The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Wolfgang Schwack - One of the best experts on this subject based on the ideXlab platform.
-
Photodegradation of Phosmet in wool wax models and on sheep wool: determination of wool wax bound Phosmet by means of isotope ratio mass spectrometry.
Journal of agricultural and food chemistry, 2005Co-Authors: Katrin Sinderhauf, Wolfgang SchwackAbstract:The photochemical reactions of Phosmet, an organophosphorus insecticide used for plant protection and for control of ectoparasites on productive livestock, were studied in the presence of wool wax. Induced by UV light, Phosmet features numerous degradation pathways as well as photoaddition reactions with lipid structure moieties. In model irradiation experiments of Phosmet in mixtures of solvents (cyclohexane, cyclohexene, 2-propanol) and fatty acid methyl esters (methyl stearate, methyl oleate, 12-hydroxymethyl stearate), both adjusted to the hydroxyl and iodine values of wool wax, half-lives were determined to be approximately 7 and 16 h, respectively. Irradiation of Phosmet on crude sheep wool resulted in a degradation rate of 65% after 24 h. In tracer studies with stable isotope labeled Phosmet ([15N]Phosmet) in commercial lanolin and on raw sheep wool, employing a sunlight simulator and natural sunlight, wool wax bound Phosmet was formed. After extraction and measurement by elemental analyzer/isotope...
-
Photodegradation chemistry of the insecticide Phosmet in lipid models and in the presence of wool wax, employing a 15N-labeled compound.
Journal of agricultural and food chemistry, 2004Co-Authors: Katrin Sinderhauf, Wolfgang SchwackAbstract:The organophosphorus insecticide Phosmet is commonly used for plant protection as well as against pests on animals. Phosmet features numerous degradation pathways induced by UV irradiation. In this study, we focused on the reaction possibilities of Phosmet in the presence of lipophilic substances with olefinic structure elements, as they are frequently found in animal fur lipids, especially in wool wax. In the first step, simple models were employed to characterize the structural types of formed photoaddition products. On irradiation in the presence of cyclohexene, three photoaddition products were identified, a (4π + 2π) cycloaddition product of Phosmet and cyclohexene and two diastereoisomer carbinols. Likewise, in more sophisticated models employing fatty acid methyl esters for irradiation experiments, Phosmet was readily photodegraded. In the presence of methyl oleate, also 1:1 photoaddition products could easily be identified by means of liquid chromatography−mass spectrometry, using a stable isotope...
-
Optimised synthesis of the 15N-labelled insecticide Phosmet (1)
Journal of Labelled Compounds and Radiopharmaceuticals, 2004Co-Authors: Katrin Sinderhauf, Wolfgang SchwackAbstract:A simple strategy for the small-scale synthesis of the 15N-labelled insecticide Phosmet has been developed, starting from 15N-phthalimide-K. Copyright © 2004 John Wiley & Sons, Ltd.
-
Photolysis experiments on Phosmet, an organophosphorus insecticide
Journal of agricultural and food chemistry, 2003Co-Authors: Katrin Sinderhauf, Wolfgang SchwackAbstract:The organophosphorus insecticide Phosmet is used in plant protection as well as against parasites on animals. Phosmet showed numerous photoinduced reaction pathways, which first were studied in the presence of model environments for animal fur lipids (e.g., wool wax). The model solvents for saturated and unsaturated lipids were cyclohexane and cyclohexene, whereas methanol and 2-propanol were used as models for primary and secondary alcohol moieties of lipids. The measured degradation rates over an irradiation period of 7 h in all solvents used were very similar (49-55%). The obtained photoproducts generally included phthalimide, N-hydroxymethylphthalimide, and N-methoxymethylphthalimide. Furthermore, depending on the solvent used, additional degradation products were detectable as N-isopropoxy- and N-methylphthalimide in the presence of 2-propanol and cyclohexene, respectively. However, in the presence of cyclohexene, despite the similar turnover, distinctly lower concentrations of photoproducts were found, indicating further still unknown degradation pathways. Irradiations in methanol with increasing percentages of water led to higher degradation rates; however, the products were found to be the same. Irradiation experiments with pure Phosmet on silica TLC plates and glass surfaces resulted in degradation rates of 19 and 32%, respectively, after 6 h. The results obtained clearly demonstrate for the first time that the photoinduced degradation of Phosmet is strongly dependent on the chemical environment, affecting less the turnover than the photoproducts formed. The results additionally demonstrate the need to investigate the degradation behavior of Phosmet on wool and in the presence of wool wax.
Katrin Sinderhauf - One of the best experts on this subject based on the ideXlab platform.
-
Photodegradation of Phosmet in wool wax models and on sheep wool: determination of wool wax bound Phosmet by means of isotope ratio mass spectrometry.
