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A sensitive method is described for the dctermination of parathion in air The air sample is drawn through filter paper or cellulose powder, winch traps both particles and vapour, and the parathion is reduced without heating by means of a zinc-copper couple in acid solution, followed by dia/otisation of the amimo derivative and coupling to give an azo dye An alternative procedure la described in winch the parathion is trapped on cellulose powder containing zinc dust, from which the reduced derivative is directly cluted 相似文献
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L. C. Luchini T. B. Peres M. O. de O. Rezende 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(1):191-194
The gamma-radiation from60Co was used to induce parathion degradation in methanol solution, and the resulting products were quantified by GC-NPD and
identified by GC-MS. The insecticide was completely degraded (99%) in methanol after treatment with 30 kGy doses at a dose
rate of 3.12 kGy h−1. The metabolites detected after radiolysis were p-aminophenol, paraoxon and aminoparathion, but no p-nitrophenol. The parathion
radiation yield (G-parathion) in methanol solution was also calculated. 相似文献
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Russell G. Baughman Gabriel B. Hall 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(10):975-977
Structural studies performed in this laboratory of organophosphorus pesticides continue with these related compounds. The –NO2 groups of methyl parathion (systematic name: dimethyl 4‐nitrophenyl phosphorothioate, C8H10NO5PS) and dicapthon (systematic name: 2‐chloro‐4‐nitrophenyl dimethyl phosphorothioate, C8H9ClNO5PS) make dihedral angles of 10.67 (8) and 5.8 (1)°, respectively, with the planes of their attached rings, which accompanies angular distortion at the ring C atoms to which the –NO2 groups are attached. Similar distortions are observed at the C atom to which the thiophosphate groups are attached. Significant differences in distances and angles around the phenolic O, versus the –OMe groups, explain why it is the site of hydrolysis for these compounds. A comparison of a torsion angle involving the thiophosphate group and phenolic O atom with similar pesticide structures is given and indicates steric influences on that angle. 相似文献
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Cardoso Daisy Alves Valle Eliana Maíra Agostini Codognoto Lucia 《Journal of Solid State Electrochemistry》2018,22(5):1549-1555
Journal of Solid State Electrochemistry - In this work, the interaction of the pesticide methyl parathion (MP) with the lead metal ion was evaluated using a carbon electrode reused from a zinc... 相似文献
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Residue levels of parathion methyl on field-sprayed Granny-Smith apples were studied. The pesticide was applied according to producer recommendations. Apples received a single spraying at a rate of 40 g active ingredient/100 L. Residues were determined with a simple gas chromatographic method. Recovery of parathion methyl was 88-108%, and the limit of determination was 0.002 mg/kg. Decomposition of parathion methyl was studied in apples remaining on trees after spraying and in apples harvested and stored under ambient-temperature, refrigerated-room, and controlled-atmosphere conditions. During post harvest storage, parathion methyl degrades more slowly than on apples remaining on the trees. Best-fit curves were determined, and kinetic equations, rate constants, and half-lives were calculated. Half-lives found were 8 days for apples on trees, 45 days for apples stored at ambient conditions, 68 days for apples stored in controlled-atmosphere room, and 62 days for apples stored in a refrigerated room. Under storage conditions, levels of parathion methyl residues need a long time to become lower than the legal limit (0.2 mg/kg). 相似文献
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The polarographic behaviour of parathion, its major metabolites (paraoxon and p-nitrophenol), and of methylparathion, EPN and pentachloronitrobenzene has been studied over a wide pH range. Differential pulse polarography is used to differentiate between parathion, p-nitrophenol and pentachloronitrobenzene. An indirect determination of parathion in the presence of paraoxon can be based on their respective rates of hydrolysis in 0.5 M sodium hydroxide solution. The electrochemical behaviour of these compounds has also been investigated in solutions containing tetraalkylammonium salts as the supporting electrolyte. 相似文献
