Horseradish peroxidase-based organic-phase enzyme electrode.
An organic-phase enzyme electrode (OPEE) based on horseradish peroxidase (HRP) immobilized within Nafion on spectroscopic graphite was investigated in acetonitrile. The amperometric electrode response to hydrogen peroxide and cumene hydroperoxide present was found to be the result of the reduction of oxygen, produced upon enzymatic decomposition of both hydroperoxides (i.e., by the catalase-like activity of HRP). The electrode response was found to depend linearly on the hydroperoxide concentration up to 700 microM within the range of potentials from -200 to -400 mV (versus Ag|AgCl). Detection limits of approximately 45 microM for H2O2 and 100 microM for cumene hydroperoxide were determined under the selected experimental conditions. Nernstian dependence (the open circuit voltage of HRP-based electrode versus logarithm of H2O2 concentration) was obtained between 0.2 and 2.0 mM, with a slope of approximately 23 mV per logarithmic unit, suggesting a catalase-like, two-electron disproportionation of the substrate in acetonitrile.
Department of Physical Chemistry, Plovdiv University, 24 Tsar Assen St, 4000 Plovdiv, Bulgaria. ninadd@argon.acad.bg
Nina
N
Dimcheva
Elena
E
Horozova
D001555:Benzene Derivatives / Q000032:analysis*; D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D004800:Enzymes, Immobilized / Q000737:chemistry*; D005465:Fluorocarbon Polymers / Q000737:chemistry; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis*; D013696:Temperature
D001555:Benzene Derivatives; D004800:Enzymes, Immobilized; D005465:Fluorocarbon Polymers; C040402:perfluorosulfonic acid; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; C007164:cumene hydroperoxide