Graphite-polystyrene composite with enhanced electrochemical and electroanalytical performance.

A new composite electrode (G-PSE) was developed from graphite powder and expanded polystyrene (EPS, Styrofoam) by simply dissolving the foam in chloroform, incorporating the graphite particles under mixing and volatilizing the solvent at 80 °C. The resulting rigid black composite can be softened with acetone and so it can easily be molded to any shape, e.g., into a PTFE tube with an electric contact, to build the electrode. A 75% graphite content (w/w) was found appropriate for preparing the G-PSE with a working potential similar to that of carbon paste electrodes, superior mechanical stability and a much faster response to ferrocyanide, close to reversible and similar to that of the much more expensive glassy carbon electrode. Applications of the G-PSE to dipyrone and paracetamol quantification in pharmaceutical formulations were demonstrated. The results accomplished by flow injection analysis with amperometric detection at the G-PSE were successfully validated against standards methods.