The carbon paste electrode encrusted with a microreactor as glucose biosensor

The amperometric biosensors based on carbon paste electrodes (CPEs) encrust ed with single microreactor (MR) have been constructed for the determinatio n of glucose. The MRs were prepared from CPC-silica carrier (CPC) and were loaded with glucose oxidase (GO), mediator (M) and acceptor (A). As the med iator cation radical of 5,10-dimethyl-5,10-dihydrophenazine (DMDHP), N-meth ylphenazonium methyl sulfate (PMS) and o-benzoquinone (BQ) and as the accep tor Fe[EDTA]- or Fe(CN)(6)(3-) was used.. The biosensors acted at electrode potential 0.15-0.27 V versus Ag-AgCl electrode. The calibration graphs of the biosensors were linear in the range from 1.5 to 50 mM of glucose. The s ensitivity of the biosensors did not change at pH 6-8. The dissolved oxygen little (7%) influenced the biosensors response and 1 mM of ascorbic acid p roduced the response that was of equal value to 0.5 mM of glucose. The bios ensors showed high stability; no change of the response of the biosensors p repared by using the novel microreactor was observed at least for 6 months by keeping the loaded CPC at room temperature in silica container. An optim ization of the biosensors response against the GO, the mediator and the pol ymer amount was performed. The digital modeling of the biosensors action is following. (C) 1999 Elsevier Science S.A. All rights reserved.