Kinetic fluorimetric determination of organic peroxides and lipohydroperoxides at the nanomole level

A new kinetic fluorimetric method for determination of cumene hydroperoxide, tert-butyl hydroperoxide and lipohydroperoxides is reported. It is based on the manganese(II)-catalysed oxidation of 2-hydroxynaphthaldehyde thiosemicarbazone (HNTS) by a hydroperoxide. Measurements are made by the initial-rate method, which allows determination of as little as 0.1 nmole of peroxide and also permits establishment of the differences in reactivity between the hydroperoxides assayed. The method has been applied to the determination of lipohydroperoxides in six commercial oil samples (grape, corn, sunflower seed, cod-liver and linseed). The results obtained can be expressed as meq of peroxide per kg of oil, and are in close agreement with those obtained by the classical iodometric method.