Rotating bioreactor based on an electron transfer mediated by osmium complexes incorporating a continuous-flow/stopped-flow system - Application to the determination of glucose in serum samples

A recently introduced redox osmium complex of the type [Os(bpy)(2)CI(pyX](), where pyX corresponds to a pyridine derivative bearing an aldehyde group , and glucose oxidase [EC 1.1.3.4] were covalently immobilized on the glass y carbon electrode surface (upper cell body). This approach has been design ed in a sealed cell to be used under continuous-flow/stopped-flow/continuou s-flow processing. The operating characteristic of the integrated bioreacto r/detector unit has been utilized in the determination of glucose in serum samples using the electroactive polymer as mediator in the re-oxidation of GOx and amperometric monitoring. The determinations are based on the rate o f response tinder stopped-flow conditions. The trend in values of the appar ent Michaelis-Menten constant confirms the validity of the approach to sens itive determination utilizing very small amounts of biocatalysts. The deter mination of glucose was possible with a limit of detection of 0.020 mM in t he processing of as many as 30 samples per hour. (C) 2001 Elsevier Science B.V. All rights reserved.