Journal of agricultural and food chemistry, 2005Co-Authors: Katrin Sinderhauf, Wolfgang SchwackAbstract:The photochemical reactions of Phosmet, an organophosphorus insecticide used for plant protection and for control of ectoparasites on productive livestock, were studied in the presence of wool wax. Induced by UV light, Phosmet features numerous degradation pathways as well as photoaddition reactions with lipid structure moieties. In model irradiation experiments of Phosmet in mixtures of solvents (cyclohexane, cyclohexene, 2-propanol) and fatty acid methyl esters (methyl stearate, methyl oleate, 12-hydroxymethyl stearate), both adjusted to the hydroxyl and iodine values of wool wax, half-lives were determined to be approximately 7 and 16 h, respectively. Irradiation of Phosmet on crude sheep wool resulted in a degradation rate of 65% after 24 h. In tracer studies with stable isotope labeled Phosmet ([15N]Phosmet) in commercial lanolin and on raw sheep wool, employing a sunlight simulator and natural sunlight, wool wax bound Phosmet was formed. After extraction and measurement by elemental analyzer/isotope...
-
Photodegradation chemistry of the insecticide Phosmet in lipid models and in the presence of wool wax, employing a 15N-labeled compound.
Journal of agricultural and food chemistry, 2004Co-Authors: Katrin Sinderhauf, Wolfgang SchwackAbstract:The organophosphorus insecticide Phosmet is commonly used for plant protection as well as against pests on animals. Phosmet features numerous degradation pathways induced by UV irradiation. In this study, we focused on the reaction possibilities of Phosmet in the presence of lipophilic substances with olefinic structure elements, as they are frequently found in animal fur lipids, especially in wool wax. In the first step, simple models were employed to characterize the structural types of formed photoaddition products. On irradiation in the presence of cyclohexene, three photoaddition products were identified, a (4π + 2π) cycloaddition product of Phosmet and cyclohexene and two diastereoisomer carbinols. Likewise, in more sophisticated models employing fatty acid methyl esters for irradiation experiments, Phosmet was readily photodegraded. In the presence of methyl oleate, also 1:1 photoaddition products could easily be identified by means of liquid chromatography−mass spectrometry, using a stable isotope...
-
Optimised synthesis of the 15N-labelled insecticide Phosmet (1)
Journal of Labelled Compounds and Radiopharmaceuticals, 2004Co-Authors: Katrin Sinderhauf, Wolfgang SchwackAbstract:A simple strategy for the small-scale synthesis of the 15N-labelled insecticide Phosmet has been developed, starting from 15N-phthalimide-K. Copyright © 2004 John Wiley & Sons, Ltd.
-
Photolysis experiments on Phosmet, an organophosphorus insecticide
Journal of agricultural and food chemistry, 2003Co-Authors: Katrin Sinderhauf, Wolfgang SchwackAbstract:The organophosphorus insecticide Phosmet is used in plant protection as well as against parasites on animals. Phosmet showed numerous photoinduced reaction pathways, which first were studied in the presence of model environments for animal fur lipids (e.g., wool wax). The model solvents for saturated and unsaturated lipids were cyclohexane and cyclohexene, whereas methanol and 2-propanol were used as models for primary and secondary alcohol moieties of lipids. The measured degradation rates over an irradiation period of 7 h in all solvents used were very similar (49-55%). The obtained photoproducts generally included phthalimide, N-hydroxymethylphthalimide, and N-methoxymethylphthalimide. Furthermore, depending on the solvent used, additional degradation products were detectable as N-isopropoxy- and N-methylphthalimide in the presence of 2-propanol and cyclohexene, respectively. However, in the presence of cyclohexene, despite the similar turnover, distinctly lower concentrations of photoproducts were found, indicating further still unknown degradation pathways. Irradiations in methanol with increasing percentages of water led to higher degradation rates; however, the products were found to be the same. Irradiation experiments with pure Phosmet on silica TLC plates and glass surfaces resulted in degradation rates of 19 and 32%, respectively, after 6 h. The results obtained clearly demonstrate for the first time that the photoinduced degradation of Phosmet is strongly dependent on the chemical environment, affecting less the turnover than the photoproducts formed. The results additionally demonstrate the need to investigate the degradation behavior of Phosmet on wool and in the presence of wool wax.
