Cholinesterase Sensors Based on Thick-Film Graphite Electrodes for the Flow-Injection Determination of Organophosphorus Pesticides

Flow cholinesterase sensors based on planar thick-film graphite electrodes and immobilized preparations of acetyl- and butyrylcholinesterase with various activities were developed. Analytical parameters of the determination of organophosphorus pesticides depend on hydrophilic–hydrophobic interactions at the membrane–solution interface. When passing from the steady-state to flow-injection conditions of signal measurements, the limits of detection of coumaphos and chlorpyrifos-methyl decrease by a factor of 5–8, while the limit of detection of hydrophilic trichlorfon increases by a factor of 3–4. The cholinesterase sensors developed in his work can measure the concentrations of pesticides in a continuous mode for 8–12 h with the throughput of up to 5–6 measurements per hour.