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Bi‐enzyme Electrochemical Sensor for Selective Determination of Organophosphorus Pesticides with Phenolic Leaving Groups
Author(s) -
Stoytcheva Margarita,
Zlatev Roumen,
Montero Gisela,
Velkova Zdravka,
Gochev Velizar
Publication year - 2017
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.201700380
Subject(s) - chemistry , amperometry , horseradish peroxidase , electrochemistry , selectivity , biosensor , electrochemical gas sensor , immobilized enzyme , detection limit , peroxidase , electrode , combinatorial chemistry , nuclear chemistry , inorganic chemistry , organic chemistry , chromatography , catalysis , enzyme , biochemistry
An amperometric bi‐enzyme sensor for detection of organophosphorus pesticides (OPs) with phenolic leaving groups, which are not electroactive, is presented in this work. The biosensing platform was created by a simple, controllable, and reproducible one‐step electrodeposition onto the surface of a glassy carbon electrode of a chitosan bionanocomposite with entrapped carboxylated multi walled carbon nanotubes, organophosphorus hydrolase (OPH), and horseradish peroxidase (HRP). The OPs determination involved a sequence of OPH and HRP‐catalyzed reactions resulting in phenolic radicals production, which were quantified by registering the current of their reduction at a potential of −50 mV vs. Ag, AgCl/KCl sat. The developed sensor was applied for the determination of prothiofos, as an example. At optimized conditions (pH 7.25 and H 2 O 2 concentration 200 μmol L −1 ), a LOD as low as 0.8 μmol L −1 was attained, while the linear concentration range was extended from 2.64 μmol L −1 up to 35 μmol L −1 . The main advantage of the proposed bi‐enzyme sensor is its selectivity toward the OPs with phenolic leaving groups, excluding the interference of the nitrophenyl‐substituted OPs.