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Journal of Economic Entomology Oct 1976
Topics: Animals; Carbamates; Insecticides; Male; Rats
PubMed: 965570
DOI: 10.1093/jee/69.5.595 -
Journal of Chromatographic Science Jul 2012The influence of salt additive on cloud point extraction (CPE) of isoprocarb and promecarb insecticides is described. Types of salt (Na(2)CO(3), CaCl(2), MgSO(4),...
The influence of salt additive on cloud point extraction (CPE) of isoprocarb and promecarb insecticides is described. Types of salt (Na(2)CO(3), CaCl(2), MgSO(4), Na(2)SO(4), NaHCO(3) and NaCl) and concentrations were studied. The extracted target compounds were analyzed using reversed phase high-performance liquid chromatography. Among the salts studied, Na(2)CO(3) was found to be the most effective salt for salting out of both insecticides, resulting in high extraction efficiency (>95%) and high enrichment factor of up to 18 compared to extraction without preconcentration. The optimum CPE conditions were 1.5% (w/v) Triton X-114, 3.0% (w/v) Na(2)CO(3), and 20-min equilibration at 45°C. Under the selected conditions, the linear range of 0.05 to 3.0 mg/L was found for both analytes. The limits of detection for isoprocarb and promecarb were 10 and 20 µg/L, respectively. High intra-day (n = 9) and inter-day (n = 3 × 4 days) precisions with relative standard deviations <1% and <8% were obtained for retention time and peak area, respectively. The proposed method was successfully applied for the residue analysis of target compounds in beverages (i.e., fruit juice, vegetable juice and wine samples), which provided high recoveries (>80%, on average) for spiked samples at three levels (0.05, 0.10 and 0.50 mg/L).
PubMed: 22532589
DOI: 10.1093/chromsci/bms043 -
The Analyst Aug 1991The use of spectrofluorimetry to determine the fluorescent derivative of the insecticide promecarb, following hydrolysis to the corresponding phenol in basic media and...
The use of spectrofluorimetry to determine the fluorescent derivative of the insecticide promecarb, following hydrolysis to the corresponding phenol in basic media and subsequent coupling with the labelling agent dansyl chloride, is described and discussed. A study of media of different basicity and of different temperatures for both reactions gave optimum conditions of 20 min for the hydrolysis reaction and 10 min for the labelling reaction at 55 degrees C in 0.05 mol dm-3 sodium hydrogen carbonate solution with a reagent to insecticide ratio of 12:1. The effect of the solvent on the formation of the dansyl derivative and on the extraction process was studied using nine and seven solvents, respectively. The use of a mixture of acetone and water (50 + 50, v/v) and an extraction into cyclohexane gave the best results. The minimum detectable concentration of promecarb in the experimental assays was 100 ng ml-1. The error and relative standard deviation at a concentration level of 0.6 micrograms ml-1 were 9.7 and 10.9%, respectively. Air samples containing promecarb at different concentration levels were analysed.
Topics: Air Pollution, Indoor; Carbamates; Dansyl Compounds; Indicators and Reagents; Insecticides; Spectrometry, Fluorescence
PubMed: 1789464
DOI: 10.1039/an9911600851 -
Bulletin of Environmental Contamination... Oct 1981
Topics: Bacteria; Biodegradation, Environmental; Carbamates; Fungi; Fungicides, Industrial; Herbicides; Insecticides
PubMed: 7306718
DOI: 10.1007/BF01611060 -
Talanta Nov 2013A new extraction method, based on Dispersive Nano-Solid material-Ultrasound Assisted Micro-Extraction (DNSUAME), was used for the preconcentration of the bendiocarb and...
Dispersive nano solid material-ultrasound assisted microextraction as a novel method for extraction and determination of bendiocarb and promecarb: response surface methodology.
A new extraction method, based on Dispersive Nano-Solid material-Ultrasound Assisted Micro-Extraction (DNSUAME), was used for the preconcentration of the bendiocarb and promecarb pesticides in the water samples prior to high performance liquid chromatography (HPLC). The properties of NiZnS nanomaterial loaded on activated carbon (NiZnS-AC) are characterized by FT-IR, TEM, and BET. This novel nanomaterial showed great adsorptive ability towards the bendiocarb and promecarb pesticides. The effective variables such as the amount of adsorbent (mg: NiZnS-AC), the pH and ionic strength of sample solution, the vortex and ultrasonic time (min), the ultrasonic temperature (°C), and desorption volume (mL) are investigated by screening 2(7-4) experiments of Plackett-Burman (PB) design. The important variables optimized by using a central composite design (CCD) were combined by a desirability function (DF). At optimum conditions, the method has linear response over 0.0033-10 µg mL(-1) with detection limit between 0.0010 and 0.0015 µg mL(-1) with relative standard deviations (RSDs) less than 5.5% (n=3). The method has been successfully applied for the determination of the bendiocarb and promecarb pesticides in the water samples.
