Abstract

Singlet Oxygen-based Electrosensing

Karolien De Wael, Professor, University of Antwerp

It is well known that phenolic compounds and, particularly, hydroquinone can shuttle electrons between horse radish peroxidase (HRP) and an electrode, which allows the bioelectrocatalytical reduction of H₂O₂ by the enzyme. When a phenolic compound shuttles the electrons, it passes through many cycles of oxidation and electrochemical reduction (regeneration) near the electrode. Such mechanism enhances the electrochemical response of the compound and has been employed for the electrochemical detection of phenols and their derivatives. However, H₂O₂ as an oxidant must be introduced into the system, which is an obvious limitation of the method. Our solution is to replace the enzyme with a photosensitizer which produces reactive oxygen species and can catalyze the oxidation of a compound of interest by O₂ that is naturally present in the measuring conditions. Here we used a fluorinated phthalocyanine complex of Zn which is capable to form singlet oxygen under red light illumination (? ca. 650 nm).