AMPEROMETRIC DETERMINATION OF LIPID HYDROPEROXIDES

A new amperometric analytical technique for measuring lipid hydroperox ides is described. The technique is based on the measurement of cathod ic current due to the reduction of ferricinium ion formed as result of the oxidation of ferrocene by lipid hydroperoxides. The effects of pH and applied potential were investigated to determine the optimum pH a nd working potential for the determination of linoleic acid and linole nic acid hydroperoxides. The analysis, performed in pH 5.5, 0.1 M. pho sphate buffer and at -100 mV (vs Ag/AgCl) applied potential, responded linearly to linoleic acid hydroperoxide and linolenic acid hydroperox ide up to 1.5 and 1.2 mu M, respectively. The lower detection limits w ere 20 nM for linoleic acid hydroperoxide and 25 nM for linolenic acid hydroperoxide. Reductants such as ascorbate and urate present in the biological samples, as well as other peroxides, did not interfere in t he amperometric analyses of lipid hydroperoxides. (C) 1995 Academic Pr ess, Inc.