Disposable glucose sensor plate and disposable multi-ion sensor plate

Abstract

A disposable glucose sensor plate and a disposable multi-ion sensor plate sensitive to sodium, potassium, chloride and hydrogen ions have been developed for clinical use. For a disposable-type sensor, simplicity of operation, especially the elimination of calibration, is necessary in addition to measurement accuracy and precision. To obtain a stable potential, a simple reference electrode was fabricated on a plate together with the ion-sensitive electrode using electrolyte gel cake on a Ag/AgCl electrode. The ion sensors had a sensitivity of 55–58 mV/dec and showed a linear response relative to the logarithm of each ion activity. The response to a given solution was reproducible to within approximately ±1.0 mV, corresponding to a final error of ±4% without any electrode calibration. The glucose sensor plate was prepared by immobilization of GOD over the pH electrode of the sensor plate. Responses to a given glucose solution ranging from 10 to 250 mg/dl were obtained and were reproducible to within approximately 8% in a normal glucose range without calibration before use. These results suggest that further improvement is necessary in order to obtain uniform electrode electrochemical characteristics, so that clinical application without pre-use calibration can be achieved.