The carbon paste electrode encrusted with a microreactor as glucose biosensor

The amperometric biosensors based on carbon paste electrodes (CPEs) encrusted with single microreactor (MR) have been constructed for the determination 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 mediator cation radical of 5,10-dimethyl-5,10-dihydrophenazine (DMDHP), N-methylphenazonium methyl sulfate (PMS) and o-benzoquinone (BQ) and as the acceptor 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 sensitivity 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 produced the response that was of equal value to 0.5 mM of glucose. The biosensors showed high stability; no change of the response of the biosensors prepared by using the novel microreactor was observed at least for 6 months by keeping the loaded CPC at room temperature in silica container. An optimization of the biosensors response against the GO, the mediator and the polymer amount was performed. The digital modeling of the biosensors action is following. (C) 1999 Elsevier Science S.A. All rights reserved.