Enhanced electrochemical analysis of caffeic acid and riboflavin at amino acid modified sensor

Abstract In this study, a poly-glycine (PG)-modified carbon paste electrode (PGMCPE) is proposed as a highly sensitive electrochemical sensor for the determination of caffeic acid (CFA). To compare PGMCPE with BCPE, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and differential pulse voltammetry (DPV) were used. The scan rate, pH, and concentration of the analyte were also optimized to enhance the efficiency of the sensor. In addition to CFA, the electrode was tested for its ability to act as a multi-analyte sensor by detecting riboflavin (RF) simultaneously. The sensor was able to detect up to 0.105 µM of limit of detection (LOD) and 0.350 µM of limit of quantification (LOQ) in the linear range of 0.2–6.5 µM. The sensitivity of the sensor was then tested using an apple juice sample, and the recovery rates were high. These results indicate that PGMCPE is a suitable and effective electrochemical electrode for the analysis of CFA in real samples. Graphical Abstract