Choline acetylcholine esterase electrode

Multienzyme systems have been used in carbon paste electrodes, providing bio-catalytic cascades that result in an analytical amperometric signal. For example, acetylcholine esterase (AChE) and choline oxidase (ChOx) have been co-immobilized in carbon pastes, either with monomeric TTF [145] or flexible ferrocene-containing polymers [146] as electron mediators. The primary reaction includes the hydrolysis of acetylcholine biocatalyzed by AChE, then the choline produced is oxidized by the electrically contacted ChOx giving an analytical amperometric signal corresponding to the acetylcholine concentration. 

Yao (1983) has shown that determination of acetylcholine esterase (AChE) activity is feasible with the above mentioned CME. ACh was hydrolyzed in a reaction vessel arranged in an FIA manifold upstream of the choline electrode. With a sample throughput of 40/h the sensor responded linearly to the enzyme activity over the range of 0.25 to 100 mU. 

Acetylcholine esterase [EC 3.1.1.7] Acetylcholine -1- HjO - Acetic acid + choline Acetylcholine H + Potentiometric electrode, FET... 

Choline electrodes coupled with acetylcholine esterase have been described as sensor for several acetylcholine esterase inhibitors NaF, butoxycarboxime, trichlorfon, dimethoate (25), malathion(2i) paraoxon, aldicarb (2i, 22). All these studies used model toxic compounds and consisted of preliminary laboratory investigations aimed at environmental pesticide control. 

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