CHOLINESTERASE BASED BIOREACTOR FOR DETERMINATION OF PESTICIDES

A novel analytical system for the in-flow quantitative determination o f acetylcholine (ACh) and acetylcholinesterase (AChE) inhibitors is pr esented. Reliable and reproducible values in the monitoring of ACh, of carbamic acid derivatives and of organophosphorous compounds have bee n obtained thanks to a device realized by coupling an AChE-based whole plant tissue column bioreactor with a traditional choline oxidase (Ch O) biosensor. AChE was extracted from the inner part of a grapefuit sh ell (Albedum pomi citreum), coupled to chitin by glutaraldehyde and im mobilized into a glass column bioreactor, whose outlet was connected t o a thermostated flow-through cell incorporating the ChO biosensor. A sharp improvement in the sensitivity limits was obtained by recycling the sample solution into the bioreactor. The efficacy of the analytica l system here presented was checked on standard solutions of ACh and o n three of the most commonly used inhibitors of AChE (aldicarb, malath ion and paraoxon), widely employed mainly as the active components of pesticides and insecticides.