Abstract: The application was studied of a detection cell with an enzyme immobilized on carbon fiber as an amperometric electrode in an organic flow stream. Peroxidase or monophenol monooxygenase was adsorbed onto the fiber to form the electrode which was operated with a Pt auxiliary electrode vs. Ag - AgCl as reference. The test analytes were 2-butanone peroxide, dodecanoyl peroxide and p-cresol and carrier electrolytes were 0.1 M tetraethylammonium p-toluenesulfonate in either CHCl3 saturated with phosphate buffer (pH 7.4) or aqueous 95% acetonitrile. Results obtained are presented and discussed and applications are proposed.

Abstract: The development and characteristics of a reagentless amperometric organic phase enzyme electrode (OPEE) employing covalently attached horseradish peroxidase and an electrochemically deposited ferrocene-modified polyaniline film on a glassy carbon electrode is reported. The covalent attachment of ferrocene to an electrochemically deposited insoluble polymer film provided a mechanism of preventing the leaching of ferrocene into the predominantly organic solvents, required for construction of reagentless OPEE. Hydrodynamic voltammetry studies showed that the response of the OPEE to hydrogen peroxides increased at higher cathodic potentials; however, interference due to molecular oxygen also increased. Interference of molecular oxygen was minimized when the OPEE was operated at an applied potential of -50 mV (or less negative) vs Ag/AgCl. The cathodic response of the OPEE was found to increase steeply when the aqueous buffer content of the acetonitrile was increased from 0 to 5 and then plateau with no further increase when the buffer content was increased to 30. The dynamic properties of this enzyme electrode were exploited for the detection of micromolar concentrations of different peroxides in flow injection analysis where the sensitivity trend was lauroyl peroxide > hydrogen peroxide > 2-butanone peroxide > cumene hydroperoxide > tert-butyl hydroperoxide. Applicability of the enzyme electrode for measurement of peroxide in real sample was demonstrated. Copyright 1995, American Chemical Society.

Abstract: Iron phthalocyanine (2%) was incorporated into carbon paste to form an electrode that could be used in 0.05 M phosphate buffer at pH 2 for the amperometric detection of organic peroxides (excluding dialkyl peroxides) at +0.1 V (minimum) vs. Ag/AgCl. Detection limits (pmol) measured for operation at +0.35 V ranged from 0.13 for peracetic acid to 300 for 1-[(1-hydroperoxycyclohexyl)dioxy]cyclohexanol. No response was shown for a 500-pmol injection of t-butyl peroxide, but the detection limit was 1.0 pmol for 2-butanone peroxide. The method was suitable for use in FIA or HPLC and 10% acetonitrile could be added to the mobile phase.