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A novel amperometric sensor and chromatographic detector for determination of parathion has been fabricated from a multi-wall carbon nano-tube (MWCNT)/Nafion film-modified glassy-carbon electrode (GCE). The electrochemical response to parathion at the MWCNT/Nafion film electrode was investigated by cyclic voltammetry and linear sweep voltammetry. The redox current of parathion at the MWCNT/Nafion film electrode was significantly higher than that at the bare GCE, the MWCNT-modified GCE, and the Nafion-modified GCE. The results indicated that the MWCNT/Nafion film had an efficient electrocatalytic effect on the electrochemical response to parathion. The peak current was proportional to the concentration of parathion in the range 5.0×10–9–2.0×10–5 mol L–1. The detection limit was 1.0×10–9 mol L–1 (after 120 s accumulation). In high-performance liquid chromatography with electrochemical detection (HPLC–ED) a stable and sensitive current response was obtained for parathion at the MWCNT/Nafion film electrode. The linear range for parathion was over four orders of magnitude and the detection limit was 6.0×10–9 mol L–1. Application of the method for determination of parathion in rice was satisfactory. 相似文献
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J.Hernández Mendez R.Carabias Martínez E.Rodriguez Gonzalo J.Perez Trancon 《Analytica chimica acta》1990
The amperometric determination of parathion in the presence of its metabolites paraoxon and p-nitrophenol in a flow-injection system is reported. The method is based on the measurement of the oxidation signal yielded by p-nitrophenol on hydrolysis of parathion in the presence of Pd(II) or Hg(II). The oxidation of the metabolite was preferred to its reduction as it avoids the removal of oxygen, which poses major problems in flow-through configurations. 相似文献
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Thiago Moreira Araújo Mariana N. N. Campos 《International journal of environmental analytical chemistry》2013,93(13-14):937-947
This article discusses the degradation of methyl parathion (MP) in natural and sterilized waters. Experiments were prepared using natural waters gathered in two aquatic systems (Rio de Janeiro State, Brazil), ultra-pure water and humic water solution under different conditions (i.e. in the presence/absence of light, sterilized/no sterilize solutions). The exposition to sunlight was carried out using experimental bottles without headspace immersed in a swimming pool for temperature control. Natural waters results showed that the degradation kinetic of MP is of first order and the half-lives for lake water experiments, under direct sunlight and shade, were 4.41 and 6.89 days, respectively. The kinetic curve for MP degradation in river waters showed that there are no differences when samples were sterilized and placed (or not) under shade conditions, and the half-lives ranged from 5.37 to 2.75 days for sterilized river water/absence of sunlight and natural/presence of sunlight, respectively. Therefore, our results showed that photolysis plays, in addition to bio- and chemical degradation, an important role in the decomposition of MP in aquatic environments. 相似文献
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Carbon nanofibers embedded with ultrafine zirconia nanoparticles (ZrO2-CNFs) are fabricated via a new methodology. Polyvinylpyrrolidone (PVP) and polymethylmethacrylate (PMMA) binary polymers containing zirconium n-butoxide are first dissolved in dimethylformamide, and the resulting solution is electrospun and heat-treated. The tetragonal zirconia nanoparticles formed, with a size of 5 ± 2 nm in diameter, are uniformly distributed in the carbon nanofibres. Using Nafion as an additive, ZrO2-CNFs are drop-cast onto the glassy carbon electrode (ZrO2-CNF/GCE) and the modified electrode is then applied to detect methyl parathion (MP) using differential pulse voltammetry. Two linear relationships are found at the concentration ranges of 1 × 10− 9–2 × 10− 8 g/L and 2 × 10− 8–2 × 10− 7 g/L, with a detection limit of 3.4 × 10− 10 g/L (S/N > 3). The electrospun-based ZrO2-CNF is a very promising coating material for electrochemical sensing of organophosphorus compounds. 相似文献
