title: Sol-gel immobilized biosensor for the detection of organophosphorous pesticides: a voltammetric method.
abstract: 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 0.1M 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.
authors: Department of Chemistry, S.V.U. College of Sciences, Sri Venkateswara University, Tirupati-517502, Andhra Pradesh, India.
authors: P
authors: P
authors: Raghu
authors: B E Kumara
authors: BE
authors: Swamy
authors: T Madhusudana
authors: TM
authors: Reddy
authors: B N
authors: BN
authors: Chandrashekar
authors: K
authors: K
authors: Reddaiah
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry / Q000378:metabolism*; D000122:Acetylthiocholine / Q000378:metabolism; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004593:Electrophorus; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D006108:Graphite / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D008743:Methyl Parathion / Q000032:analysis; D009824:Ointments / Q000737:chemistry; D009946:Organothiophosphorus Compounds / Q000032:analysis*; D010084:Oxidation-Reduction; D010575:Pesticides / Q000032:analysis*; D044367:Phase Transition; D063088:Phosphoramides; D011199:Potentiometry / Q000379:methods*; D058428:Silica Gel / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D009824:Ointments; D009946:Organothiophosphorus Compounds; D010575:Pesticides; D063088:Phosphoramides; C001969:acephate; D008743:Methyl Parathion; D000122:Acetylthiocholine; D058428:Silica Gel; D006108:Graphite; D000110:Acetylcholinesterase