyzed using SEM, XRD, FTIR and UV-Vis spectroscopy. Simultaneous determination of D-glucose and paracetamol in 1M KOH solution was performed using GCE-modified AgNPs@CQDs. The cyclic voltammetry confirms excellent electrochemical performance of GCE-modified AgNPs@CQDs electrodes. AgNPs@CQDs composites electrodes show improved sensing response in the pH range 4-7 with optimum values at pH = 7 for both D-glucose and paracetamol. The GCE modified by AgNPs@CQDs electrodes exhibit highly linear response for both D-glucose and paracetamol. Limit of detection was found to be 0.32 mu M and 0.29 mu M for D-glucose and paracetamol, respectively. The GCE-modified AgNPs@CQDs composites electrodes show fast response time of 33 s and 21 s, respectively, for D-glucose and paracetamol at a concentration of 10 mu M. Furthermore, the AgNPs@CQDs composites electrodes show highly selective response towards D-glucose and paracetamol against various other target analytes. Due to ease of bio synthesis, low-cost fabrication, excellent electrochemical performance towards detection of D-glucose and paracetamol, the AgNPs@CQDs could be a potential material to fabricate versatile sensors towards simultaneous determination of D-glucose and paracetamol.