Detection of caffeic acid using a nanotube paste-based electrochemical sensor

Abstract

In the present study, electrochemical sensing electrode based on uniform poly(arginine)-modified carbon nanotube paste electrode (PAMCNTPE) is introduced for concurrent determination of caffeic acid and paracetamol. Scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) were used to characterize the surface of the sensor. In addition, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the performance of PAMCNTPE. The redox optimum current of caffeic acid was increased dramatically at the PAMCNTPE surface alongside bare carbon nanotube paste electrode (BCNTPE) and their overpotentials decreased. SEM images shows the morphological differences between bare and modified electrode which shows the evidence of modification. The effects of pH, polymerization cycle, and potential were investigated on the electrochemical redox response of caffeic acid based on response surface methodology. In addition, scan rate technique showed the process is adsorption controlled. Under the optimized conditions, linear response was obtained over the range of 10–200 μM, and also, detection limits were found to be 0.13 μM by DPV method on the surface of PAMCNTPE. The PAMCNTPE showed good stability, reproducibility, and repeatability as well as high recovery. The practical application of the PAMCNTPE was demonstrated by measuring the concentration of caffeic acid in apple juice as real sample. The proposed technique is simple, rapid, and cost-effective, serving as an important analytical tool for quality control in the pharmaceutical industry.

Graphical abstract