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AMPEROMETRIC THICK-FILM STRIP ELECTRODES FOR MONITORING ORGANOPHOSPHATE NERVE AGENTS BASED ON IMMOBILIZED ORGANOPHOSPHORUS HYDROLASE. (R823663)
Citation:
Mulchandani, A., P. Mulchandani, W. Chen, J. Wang, AND L. Chen. AMPEROMETRIC THICK-FILM STRIP ELECTRODES FOR MONITORING ORGANOPHOSPHATE NERVE AGENTS BASED ON IMMOBILIZED ORGANOPHOSPHORUS HYDROLASE. (R823663). Analytical Chemistry. American Chemical Society, Washington, DC, 71:2246-2249, (1999).
Description:
An amperometric biosensor based on the immobilization of organophosphorus hydrolase
(OPH) onto screen-printed carbon electrodes is shown useful for the rapid, sensitive, and low-cost
detection of organophosphate (OP) nerve agents. The sensor relies upon the sensitive and rapid
anodic detection of the enzymatically generated p-nitrophenol product at the OPH/Nafion layer
immobilized onto the thick-film electrode in the presence of the OP substrate. The amperometric
signals are linearly proportional to the concentration of the hydrolyzed paraoxon and methyl parathion
substrates up to 40 and 5 mu M, showing detection limits of 9 x 10(-8) and 7 x 10-8 M,
respectively. Such detection limits are substantially lower compared to the (2-5) x 10(-6) M values
reported for OPH-based potentiometric and fiber-optic devices. The high sensitivity is coupled to a
faster and simplified operation, and the sensor manifests a selective response compared to analogous
enzyme inhibition biosensors. The applicability to river water sampling is illustrated. The attractive
performance and greatly simplified operation holds great promise for on-site monitoring of OP
pesticides. (12 References)