G. Istamboulie - One of the best experts on this subject based on the ideXlab platform.
-
Ultra-sensitive biosensor based on genetically engineered acetylcholinesterase immobilized in poly (vinyl alcohol)/Fe–Ni alloy nanocomposite for Phosmet detection in olive oil
Food Chemistry, 2016Co-Authors: A.y. El-moghazy, E.a. Soliman, H.z. Ibrahim, T. Noguer, J.-l. Marty, G. IstamboulieAbstract:An ultra-sensitive screen-printed biosensor was successfully developed for Phosmet detection in olive oil, based on a genetically-engineered acetylcholinesterase (AChE) immobilized in a azide-unit water-pendant polyvinyl alcohol (PVA-AWP)/Fe-Ni alloy nanocomposite. Fe-Ni not only allowed amplifying the response current but also lowering the applied potential from 80 mV to 30 mV vs Ag/AgCl. The biosensor showed a very good analytical performance for Phosmet detection, with a detection limit of 0.1 nM. This detection limit is lower than the allowable concentrations set by international regulations. In addition to the good reproducibility, operational and storage stability, the developed biosensor was successfully used for the determination of Phosmet in olive oil samples without any laborious pre-treatment. The Phosmet recovery rate was about 96% after a simple liquid-liquid extraction.
A.y. El-moghazy - One of the best experts on this subject based on the ideXlab platform.
-
Ultra-sensitive biosensor based on genetically engineered acetylcholinesterase immobilized in poly (vinyl alcohol)/Fe–Ni alloy nanocomposite for Phosmet detection in olive oil
Food Chemistry, 2016Co-Authors: A.y. El-moghazy, E.a. Soliman, H.z. Ibrahim, T. Noguer, J.-l. Marty, G. IstamboulieAbstract:An ultra-sensitive screen-printed biosensor was successfully developed for Phosmet detection in olive oil, based on a genetically-engineered acetylcholinesterase (AChE) immobilized in a azide-unit water-pendant polyvinyl alcohol (PVA-AWP)/Fe-Ni alloy nanocomposite. Fe-Ni not only allowed amplifying the response current but also lowering the applied potential from 80 mV to 30 mV vs Ag/AgCl. The biosensor showed a very good analytical performance for Phosmet detection, with a detection limit of 0.1 nM. This detection limit is lower than the allowable concentrations set by international regulations. In addition to the good reproducibility, operational and storage stability, the developed biosensor was successfully used for the determination of Phosmet in olive oil samples without any laborious pre-treatment. The Phosmet recovery rate was about 96% after a simple liquid-liquid extraction.
Akhtar Hayat - One of the best experts on this subject based on the ideXlab platform.
-
An insect acetylcholinesterase biosensor utilizing WO3/g-C3N4 nanocomposite modified pencil graphite electrode for Phosmet detection in stored grains.
Food chemistry, 2021Co-Authors: Sehrish Bilal, M. Mudassir Hassan, Muhammad Fayyaz Ur Rehman, Muhammad Nasir, Amtul Jamil Sami, Akhtar HayatAbstract:Abstract This study was undertaken to assess the potential of Tribolium castaneum (Red flour beetle) acetylcholinesterase (Tc-AChE) based electrochemical biosensor integrating WO3/g-C3N4 nanocomposite modified Pencil graphite electrode to detect an organophosphate insecticide, Phosmet. The WO3/g-C3N4 nanocomposite provides a non-toxic, biocompatible surface for binding the enzyme on the electrode surface, attributed to its large surface area, high conductivity, and low ohmic resistance. The proposed biosensor shows a very good analytical performance with LOD 3.6 nM for Phosmet and effectively determined Phosmet in wheat with a 99% recovery rate. Furthermore, molecular docking deciphers the binding interactions of Phosmet with Tc-AChE using a modified AutoDock LGA algorithm and an AMBER03 force field in YASARA. The kinetic parameters strongly suggest the high potency of inhibitor with the enzyme. This study presents an adaptable, rapid, and straightforward approach that opens ways towards real progress in developing commercial biosensors for pesticide detection.
-
an insect acetylcholinesterase biosensor utilizing wo3 g c3n4 nanocomposite modified pencil graphite electrode for Phosmet detection in stored grains
Food Chemistry, 2021Co-Authors: Sehrish Bilal, Muhammad Fayyaz Ur Rehman, Muhammad Nasir, Amtul Jamil Sami, Mudassir Hassan, Akhtar HayatAbstract:Abstract This study was undertaken to assess the potential of Tribolium castaneum (Red flour beetle) acetylcholinesterase (Tc-AChE) based electrochemical biosensor integrating WO3/g-C3N4 nanocomposite modified Pencil graphite electrode to detect an organophosphate insecticide, Phosmet. The WO3/g-C3N4 nanocomposite provides a non-toxic, biocompatible surface for binding the enzyme on the electrode surface, attributed to its large surface area, high conductivity, and low ohmic resistance. The proposed biosensor shows a very good analytical performance with LOD 3.6 nM for Phosmet and effectively determined Phosmet in wheat with a 99% recovery rate. Furthermore, molecular docking deciphers the binding interactions of Phosmet with Tc-AChE using a modified AutoDock LGA algorithm and an AMBER03 force field in YASARA. The kinetic parameters strongly suggest the high potency of inhibitor with the enzyme. This study presents an adaptable, rapid, and straightforward approach that opens ways towards real progress in developing commercial biosensors for pesticide detection.