Fast Response Potentiometric Acetylcholine Biosensor

A simple, convenient method is proposed for the preparation of fast response potentiometric acetylcholine (ACh) biosensors based on pH detection. As signal transducer antimony pH electrodes with flat, easily renewable surface were used. Among different immobilization techniques tested the immobilization of acetylcholinesterase (AChE) onto the antimony disk electrode surface by intermolecular cross linkage of AChE and BSA via glutaraldehyde vapor in vacuum proved to be the most advantageous with respect to the analytical parameters of the biosensor. The biosensor was tested for the determination of an organophosphorus type insecticide; trichlorfon using an indirect approach based on the AChE inhibiting character of this pesticide. After each inhibition measurement cycle the biosensor was reactivated in pyridin-2-aldoxime methiodide for prolonged lifetime. The fast response of the ACh biosensor resulted in a considerable decrease of the real analysis time of the inhibitor.