Development of ionselective optode based on fast responding urea sensor and its application in flow injection analysis

A planar urea sensitive optical sensor was developed by using ammonium ion selective membrane as transducer and attenuated total internal reflection ( ATIR) as detection principle. The sensor consists of an immobilized urease enzyme containing reaction layer and of a plasticized PVC membrane containi ng nonactin as ionselective ionophore and ETH 5294 as chromoionophore. The paper described the investigations of the developed biosensor in flow throu gh system. A 30 sample/h rate was achieved for urea containing samples in t he 10(-5)-10(-3) M concentration range by using the fast-responding biosens or.