Analytical Sciences
Online ISSN : 1348-2246
Print ISSN : 0910-6340
ISSN-L : 0910-6340
Original Papers
Ultrasensitive Biosensor for Detection of Organophosphorus Pesticides Based on a Macrocycle Complex/Carbon Nanotubes Composite and 1-Methyl-3-octylimidazolium Tetrafluoroborate as Binder Compound
Neuma das Mercês PEREIRAFernando Mota de OLIVEIRANara Rúbia PEREIRARodrigo Moreira VERLYDênio Emanuel Pires SOUTOLauro Tatsuo KUBOTAAuro Atsushi TANAKAFlavio Santos DAMOSRita de Cássia Silva LUZ
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2015 Volume 31 Issue 1 Pages 29-35

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Abstract

This work describes the highly sensitive detection of organophosphorus pesticides employing the cobalt(II) 4,4,4,4-tetrasulfo-phthalocyanine (CoTSPc) macrocycle complex, carbon nanotubes (CNT), and 1-methyl-3-octylimidazolium tetrafluoroborate (OMIM[BF4]). The technique is based on enzyme acetylcholinesterase (AChE) inhibition. The composite was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and amperometry. The AChE was immobilized on the composite electrode surface by cross-linking with glutaraldehyde and chitosan. The synergistic action of the CoTSPc/CNT/OMIM[BF4] composite showed excellent electrocatalytic activity, with a low applied potential for the amperometric detection of thiocholine (TCh) at 0.0 V vs. Ag/AgCl. The calculated catalytic rate constant, kcat, was 3.67 × 103 mol−1 L s−1. Under the optimum conditions, the inhibition rates of these pesticides were proportional to their concentrations in the ranges of 1.0 pmol L−1 to 1.0 nmol L−1 (fenitrothion), 2.0 pmol L−1 to 8.0 nmol L−1 (dichlorvos), and 16 pmol L−1 to 5.0 nmol L−1 (malathion).

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© 2015 by The Japan Society for Analytical Chemistry
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