Kinetic assays involving inhibition of specific enzymatic systems have been extensively applied as analytical methods for the detection of food and environmental contaminants, primarily among them pesticides, herbicides and heavy metals.

A particular form of enzymatic inhibition assays is represented by enzymatic inhibition bioelectrodes, whose flexibility can ensure the analysis of huge population of samples at very reduced costs.

An "ideal" inhibition biosensor should, in principle, ensure the rapid detection of all contaminants endowed with the same biological effect, without the need for an extensive sample pretreatment.

In this work data are reported on the possibility to detect environmental contaminants endowed with toxic effects, and especially organophosphates and organochlorides compounds, widely used as pesticides. A new biosensor is proposed for the direct determination of 2,4 dichloro phenoxyacetic acid (2,4D), i.e. one of the most powerful and diffused defoliant, also endowed with estrogenic properties. The proposed biosensor could be very useful for its potential application on line or "on the spot".