Determination of peroxides by capillary zone electrophoresis with amperometric detection

The combination of cathodic amperometric detection with capillary zone elec trophoresis is demonstrated to be a versatile method for the quantification of organic and inorganic peroxides. A gold microelectrode, polarized at -6 00 mV against an Ag/AgCl reference electrode, is placed at the end of the c apillary. Since the electroosmotic flow purges the detector electrode from oxygen, no degassing of the detector cell or the sample is necessary. With an injection volume of ca. 1 nl, hydrogen peroxide, peroxosulfate, peroxy a lkanoic acids and the hydroperoxides of Linoleic acid can be detected down to 10 mu mol/l. Separation of the isomeric hydroperoxides of the unsaturate d fatty acids is achieved by addition of beta-cyclodextrin to the electroly te. (C) 2000 Elsevier Science B.V. All rights reserved.