Electrodeposition of 4-Benzenesulfonic Acid onto a Graphite-Epoxy Composite Electrode for the Enhanced Voltammetric Determination of Caffeine in Beverages

Figure 1

Typical result from the modification process (from the first to the following voltammetric cycles, until the obtainment of surface modification) with diazonium salts, in particular, the result to EL1 modification is shown. The arrow shows the scan direction and the first cycle of the process.