Potentiometric detection of pesticides in water samples

An enzyme-based sensor for the determination of organophosphate pesticides is described. It is based on the potentiometric determination of the inhibiting properties of the pesticides on the acetylcholinesterase activity. The enzyme was deposited onto commercially available membranes placed on the surface of an ion sensitive field effect transistor. The usage of this kind of membranes improves the behaviour of the system with respect to the application of polymeric matrices chemically anchored to the surface of the sensor. The results presented here show a good sensitivity for the used pesticide (0.1 mg l−1) and the possibility of using the sensor for a preliminary screening of different pollutants on water samples simply by changing the sensitive membrane.