Biosensor potentiometric acetylcholine

R.E. Gyurcsanyi, Z. Vagfoldi, K. Toth, and G. Nagy Fast response potentiometric acetylcholine biosensor. Electroanalysis 11, 712-718 (1999). 

Potentiometric sensors — Potentiometric biosensors are miniaturized by reducing the dimensions of the transducer on which the enzyme is deposited. Once the transducer is miniaturized, the enzyme is immobilized by immersing the transducer in a solution of the enzyme and a cross-linking agent, glutaraldehyde, as described above. An acetylcholinesterase electrode was constructed in this way for the determination of acetylcholine [25] using a glass microelectrode... 

Potentiometric devices have a relatively high sensitivity and selectivity and abroad response range. They are also simple, rehable, and inexpensive and use commonly available instrumentation. Potentiometric enzyme-based biosensor systems have been recently reviewed. The most general approach for the determination of OP compounds (OPCs) is based on their inhibition of the activity of choline esterase enzymes. The presence of low concentrations of inhibitors strongly and specifically affects the enzyme activity. Therefore, by measuring the enzyme activity, the concentration of the OPCs can be assayed. Different enzymes, such as acetylcholine (ACh), BuCh, and, most often, pH sensors, were used as transducers in potentiometric biosensors. 

Potentiometric biosensors for OPCs have been designed based on the measurement of pH change. Most of them are based on the determination of the H" liberated during the hydrolysis of acetylcholine by using different H" -sensitive electrodes. 

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