Combining fluoroimmunoassay principles and fiber-optic fluorimetry has extended the available transduction schemes for development of fiber-optic sensors. Three representative designs are discussed focusing on a sensor configuration utilizing a controlled-release polymer to sustain a release of indicating reagents over long periods. This novel approach has been adapted for pesticide monitoring. A model system has been designed that releases the reagents of a homogeneous fluoroimmunoassay from an ethylene vinyl acetate polymer for the detection of atrazine. The sensor utilizes a competition reaction between fluorescent-labeled and unlabeled atrazine for the available binding sites on labeled anti-atrazine antibodies.
Fiber-optic sensors based on a controlled-release polymer provide sustained release of
indicating reagents over long periods. This technique allows irreversible chemistries to be
used in the design of sensors for continuous measurements. The first reported sensor used
8-hydroxypyrene- 1 ,3,6-trisulfonic acid and sulforhodamine 640 to measure pH
continuously for three months in the range of 5.5 to 8.0 with a precision units. The
sensor reported in this paper is based on a fluorescence energy transfer immunoassay. The
sensor was cycled through different concentrations of antigen continuously for 30 hours.
Although the sensor was not optimized, the data indicates the viability of the technique.