Keywords: PEDOT sensors, poly–3,4–ethylenedioxythiophene, sensor design, antioxidants, cyclic voltammetry, conducting polymers, glassy carbon electrodes, polymerisation, nanotechnology
Designing PEDOT–based sensors for antioxidant analysis
Antioxidants play important roles in food quality and the protection and promotion of human health. The most commonly used antioxidant determination techniques are the Folin–Ciocalteu assay and HPLC analyses. However, these methods have various disadvantages such as long time requirements, low sensitivity, interfering agents etc. Cyclic voltammetry at inert electrodes is another method for antioxidant determination. Although this method is easy to apply and gives rapid results, it is not sensitive enough to analyse many beverage antioxidants. In this study, the detection of antioxidants was achieved by covering the electrode with a poly–3,4–ethylenedioxythiophene (PEDOT) film. Polymerisation was performed electrochemically with 0.1 M 3,4–ethylenedioxythiophene (EDOT) and 0.1 M lithium perchlorate in propylene carbonate using cyclic voltammetry at 1 mm dia. electrodes. Glassy carbon and gold electrodes substrates were tested and better results were obtained with the glassy carbon electrode. Polymerisation was performed using different potential ranges and the number of cycles was varied in order to find the optimum conditions. The optimum potential range was determined to be cycling between −300 mV and 1200 mV, and one to four cycles were applied to grow the films. Green tea and catechin solutions were used as test standards. Well defined peaks for antioxidants in solution were obtained with PEDOT electrodes prepared by four preparative cycles.