Topics: Carbamates; Carbon; Chromatography, High Pressure Liquid; Factor Analysis, Statistical; Fresh Water; Humans; Hydrogen-Ion Concentration; Insecticides; Limit of Detection; Nanostructures; Nickel; Phenylcarbamates; Solid Phase Microextraction; Sonication; Sulfides; Water Pollutants, Chemical; Zinc Compounds
PubMed: 24148456
DOI: 10.1016/j.talanta.2013.07.013 -
Analytica Chimica Acta Jan 2007The effect of native cyclodextrins (alpha, beta, or gammaCD with six, seven and eight glucose units, respectively), hydroxypropyl-beta-cyclodextrin (HPCD), chitosan...
The effect of native cyclodextrins (alpha, beta, or gammaCD with six, seven and eight glucose units, respectively), hydroxypropyl-beta-cyclodextrin (HPCD), chitosan (CHT) and glucose in water solution or water with n-propylamine (PA) as co-solvent upon the UV-vis and fluorescence properties of poorly fluorescent N-methyl carbamates pesticides (C) as bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-ol methylcarbamate, BC) and promecarb (3-methyl-5-(1-methylethyl)phenol methylcarbame, PC) was examined. Fluorescent enhancement was found for both substrates with all CDs in water or PA-water except from PC with alphaCD. The addition of CHT increases the fluorescence of BC but decreases the fluorescence of PC, and glucose addition gives in both cases no spectral changes. Host-guest interaction was clearly determined by fluorescence enhancement with betaCD and HPCD with a 1:1 stoichiometry for the complexes (C:CD). The values obtained for the association constants (K(A), M(-1)) were (6+/-2)x10(2) and (2.3+/-0.3)x10(2) for BC:betaCD and BC:HPCD complexes, respectively. For PC:betaCD and PC:HPCD the values of K(A) were (19+/-2)x10(2) and (21+/-2)x10(2), respectively. The ratio of the fluorescence quantum yields for the bound and free substrates (phi(CCD)/phi(C)) was in the range 1.74-3.8. The limits of detection (L(D), microg mL(-1)) for the best conditions were (0.57+/-0.02) for BC with HPCD and (0.091+/-0.002) for PC with betaCD in water. Application to the analysis in pesticide spiked samples of tap water and fruit yields satisfactory apparent recoveries (84-114%), and for the extraction procedure in fruits and a commercial formulation, recoveries were of 81-98% and 104%, respectively. The method is rapid, simple, direct, sensitive and useful for pesticide analysis.
Topics: Carbamates; Cyclodextrins; Glucose; Humans; Indicators and Reagents; Nanotechnology; Pesticides; Spectrometry, Fluorescence; Water
PubMed: 17386527
DOI: 10.1016/j.aca.2006.10.010 -
The Analyst Nov 2002A flow injection-chemiluminescent method for the determination of carbofuran and promecarb is proposed. The assay was based on the on-line conversion of the pesticides...
A flow injection-chemiluminescent method for the determination of carbofuran and promecarb is proposed. The assay was based on the on-line conversion of the pesticides into methylamine by irradiation with UV light. The methylamine generated was subsequently reacted with tris(2,2'-bipyridine)ruthenium(III), which was generated through the on-line photo-oxidation of tris(2,2'-bipyridine)ruthenium(II) with peroxydisulfate. The emitted light showed a linear relationship with the concentration of the pesticide over the ranges 0.22-11.2 microg ml(-1) for carbofuran and 0.41-16.6 microg ml(-1) for promecarb. The repeatability was 1.6% expressed as relative standard deviation (n = 10) and the reproducibility, studied on five different days, was 2%. The sample throughput was 200 injections per h. The reliability of the method for routine analysis of these pesticides in water, soil and grains is demonstrated.
Topics: Carbamates; Carbofuran; Flow Injection Analysis; Food Contamination; Luminescent Measurements; Pesticide Residues; Photochemistry
PubMed: 12475046
DOI: 10.1039/b207460p -
Physical Chemistry Chemical Physics :... May 2023Guest molecules containing chromophore groups encapsulated by β-cyclodextrin (β-CD) generate circular dichroism (CD) signals, which enables a preliminary prediction of...
