CONTINUOUS-FLOW IMMUNOSENSOR FOR ATRAZINE DETECTION

The hapten atrazine was detected under continuous flow conditions usin g a micro-column which contained immobilized monoclonal antibodies (Ab ) against atrazine and atrazine labeled with alkaline phosphatase (An ). The equilibrium of the antibody-hapten system, was achieved by a co ntinuous flow of the tracer An through the micro-column containing th e immobilized antibodies. The activity of the tracer was monitored con tinuously, after the micro-column, by an amperometric detector using p -hydroquinone phosphate as substrate. When pulses of unlabeled atrazin e (An) were added to the An flowing continuously through the micro-co lumn, An bound to the antibody was displaced, with a consequent chang e of the detector signal. By this method atrazine concentrations in th e range 9-180 mu g/l were monitored under conditions of continuous ope ration. Since the equilibrium condition for the system Ab-An was cont inuously restored by the flow of An through the micro-column the rege neration of the antibody was not required. (C) 1997 Elsevier Science L imited.