Organophosphorus Pesticide Analysis Using Solid State Sensors

Two new solid-state biosensors are compared in the analysis of organophosphorus pesticides. The method is based on the inhibiting action of these compounds versus the enzyme butyrylcholinesterase. The first sensor was made up of a graphite electrode coated with an ion-selective polymeric membrane containing tridodecylamine and sensitive to pH, coupled to the enzyme butyrylcholinesterase immobilised on a functionalised nylon membrane superimposed on the solid-state ISE. The second sensor was obtained by immobilising the same enzyme using polyazetidine on the "gate" of a FET rendered sensitive to pH by means of a polymeric membrane containing the same exchanger. The response of the two biosensors to the substrate, i.e. butyrylcholine (BuCh),and the inhibition of Paraoxon, one of the most common organophosphorus pesticides, were tested.