Disposable interference-free glucose biosensor based on an electropolymerised poly(pyrrole) permselective film

Miniaturised disposable amperometric biosensors for glucose determination i n serum are described. A commercially available three-electrode system crea ted on a planar corundum ceramic base was used as biosensor substrate and t he working Pt electrode was modified by an electrogenerated overoxidised po ly(pyrrole) film (PPYox). After the optimisation of the PPy layer synthesis, two different approaches were investigated for glucose oxidase (GOD) immobilisation: enzyme entrapm ent into the electropolymerised film by an 'all-electrochemical' procedure (PPYox/GOD) and gel-entrapment over the PPYox modified electrode by co-cros slinking with glutaraldehyde/bovine serum albumin (PPYox/GOD-gel). A comparison of the sensitivities to glucose, performed by dropping 50 mu l of the sample solutions onto the relevant electrode systems, showed that b oth sensors have a linearity range extending up to 10 mM, though Pt/PPYox/G OD-gel sensor is more sensitive (168+/-15 versus 53+/-7 nAm/M), The two sen sors showed remarkable anti-interferent selectivity, moreover the PPYox/GOD -gel sensor had also a good stability and could be used for flow injection analysis of glucose, with a linearity range extending up to 25 mM. (C) 2000 Elsevier Science B.V. All rights reserved.