CHOLINESTERASE SENSOR BASED ON ELECTRODE MODIFIED WITH SILVER NANOPARTICLES

A cholinesterase sensor has been developed on the basis of a glassy carbon electrode modified with carbon black and silver nanoparticles and applied for the determination of enzyme substrate and inhibitor. Silver nanoparticles were synthesized by chemical reduction of silver nitrate with macrocyclic ligand containing catechol fragments. The working conditions for the measurement of the signal toward acetylthiocholine and malaoxon were established. Introduction of the silver nanoparticles made it possible to decrease the potential down to 150 mV and improve the sensitivity of the response toward malaoxon in comparison with the analogous biosensors without any modification of the transducer. The developed biosensor makes it possible to determine 2.10(-5) - 2.10(-4) M acetylthiohcoline and 4.10(-10) 4.10(-8) M malaoxon (detection limit is 0.4 nM).