Detection of picomole levels of hydroperoxides using a fluorescent dichlorofluorescein assay

A highly sensitive fluorometric method for the quantitation of cholesterol, lipid, and other hydroperoxides at the picomole level is described. The method is based on the oxidation of dichlorofluoroscin to the fluorescent dichlorofluoroscein by hydroperoxide and hematin under mild conditions. A 1:1 stoichiometry is observed between the hydroperoxide added and the dichlorofluoroscein produced. Since endoperoxides (e.g., PGH2) do not react in the assay, they do not interfere in the determination of lipid hydroperoxides.