Phloroglucinol/activated carbon composite/multiwalled carbon nanotubes modified glassy carbon electrode for electrochemical quantification of caffeic acid

Abstract

Waste-derived carbon materials and their composites have recently been utilized in electrochemical sensing of biologically important analytes due to their distinctive properties. Here, we present the electrochemical sensing of caffeic acid (CA) based on a phloroglucinol/ activated carbon composite (derived from mosquito repellent carbon rod)/multiwalled carbon nanotubes modified glassy carbon electrode (PL/AC/MWCNT/GCE). The hydrothermal process was employed to prepare activated carbon composite from waste carbon rods used in mosquito repellents. Thus obtained activated carbon composite was combined with multiwalled carbon nanotubes and electrochemically modified with phloroglucinol. Further, the prepared sensor was used effectively for electrochemical analysis of CA. The prepared electrodes are characterized using Field emission scanning electron microscope (FESEM), Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and voltammetric methods. The PL/AC/MWCNT/GCE gives an enhanced electrochemical signal for CA in contrast to the lowest modified electrodes. Electrochemical studies such as impact of scan rate, pH, catalyst loading, coating cycles and concentration were performed using cyclic voltammetric (CV) technique. Under the optimized electrochemical conditions, the PL/AC/MWCNT/GCE was used to plot the calibration curve for CA using amperometry and square wave voltammetry (SWV) techniques in the analyte concentration ranging from 0.02 to 0.2 µM and 0.01 to 0.1 µM, which resulted in lesser Limit of detection (LOD) of 36.4 nM and 4.490 nM, respectively. Finally, the prepared sensor was applied for electrochemical quantification of CA in real-time analysis using commercially available coffee and wine samples with exceptional results.