Detection of Multiple Herbicide Residues Using A Planar Array Evanescent Field Immunosensor

A planar array evanescent immunosensor, equipped with a charge-coupled device (CCD) as a detector was used to simultaneously detect pesticides, paraoxon, carbofuran and tetrachloroethylene. Wells approximately 2.5 mm in diameter were formed on glass slides using a photoactivated optical adhesive. Coating haptens were covalently attached to the bottoms of the circular wells to form a sensing surface. The detection of the hapten was completed through competitive immune-reaction between the coating haptens, and haptens in solution, with the corresponding antibody in solution. The identification and amount of antibody bound at each location on the slide were determined by quantitative image analysis. Concentrations as low as 0.5 ng/mL of paraoxon, 0.1 ng/mL of carbofuran, and 0.2 ng/mL of tetrachloroethylene could be measured.