Abstract
An indirect liquid chromatographic determination method for the hydroxyl radical in an aqueous system was described. The method is based on the production of methanesulfinic acid as the primary product by the reaction of hydroxyl radical with dimethyl sulfoxide. The methanesulfinic acid formed was coupled with diazonium salt to afford the diazosulfone derivative, which was detected and equantified by reversed-phase liquid chromatography at 420 nm. The practical conditions for the methanesulfinic acid detection were optimized. Linearity of the methanesulfinic acid formation was observed in the range from 0.5×10-3mM to 10×10-3 mM. To evaluate this method for estimating hydroxyl radical production, two model systems, including the Fenton reaction and ultraviolet photolysis of hydrogen peroxide were studied. The theoretical maximum yield of hydroxyl radical in the systems could be calculated and compared to the measured dimethyl sulfoxide oxidation. The estimated concentration of hydroxyl radical from 80×10-3mM of hydrogen peroxide in the Fention reaction was 7.4×10-3mM. The present method may prove useful for detecting hydroxyl radical involvement in biological samples.
