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 lambda(em) = 440 nm (emission wavelength) with lambda(ex) = 235 nm (excitation wavelength), and the fluorescence intensity at) lambda(em) = 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 x 10(-8)-1.0 x 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 x 10(-8) mol L-1 hydrogen peroxide. The proposed FIA technique could be applied to the determination of hydrogen peroxide in rain water samples. (C) 2010 Elsevier B.V. All rights reserved.