Rapid detection of gingerol and thymol in medicinal foods based on Fe ₂O ₃ nanoparticles modified glassy carbon electrode

Abstract

Ginger and Ajwain are used extensively in food products, natural medicine to treat certain common diseases and as an immunity booster against viral infections. In this work, we report the fabrication of a novel electrochemical sensor based on α-Fe ₂O ₃ nanoparticles for detection and quantification of [6]-Gingerol (GIN) and Thymol (THY) which are water soluble phytochemicals derived from edible herbs Ginger and Ajwain respectively. The α-Fe ₂O ₃ nanoparticles were synthesised by sol-gel method and its structure and composition were confirmed by powder X-ray diffraction and photoelectron spectroscopy studies. The α-Fe ₂O ₃ NPs modified glassy carbon electrode (GCE) exhibited an excellent electrocatalytic activity towards the oxidation of GIN and THY in phosphate buffer saline at pH 7. The α-Fe ₂O ₃ modified GCE exhibited the lowest detection limits of 35.2 nM and 24 nM for GIN and THY respectively over the corresponding dynamic ranges of 55.6 nM to 118 µM and 27.8 nM to 56 µM. Detailed interference study confirmed the potential anti-interference ability of the fabricated sensor against a number of potential interfering compounds. Cyclic stability study yielded relative standard deviation (RSD) values of 9.9% and 9.18% for GIN and THY respectively, demonstrating excellent stability of the sensor. Reproducibility of the α-Fe ₂O ₃/GCE was investigated by testing a number of electrodes which yielded RSD values of 1.08% and 0.97%, for GIN and THY respectively. These promising characteristic features of the proposed sensor make it suitable for quick and precise detection of GIN and THY in food and natural medicines.

Graphical Abstract