USE OF A FIBER OPTIC IMMUNOSENSOR FOR THE DETECTION OF PESTICIDES

The principle of a competitive immunoassay was employed for the development of an optical immunosensor for pesticide analysis. Triazines were assayed using fluorescence labelled antibodies. On one end of a hard clad silica fibre, which was stripped of cladding, a derivative of the s-triazines, aminohexylatrazine, was immobilized. The fibre was inserted in a flow through cuvette. Triazine antibodies conjugated with fluorescein isothiocyanate (FITC) were detected after binding to the fibre surface by the fluorescence coupled into the fibre via the evanescent field. In the presence of triazines the fluorescence signal decreases due to the inhibition of antibody binding to the fibre. The detection limit of the sensor for terbutryn was 0.1 ng/ml (obtained using a monoclonal antibody). This is the maximum concentration of a single pesticide which may be present in drinking water, according to European Community regulations.