GLUCOSE-SENSITIVE CONDUCTOMETRIC BIOSENSOR WITH ADDITIONAL NAFION MEMBRANE - REDUCTION OF INFLUENCE OF BUFFER CAPACITY ON THE SENSOR RESPONSE AND EXTENSION OF ITS DYNAMIC-RANGE

Glucose-sensitive enzyme conductometric biosensors based on interdigit ated gold electrodes were prepared by cross-linking glucose oxidase wi th bovine serum albumin in a saturated glutaraldehyde vapour on the se nsor chips. Nafion membranes were deposited on top of the glucose sens or by a spin-coating procedure. The effects of buffer concentration an d ionic strength were examined for the glucose sensors with and withou t Nafion membranes. Additional Nafion membranes resulted in a substant ial reduction of the effect of buffer concentration on the sensor resp onse and in an extension of the dynamic range of the sensor up to a gl ucose concentration of more than 10 mM Moreover the comparison of the properties of the developed conductometric glucose biosensors (operati onal and storage stability, reproducibility of measurements) demonstra tes better performance of the sensor with an additional Nafion membran e.