NASICON-based solid-electrolyte cell as transducer for enzyme sensors

Enzyme sensors for glucose and uric acid have been developed based on a solid-electrolyte cell using NASICON (Na3Zr2Si2PO12). These potentiometric devices respond reversibly to glucose and uric acid over a concentration range of two orders of magnitude with sensitivities of - 54 and - 52 mV/decade, respectively. The sensors can be used for a batch-type as well as a flow-through-type measuring system. Primarily the sensors respond to the H2O2 that is produced by the enzymatic reactions. The role of the three-phase region, electrolyte solution, sensing electrode metal and NASICON has been investigated. The liquid electrolyte/sensing electrode metal interface is found to work as a potential-determining as well as a rate-determining interface for the enzyme sensor.