Flow-injection determination of hydrogen peroxide based on fluorescence quenching of chromotropic acid catalyzed with Fe(II)

Flow-injection analysis system (FIA system), which was based on Fe(II)-catalyzed oxidation of chromotropic acid with hydrogen peroxide, was developed for the determination of hydrogen peroxide. The chromotropic acid has a fluorescence measured at λem = 440 nm (emission wavelength) with λex = 235 nm (excitation wavelength), and the fluorescence intensity at λem = 440 nm quietly decreased in the presence of hydrogen peroxide and Fe(II), which was caused by Fe(II)-catalyzed oxidation of chromotropic acid with hydrogen peroxide. By measuring the difference of fluorescence intensity, hydrogen peroxide (1.0 × 10−8–1.0 × 10−3 mol L−1) could be determined by the proposed FIA system, whose analytical throughput was 40 samples h−1. The relative standard deviation (RSD) was 1.03% (n = 10) for 4.0 × 10−8 mol L−1 hydrogen peroxide. The proposed FIA technique could be applied to the determination of hydrogen peroxide in rain water samples.