Flow Injection Amperometric Enzyme Biosensor for Direct Determination of Organophosphate Nerve Agents

A flow injection amperometric biosensor for the deter mination of organophosphate nerve agents was developed. The biosensor incorporated an immobilized enzyme reactor that contains the enzyme organophosphorus hydrolase covalently immobilized on activated aminopropyl controlled pore glass beads and a...

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Bibliographic Details
Published in:Environmental science & technology 2001-06, Vol.35 (12), p.2562-2565
Main Authors: Mulchandani, Priti, Chen, Wilfred, Mulchandani, Ashok
Format: Article
Language:English
Subjects:
Analysis methods
Applied sciences
Aryldialkylphosphatase
Biosensors
Chemical Warfare Agents - analysis
Electrochemistry
Electrodes
Environmental monitoring
Environmental Monitoring - instrumentation
Environmental Monitoring - methods
Enzymes
Esterases - metabolism
Exact sciences and technology
Groundwater
Natural water pollution
Nervous system
Organophosphorus Compounds - analysis
Pesticides
Poisons
Pollution
Public health
Sensitivity and Specificity
Water Pollutants, Chemical - analysis
Water Supply
Water treatment and pollution
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Summary:A flow injection amperometric biosensor for the deter mination of organophosphate nerve agents was developed. The biosensor incorporated an immobilized enzyme reactor that contains the enzyme organophosphorus hydrolase covalently immobilized on activated aminopropyl controlled pore glass beads and an electrochemical flow-through detector containing carbon paste working electrode, a silver/silver chloride reference electrode, and stainless steel counter electrode. The organophosphorus hydrolase catalyzed the hydrolysis of organophosphate with nitrophenyl substituent to generate p-nitrophenol which is then detected downstream electrochemically at the carbon paste electrode poised at 0.9 V vs the reference electrode. The amperometric response of the biosensor was linear up to 120 μM and 140 μM, with lower detection limits of 20 nM and 20 nM, for paraoxon and methyl parathion, respectively. The response was very reproducible (RSD 2%, n = 35) and stable for over 1 month when the immobilized enzyme column was stored at 4 °C. Each assay took ca. 2 min giving a sample throughput of 30 h-1. The applicability of the biosensor to monitor paraoxon and methyl parathion in distilled water and simulated well water was demonstrated.
ISSN:0013-936X
1520-5851
DOI:10.1021/es001773q