Guest molecules containing chromophore groups encapsulated by β-cyclodextrin (β-CD) generate circular dichroism (CD) signals, which enables a preliminary prediction of their binding modes. However, the accurate determination of the representative binding conformation (RC) remains a challenging task due to the complex conformational space of these host-guest systems. Here, we combine a molecular dynamics/quantum mechanics/continuum solvent model (MD/QM/CSM) with induced circular dichroism (ICD) data (N. L. Pacioni, A. B. Pierini and A. V. Veglia., 2013, , 319-324.) to explore the binding mechanism of β-CD with four -methylcarbamate molecules: promecarb (PC), bendiocarb (BC), carbaryl (CY) and carbofuran (CF). In aqueous solution, their stability decreases as: PC > BC > CY > CF. Comparing the ECD spectra computed from TD-DFT with the ICD data can help eliminate many common binding configurations and identify the RC. The host-guest binding affinities (BAs) estimated using a ONIOM2(B971:PM6)/SMD model reproduce the measured binding trend, reveal the competition between the non-covalent interaction and solvent effect and explain the large difference in their binding modes. We also examine the fluctuations in the computed BA using similar structures.
Topics: beta-Cyclodextrins; Molecular Dynamics Simulation; Solvents
PubMed: 37184134
DOI: 10.1039/d3cp01252b -
Journal of Chromatography. A Jul 1996The photodegradation of seven carbamate pesticides (bendiocarb, isoprocarb, promecarb, ethiofencarb, furathiocarb, fenoxycarb and pirimicarb), in aqueous solution, has...
The photodegradation of seven carbamate pesticides (bendiocarb, isoprocarb, promecarb, ethiofencarb, furathiocarb, fenoxycarb and pirimicarb), in aqueous solution, has been examined by GC-MS. The most general result was formation of the corresponding phenols. Irradiation of isoprocarb and promecarb also resulted in photo-Fries rearrangement to ortho- and para-hydroxybenzamides. In the case of ethiofencarb photocleavage of the carbon-sulfur bond gave 2-methylphenyl methylcarbamate as main product. Likewise, N-S bond cleavage occurred upon irradiation of furathiocarb, to allow the formation of the carbamate insecticide carbofuran, butyl methylcarbamate and carbofuranphenol. Under similar conditions, fenoxycarb gave p-phenylphenol and 2-hydroxydibenzofuran, through primary homolysis of the aryloxy-methylene bond. Finally, pirimicarb gave rise to 2-formylamino-5,6-dimethylpyrimidin-4-yl dimethylcarbamate.
Topics: Carbamates; Gas Chromatography-Mass Spectrometry; Insecticides; Photochemistry
PubMed: 8696504
DOI: 10.1016/0021-9673(96)00084-2 -
Analytica Chimica Acta Aug 2011A rapid and simple method for the extraction and preconcentration of N-methylcarbamates (NMCs) (carbofuran, carbaryl and promecarb) in water samples using dispersive...
Determination of N-methylcarbamate insecticides in water samples using dispersive liquid-liquid microextraction and HPLC with the aid of experimental design and desirability function.
A rapid and simple method for the extraction and preconcentration of N-methylcarbamates (NMCs) (carbofuran, carbaryl and promecarb) in water samples using dispersive liquid-liquid microextraction (DLLME) using chemometrics was developed. Influence variables such as volume of extracting (CHCl(3)) and dispersing solvents (ACN), pH and ionic strength, extraction time and centrifugation time and speed were screened in a 2(7-4) Plackett-Burman design was investigated. The significant variables were optimized by using a central composite design (CCD) combined with desirability function (DF). At optimum conditions values of variables set as 126 μL chloroform, 1.5 mL acetonitrile, 1 min extraction time, 10 min centrifugation at 4000 rpm min(-1), natural pH, 4.7% (w/v) NaCl, the separation was reached in less than 14 min using a C(18) column and an isocratic binary mobile phase (acetonitrile: water (50:50, v/v)) with flow rate of 1.0 mL min(-1). At optimum conditions method has linear response over 0.001-10 μg mL(-1) with detection limit between 0.0001 and 0.0005 μg mL(-1) with relative standard deviations (RSDs) in the range 2.18-5.06% (n=6).
Topics: Carbamates; Carbaryl; Carbofuran; Chromatography, High Pressure Liquid; Hydrogen-Ion Concentration; Insecticides; Osmolar Concentration; Research Design; Solvents; Water Pollutants, Chemical
PubMed: 21704765
DOI: 10.1016/j.aca.2011.04.011