Electrochemical determination of the synthetic antioxidant propyl gallate in foodstuffs using a graphene, gold nanoparticles, and poly(L-serine)-based sensor.

In this study, an electrochemical sensor based on graphene (GR)-, gold nanoparticles (AuNPs)-, and poly(L-serine) (PSer)-modified glassy carbon electrode (GCE) was reported for the efficient determination of the synthetic antioxidant propyl gallate (PG) in foodstuffs. The surface composition of the working electrode was optimized using the one-factor-at-a-time method. The surface morphology of the PSer/AuNPs/GR/GCE was examined using the scanning electron microscopy (SEM) technique. To evaluate the electrochemical characteristics of the sensor, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies were carried out. Linear range, detection limit, and sensitivity of the PSer/AuNPs/GR/GCE were determined by differential pulse voltammetry (DPV) and found to be 6.1 × 10-7-5.7 × 10-5 M, 1.0 × 10-7 M, and 152.4 µA mM-1, respectively. Moreover, the sensor demonstrated high fabrication reproducibility and good operational stability. The PSer/AuNPs/GR/GCE was successfully utilized to determine PG in olive oil samples, and recoveries between 100 and 102% were obtained. Moreover, the obtained results showed good agreement with HPLC analysis demonstrating the applicability of the developed sensor for PG determination in foodstuffs.