Amperometric Detection Under Batch-Injection Analysis Conditions of Caffeine on an Electrode Modified by Mixed-Valence Iridium and Ruthenium Oxides

Resumo

Mixed-valence Ir–Ru oxides (IrO_x—RuO_x) electrodeposited on a glassy-carbon electrode surface were found to exhibit catalytic activity for caffeine oxidation. An amperometric method for caffeine detection at this modified electrode under batch-injection analysis conditions was developed. The analytical signal was linearly dependent on the caffeine concentration in the range 5 × 10⁻⁸ – 5 × 10⁻³ M. The developed method was tested for caffeine determination in tablets, solutions for injection of caffeine—sodium benzoate, and coffetamin tablets.