Flow injection determination of hydrogen peroxide using a carbon paste electrode modified with a manganese dioxide film

A manganese dioxide film modified carbon paste electrode was developed for use as an amperometric sensor for the determination of hydrogen peroxide (H2O2) in ammoniacal aqueous solutions. The electrode Showed a stable response towards H2O2 after electrochemical activation. Effects of flow rate, operating potential, concentration, injection volume and interferences were investigated. A linear response towards H2O2 from 5 μg.1-1 to 450 mg. 1-1 and a detection limit (3 signal-to-noise ratio) of 4.7 μg.1-1 was found. The method was employed for the determination of H2O2 in rain water samples.