Sol–gel immobilized biosensor for the detection of organophosphorous pesticides: A voltammetric method

Organophosphorous compounds are important neuroactive molecules whose presence exhibits significant analytical challenges. An acetylcholinesterase (AChE) based amperometric biosensor was developed by silica sol–gel film immobilization of the enzyme onto the carbon paste electrode. The mono enzyme bi...

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Bibliographic Details
Published in:Bioelectrochemistry (Amsterdam, Netherlands) Netherlands), 2012-02, Vol.83, p.19-24
Main Authors: Raghu, P., Kumara Swamy, B.E., Madhusudana Reddy, T., Chandrashekar, B.N., Reddaiah, K.
Format: Article
Language:English
Subjects:
Acetylcholinesterase
Acetylcholinesterase - chemistry
Acetylcholinesterase - metabolism
Acetylthiocholine - metabolism
Acetylthiocholine chloride
Animals
Biosensing Techniques - methods
Carbon paste electrode
Electrochemistry - methods
Electrodes
Electrophorus
Enzymes, Immobilized - chemistry
Enzymes, Immobilized - metabolism
Graphite - chemistry
Hydrogen-Ion Concentration
Immobilization
Limit of Detection
Methyl Parathion - analysis
Methyl parathion and acephate
Ointments - chemistry
Organothiophosphorus Compounds - analysis
Oxidation-Reduction
Pesticides - analysis
Phase Transition
Phosphoramides
Potentiometry - methods
Silica Gel - chemistry
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Summary:Organophosphorous compounds are important neuroactive molecules whose presence exhibits significant analytical challenges. An acetylcholinesterase (AChE) based amperometric biosensor was developed by silica sol–gel film immobilization of the enzyme onto the carbon paste electrode. The mono enzyme biosensor was used for the determination of two organophosphorous compounds such as methyl parathion (MP) and acephate in 0.1 M phosphate buffer (pH 7.0). The substrate used was acetylthiocholine chloride (ASChCl) confirmed the formation of thiocholine and it was electrochemically oxidized giving significant increase in anodic peak current around at 0.60 V versus calomel electrode. The influence of pH, enzyme loading and substrate concentration on the response of the biosensor was investigated. The monoenzyme biosensor provided linearity to methyl parathion and acephate in the concentration range of 0.1–0.5 ppb and 50–750 ppb with an incubation time of 20 min and 4 min. The detection limits under the optimum working conditions were found to be 0.08 ppb for methyl parathion and 87 ppb for acephate. The sensor shows good operational stability 89% of its original activity for 60 successive measurements. ► This paper describes the determination of organophosphorous pesticides. ► Biosensor, prepared through sol–gel immobilization method for the AChE entrapment. ► LOD of the biosensor was related to the capacity of the pesticide to inhibit AChE. ► Fast response, good reproducibility and sensitive enough to determine pesticides.
ISSN:1567-5394
1878-562X
DOI:10.1016/j.bioelechem.2011.08.002