Development of biosensors based on an electrolyte isolator semiconductor (EIS)-capacitor structure and their application for process monitoring

Simple non-structured fluoride sensitive electrolyte isolator semiconductor (EIS) chips consisting of Si/SiO2/Si2N4/LaF3 layers were used as transducers for measuring the H2O2, concentration by peroxidase (POD) and combined this H2O2 sensor with various oxidases, which form H2O2 in stoichiometric amount. The concentrations of the following analytes were measured with this system: glucose with glucose oxidase (GOD) and POD, maltose with amyloglucosidase (AGLU), mutarotase (MUT), GOD and POD, amylose with beta-amylase (Amyl), AGLU, MUT, GOD and POD, sucrose with invertase (INV), MUT, GOD and POD, ethanol with alcohol oxidase and POD, sulfite with sulfiteoxidase (SOD) and POD, xanthine with xanthineoxidase (XAD) and POD, phosphate with nucleoside-phosphorylase (NP), XOD and POD. The required enzymes were coimmobilized on the surface of the transducer (pF-EIS-CAP), mounted into a now cell, equipped with a reference electrode, integrated into a now injection analyser (FIA) system and operated with the CAFCA (Computer Assisted Flow Control and Analysis) automation programme.