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  • Küçük Resim
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    Ensuring traceability of organophosphate pesticides (OPs) through enzyme immobilized spheres
    (Springer, 2021) Hasanoglu ozkan, Elvan; Kurnaz Yetim, Nurdan; Nartop, Dilek; Sari, Nursen
    Currently, pesticide residues increasingly lead to health problems. Acetylcholinesterase enzyme (AChE) plays a role in detoxification processes due to their ability to scavenge organophosphates. Thus, this enzyme has been selected for the detection of pesticides. Herein, this study describes the preparation and application of appropriate new immobilized spheres that could be used for the detection of organophosphorus pesticide residues. That is a simple colorimetric enzymatic assay for the practical discovery of N-(Mercaptomethyl) phthalimide S-(O, O-dimethylphosphorodithioate) from organophosphorus pesticides (OPs) widely used in the treatment of sugar beet, apple, nut, corn, and tobacco. The process is based on the immobilization of acetylcholinesterase onto tryptophan FMPS-Trp, (FMPS-Trp)Pd(II), and (FMPS-Trp)Pt(II) functionalized spheres. Spectroscopic and microscopic techniques were used in the characterization of the spheres where scanning electron microscopy (SEM) is an essential tool. The (FMPS-Trp)Pt(II)-AChE showed a good affinity to acetylthiocholine chloride (ATCl) and was found to have the ability to catalyze the hydrolysis of ATCl with an apparent Michaelis-Menten constant value of 288 mM. The developed colorimetric process showed good qualitative analytical performance for Phosmet (OPs) detection as low as 10(-7) M. [GRAPHICS] .
  • Küçük Resim
    Öğe
    Enzyme immobilization on polymeric microspheres containing Schiff base for detection of organophosphate and carbamate insecticides
    (Elsevier, 2020) Nartop, Dilek; Yetim, Nurdan Kurnaz; Ozkan, Elvan Hasanoglu; Sari, Nursen
    In this study, polymeric microsphere including Schiff base TrisPS-pyr and TrisPS-pyr-Pt(II) were obtained by condensation reaction for improve the enzymatic properties of acetylcholinesterase (AChE) and detect harmful insects. Structures of the synthesized compounds were characterized by spectroscopic methods such as FT-IR, UV-Vis, SEM-EDX, GPC. Acetylcholinesterase enzyme was immobilized to these new polymeric microspheres and their properties such as activity, reusability and storage stability were investigated. In addition, the qualitative determination of carbamate [2,3-dihydro-2,2-dimethyl-7-benzofuranol N-methylcarbamate (carbofuran), 4-methylthio-3,5-xylyl methylcarbamate (methiocarb) and S-methyl-N- (methylcarbamoyl oxy) thioacetamide (methomyl)] and organophosphate [diethyl (dimethyl thiophosphoryl) succinate (malathion), O, S-dimethyl phosphoramidothioate acetyl (acephate) and chlorpyrifos methyl] insecticides by the immobilized enzyme was performed. The reason for the selection of these pesticides is because they are widely used to combat pests of agricultural products (hazelnut, corn, sugar beet, apple and tobacco) which are grown in our region. (C) 2019 Elsevier B.V. All rights reserved.
  • Küçük Resim
    Öğe
    Qualitative enzymatic detection of organophosphate and carbamate insecticides
    (Taylor & Francis Inc, 2020) Nartop, Dilek; Hasanoglu Ozkan, Elvan; Yetim, Nurdan Kurnaz; Sari, Nursen
    In this study, new polymers containing amides (TrisPS-Ntaa, andTrisPS-Ntaa-Fc) were synthesized by condensation reaction for qualitative identification of insecticides. The synthesized polymers, including amides were investigated by infrared spectroscopy (IR), scanning electron microscopy-energy dispersion X- ray spectrometry (SEM-EDX), and gel permeation chromatography (GPC). Then, acetylcholinesterase enzyme (AChE) was covalently immobilized on these polymers to improve properties (including activity, reusability, and storage stability). Accordingly, organophosphate (malathion, acephate, chlorpyrifos methyl) and carbamate (carbofuran, methiocarb, methomyl), which are used to prevent harmful organisms in some agricultural products were enzymatically determined based on their inhibitory activity on AChE.