A redox hydrogel integrated PQQ–glucose dehydrogenase based glucose electrode
The present work describes the design and characteristics of a glucose electrode based on a newly isolated and purified, oxygen-independent, pyrrole quinoline quinone glucose dehydrogenase (PQQ–GDH) integrated in a redox hydrogel (poly(1-vinylimidazole) complexed with Os(4-4′-dimethylbipyridine)2Cl) using poly(ethylene glycol)diglycidyl ether (PEGDGE) as a crosslinker. The influence of the buffer’s nature and the presence of PQQ and Ca2+ ions on the enzyme stability were considered. The characteristics of the optimal electrode design were compared to those obtained for similarly prepared, glucose oxidase based electrodes. The optimal electrode configuration inserted in a single manifold flow injection system, was characterised by a linear range up to 100 µM, a sensitivity of 5.9 mA M–1 cm–2, and a detection limit of 5 µM (calculated as three times the signal-to-noise ratio).