Amperometric determination of hydrogen peroxide in pickling baths for copper and copper alloys by flow injection analysis

The hydrogen peroxide is oxidized at + 1.5 V vs. SCE at a glassy carbon electrode of the wall-jet type. The samples are diluted about 100 times in a dispersion coil before entering the amperometric detector. The calibration curve is linear from 10^?4 to 1 M H₂O₂, when 5-μl samples are used. With 50-μl samples the detection limit decreases to 10^?6 M H₂O₂. Neither metal ions (Cu²⁺, Zn²⁺, Ni²⁺, Al³⁺) up to 0.5 M nor changes in the sulfuric acid concentration of the samples between 0.1 and 1 M interfere with the hydrogen peroxide determination. About 75 samples can be analyzed per hour.