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

Figure 6

SWV voltammograms showing background measurement followed by 10 additions of 0.1 mL of caffeine standard and 0.1 mol·L⁻¹ for bare (dashed lines) and modified electrode (4-benzenesulfonic acid) systems. SWV parameters: 100 mV pulse amplitude, 10 mV potential step, 8 Hz frequency for bare electrode, and 12 Hz frequency for the modified one. Bare electrode curve: i = 0.0087 C − 2.45 × 10⁻⁶; r² = 0.9822. EL1 curve: i = 0.0837 + 3.51 × 10⁻⁵; r² = 0.9914.