title: Ultrasensitive biosensor for detection of organophosphorus pesticides based on a macrocycle complex/carbon nanotubes composite and 1-methyl-3-octylimidazolium tetrafluoroborate as binder compound.
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, k(cat), was 3.67 × 10(3) 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).
authors: Departamento de Química, UFVJM.
authors: Neuma das Mercês
authors: Nd
authors: Pereira
authors: Fernando Mota
authors: FM
authors: de Oliveira
authors: Nara Rúbia
authors: NR
authors: Pereira
authors: Rodrigo Moreira
authors: RM
authors: Verly
authors: Dênio Emanuel Pires
authors: DE
authors: Souto
authors: Lauro Tatsuo
authors: LT
authors: Kubota
authors: Auro Atsushi
authors: AA
authors: Tanaka
authors: Flavio Santos
authors: FS
authors: Damos
authors: Rita de Cássia Silva
authors: Rde C
authors: Luz
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D007093:Imidazoles / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*; D010575:Pesticides / Q000032:analysis* / Q000737:chemistry
chemical_list: C534649:1-methyl-3-octylimidazolium bromide; D004800:Enzymes, Immobilized; D007093:Imidazoles; D007211:Indoles; D037742:Nanotubes, Carbon; D009942:Organometallic Compounds; D009943:Organophosphorus Compounds; D010575:Pesticides; C052738:cobalt tetrasulfophthalocyanine; D000110:Acetylcholinesterase