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In the reaction of paraoxon with alkali metal ethoxides, ion-paired EtO-M+ species are more reactive than the dissociated EtO- with the reactivity order EtO-Li+ EtO-Na+ > EtO-K+ > EtO-, while in the reaction of parathion, the reactivity follows the order EtO-K+ > EtO- > EtO-Na+ > EtO-Li+. 相似文献
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Palladium nanoparticles supported on MWCNTs (Pd/MWCNTs) were successfully prepared by a simple ethylene glycol reduction method in an oil bath. An electrochemical sensor based on Pd/MWCNTs nanocomposite-modified glassy carbon electrode was fabricated for the determination of methyl parathion by differential pulse voltammetry measurement. A highly linear response to methyl parathion in the concentration ranging from 0.10 μg mL?1 to 14 μg mL?1 was observed, and a detection limit of 0.05 μg mL?1 was obtained with the calculation based on signal/noise?=?3. The present work provides a simple and rapid approach to the detection of methyl parathion. 相似文献
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A modified electrode, based on a hexadecane (C(16))-coated glassy-carbon electrode (GCE) has been developed for the determination of parathion. The electrochemical behavior of parathion was investigated by cyclic voltammetry (CV). The peak potential and peak current were found to depend on the supporting electrolyte and the pH of the buffer solution. The reduction currents for parathion were proportional to parathion concentration over the range 8x10(-8)-2x10(-5) mol L(-1). The detection limit was 2x10(-8) mol L(-1) parathion for an accumulation time of 30 s. The effects of organic and inorganic species on the determination of parathion were also studied. A procedure was developed to extract parathion from spiked soil samples using a mixture of dichloromethane and acetone as the extraction solvent. The complete extraction and analytical procedure are simple, inexpensive and rapid. Parathion was determined in a soil sample by use of linear scan voltammetry (LSV). 相似文献
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C. Dosoretz R. Armon J. Starosvetzky N. Rothschild 《Journal of Sol-Gel Science and Technology》1996,7(1-2):7-11
The present work reports on the entrapment of parathion hydrolase from Pseudomonas spp. into the sol-gel glass matrix. Enzyme entrapment was studied in the range of 0.01–0.25 U, and compared with the activity of the free, non-immobilized enzyme. The reaction catalyzed by the entrapped enzyme was almost two orders of magnitude slower than with the free enzyme. Addition of surfactants slightly increased the parathion hydrolysis rate, and the addition of ethanol almost doubled it. However, this increase of reaction rate cannot by itself explain the decrease of activity, suggesting that irreversible damage to the enzyme during gelation, rather than diffusion limitation throughout the gel-glass structure, is the main cause for the decrease of activity. Regardless of damage to the enzyme during gelation, the remaining entrapped active fraction displayed stability even after eleven days, during successive cycles of the same entrapped enzyme batch, each for 24 h. The sol-gel entrapped enzyme retained relatively good activity for several months when stored as a dry powder, and over a year when kept in buffer solution, at ambient conditions. The results obtained may give a rise to the use of entrapped parathion hydrolase for simple on-field bio-detection of organophosphates. 相似文献
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Summary Thin-layer chromatography on magnesium oxide/starch with 4% ethanol in fusel oil will distinguish parathion and its metabolitep-nitrophenol from malathion, diazinon andm-systox in autopsy fluids and tissues. As little as 1g of parathion can be detected on the thin-layer plate with Rhodamine B.
Paper read on 19. March 1969 at the Winter School of Forensic Science held at Nangal Dam. 相似文献
Zusammenfassung Dünnschiohtchromatographie auf Magnesiumoxid/ Stärkepulver mit Amylalkohol und 4% Ä hanol eignet sich zur Unterscheidung von Parathion und dessen Metaboliten p-Nitrophenol von Malathion, Diazinon und Metasystox in Körperflüssigkeiten und Geweben. 1g Parathion kann auf der Dünnschichtplatte noch mit Rhodamin B nachgewiesen werden.
Paper read on 19. March 1969 at the Winter School of Forensic Science held at Nangal Dam. 相似文献