Determination of caffeine content in tea based on poly(safranine T) electroactive film modified electrode

► PST/Nafion/GCE showed promising electrocatalysis toward the oxidation of caffeine. ► This method has wide linear range, low detection limit and high selectivity. ► This method is environment-friendly and low-cost. ► It was the first report about the electroanalytical application of PST. Safranine T was electropolymerised on a glassy carbon electrode and then characterised by scanning electron microscope (SEM), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS). This uniform electropolymerised film was crystallisable and showed a high electrocatalytic ability towards the oxidation of caffeine. To avoid the interferences of the anions, Nafion was covered on the surface of poly(safranine T) film modified glassy carbon electrode. As a new voltammetric sensor, this modified electrode is sensitive, selective and stable to determine caffeine content in tea. The peak current increased linearly with the concentration of caffeine in the range of 3×10−7–1×10−4M, with a detection limit of 1×10−7M. All of these make it a useful tool for determining caffeine content in tea. What’s more, it produces much less organic waste compared with other analytical techniques.