Determination of Trace Hydrogen Peroxide in Rain by Malachite Green-Fe(II) Catalytic Kinetic Spectrophotometric System

A new catalytic spectrophotometric method for the determination of trace hydrogen peroxide under room temperature was developed basing on the catalysis of Fe(Ⅱ) to the decoloration reaction of malachite green by hydrogen peroxide in the dilute H_2SO_4 medium(pH = 4.0).The reduced intensity(△A) of absorbance of malachite green measured at its maximum absorption wavelength 618 nm was found having good linear relationship with the concentration of hydrogen peroxide in the range of 0-50μmol · L~(-1).The regression equation of calibration curve was△A = 0.0171C+0.0191,and the detection limit(S/n = 3) was 1.0μmol · L~(-1).The proposed method is easy and rapid,and was applied to determining the hydrogen peroxide in rain water samples with satisfactory result.