抄録
Highly sensitive nitrate-selective field-effect transistors (nitrate ISFETs) were prepared by casting the FET gate insulator surface with 5 kinds of phosphate-ester based plasticizers, a nitrate-sensing material based on trihexadecyl-methylammonium nitrate and PVC matrix. The nitrate ISFETs with trioctylphosphate showed a linear response from 10-4.53mol dm-3 to 1mol dm-3. Using the most suitable nitrate-sensing membrane, we have prepared a prototype nitrate-checker composed of a nitrate ISFET and silver/silver chloride reference electrode and have demonstrated its preliminary application to real samples of rain water. We could obtain relatively good agreement of the values of nitrate concentration observed by the nitrate checker and conventional ion-chromatography and fairly good correlation coefficient between the both methods with 0.97.
