PLANAR WAVE-GUIDE ION-SELECTIVE SENSORS

A potassium ion-selective planar waveguide total internal reflection ( TIR) mode optical sensor was prepared for flow injection application b y casting thin film optode membranes onto a glass substrate. For this sensor, a potassium selective ionophore is incorporated in plasticized polyvinyl chloride film sensitized with a hydrogen selective ionophor e. The sensor response to potassium ion is determined by measuring the attenuation of a HeNe laser propagated in this thin film device. The laser was coupled into and out of the sensor using grating couplers pr oviding an inexpensive, environmentally stable sensor. The sensitivity of the waveguide based how injection device is approximately 0.05 mM K+, while the rate of analysis is about 180 samples per hour. (C) 1997 Elsevier Science B.V.