ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Detection of hydrogen peroxide and glucose by enzyme product precipitation on sensor surface

Tomáš Juřík and Petr Skládal

Department of Biochemistry, Faculty of Science

E-mail: skladal@chemi.muni.cz

Abstract: Biocatalysed precipitation of an insoluble product accumulated on the enzyme-modified electrode surface was applied as the amplification path for low concentration sensing of hydrogen peroxide and glucose. Sensitive electrochemical and quartz-crystal microbalance (QCM) biosensors based on biocatalytic precipitation were developed. A horseradish peroxidase (HRP) monolayer-modified electrode was used to sense H₂O₂ via the oxidation of 4-chloro-1-naphthol (4CN) forming insoluble benzo-4-chlorocyclohexadienone. Additionally, the bienzyme system employed glucose oxidase (GOx) linked to HRP/4CN. The amount of the precipitate assembled on the sensing surface corresponded to the concentration of analytes and to the length of the incubation interval. The precipitated deposits were followed as a change of impedance using cyclic voltammetry (CV), mass change was determined continuously using a microgravimetric quartz-crystal microbalance, and optical microscopy enabled the visualisation of the precipitate. Regeneration of the enzyme-modified electrode was performed using cathodic reduction of the insoluble product. Thus, a simple biosensor for multiple analyses with low detection limits and of low cost can be developed.

Keywords: biocatalysed precipitation – horseradish peroxidase – hydrogen peroxide – 4-chloro-1- naphthol – cyclic voltammetry – quartz crystal microbalance

Full paper is available at www.springerlink.com.

DOI: 10.1515/chempap-2015-0003

Chemical Papers 69 (1) 167–175 (2015)