POTENTIOMETRIC BIOSENSOR IN DOUBLE MATRIX MEMBRANE TECHNOLOGY

A throw-away urea sensor is described. A pH-sensitive disposable sensor constructed using double matrix membrane technology was used as a transducer. Double matrix membrane technology describes a process where an ion-sensitive polymer matrix membrane is formed in the presence of an additional inert matrix for to improve the reproducibility of sensor production. In this case one-side silver-coated filter paper was used as the inert matrix which was encapsulated by a heat sealing film. A pH-sensitive membrane was casted into this filter paper and on the surface of this membrane a urease containing layer was deposited. The sensor responded to between 10(-2) mol/l and 10(-4) mol/l urea, the response slope was 32.7 mV/decade. The concentration range in which the sensor responds is important for clinical analysis. The main advantages of this pH-based urea electrode include miniature size as well as simple and low cost fabrication in a batch process.