ELECTROCHEMICAL DETECTION OF CAFFEIC ACID IN GREEN TEA

Abstract

One of the representatives of phenolic acids with potential carcinogenic properties is caffeic acid (CA), which is frequently found in red wines, coffee, olive oil, and some fresh fruits and vegetables. Understanding that the qualitative and quantitative study of CA in our everyday diet is of great significance. For the purpose of detecting caffeic acid, an enzymatic electrochemical biosensor was designed. In this study, we synthesized a nanocomposite comprising graphitic carbon nitride and copper sulphide for the electrochemical detection of caffeic acid. Thermogravimetric analysis, energy dispersive X-ray spectroscopy, X-ray diffraction, FTIR spectroscopy, and field emission scanning electron microscopy were used to systematically characterize and confirm the morphology, composition, and structure of the resulting nanocomposites. As expected, in comparison with the bare electrode the nanocomposite-modified electrode showed significantly higher charge transfer efficiency and electro-catalytic activity to the oxidation of caffeic acid (CA). The electrochemical and analytical techniques used for the oxidation of caffeic acid were cyclic voltammetry and chronoamperometry. The study revealed that under optimized conditions, the nanocomposite-modified ITO electrode showed a broad linear range of 1–100 µM with 0.37 µM as the lowest limit of detection for CA detection. Moreover, results indicated that the composite-modified electrode offered good sensitivity, superior reproducibility, selectivity, long-term stability, and excellent anti-interference capabilities, and it is ready for use in the real sample analysis. The fabricated enzymatic biosensor seems like a good real sample candidate for quality control analysis. Since, it effectively demonstrated its capacity to directly identify CA in commercially accessible coffee products, wine, fruit, etc. without any pretreatment. These outcomes give insightful information about the development of novel modified electrodes based on two-dimensional metal sulfide nanocomposites for high-performance electrochemical biosensor.