Determination of Peroxides in Environmental Samples by High Performance Liquid Chromatography with Fluorescence Detection

A high performance liquid chromatographic HPLC method with fluorescence detection was developed for the determination of hydrogen peroxide and organic peroxides in environmental samples and the method has been applied to peroxides detection in urban air and rain samples. The analytical sensitivity was improved. Post-column derivatization involved the oxidation of peroxides to a fluorescent dimer using p-hydroxyphenylacetic acid a reaction catalyzed by hemin. The optimal excitation wavelength was 315 nm while the emission wavelength was 400 nm. The temperature of the reaction coil was controlled at about 30 degrees C. Based on the ratio of signal to noise of 3 the detection limits were 4. 0 x 10(-9) mol/L for hydroperoxide H2O2 4. 1 x 10(-8) mol/L for methylhydroperoxide MHP and 6. 7 x 10(-8) mol/L for ethylhy-droperoxide EHP for aqueous samples. While the corresponding detection limits were 2. 4 ng/m(3) for H 2 0, 35. 2 ng/m(3) for MHP and 74. 4 ng/m(3) for EHP for air samples. Air samples were collected by Horibe cold trap at the temperature of about - 90 degrees C. The results show that H2O2 hydroxymethyl hydroperoxide HMHP MHP and EHP were the major peroxides in air and that peroxyacetic acid PAA was occasionally detected. In rain samples the two major peroxides were H2O2 and HMHP.