Direct determination of etofenprox using surface plasmon resonance

Direct determination of etofenprox was performed using surface plasmon resonance. A thin gold film sputtered on to a glass surface was coated with plasma polymerized ethylene diamine (1,2-diaminoethane). Polyclonal anti-etofenprox antibody was covalently immobilized on this polymer. The response of the sensor was proportional to the etofenprox concentration over the 0.5–50 mg l−1 range; atrazine produced a negligible response under the same conditions. When commercially available sensor chips were used, the response did not show any dependence on the etofenprox concentration. This is believed to be due to the larger number of amino groups on the polymer surface of plasma polymerized ethylene diamine, allowing more antibody to be immobilized than on the commercially available sensor chips.