Impedance-Based Immobilized Enzyme Biosensor for Detection of Organophosphates

摘要

This paper describes the development of an electrochemical impedance-based biosensor for the detection of organophosphates. The biosensor consisted of a carbon paste electrode, modified with an immobilized organophosphate-sensitive enzyme layer. The enzyme was immobilized through crosslinking with glutaraldehyde, polyethyleneimine, and additional cell material. The sensor signal and response to paraoxon substrate was tested versus two different electrode arrangements and over several applied dc potentials. The sensor was capable of measuring 10 μM paraoxon in buffer solution. Stability of the sensor stored in air over time was investigated. Results are shown for the biosensor versus a paraoxon substrate operating in 50 mM HEPES buffer at 150 mV, 0 mV, and -150 mV vs. Ag/AgCl.