Organophosphorus Pesticide (Paraoxon) Analysis using Solid State Sensors

A comparison of two new solid-state biosensors for organophosphorus pesticide analysis is presented, both of which employ the inhibiting action of these toxic compounds versus the enzyme butyrylcholinesterase. The indicating sensor used was a graphite electrode, or a FET, coated with an ion-selective polymeric membrane sensitive to pH containing tridodecylamine as exchanger. The former was coupled to the enzyme butyrylcholinesterase immobilised on a functionalized nylon net, while the latter employed the same enzyme coated on the polymeric membrane by means of polyazetidine prepolymer. The responses of the two biosensors to the substrate, i.e. butyrylcholine (BuCh), and to the inhibitor, i.e. Paraoxon, one of the most common organophosphorus pesticides, were tested.