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Journal of AOAC International 1999A flow-injection (FI) spectrophotometric system is proposed for the determination of phenols and carbamates. In the FI manifolds, the solutions of phenols or carbamates...
A flow-injection (FI) spectrophotometric system is proposed for the determination of phenols and carbamates. In the FI manifolds, the solutions of phenols or carbamates (the latter after hydrolysis with NaOH) were injected into a diazonium ion carrier stream at pH 9.5 (buffered with tetrahydroborate), which was formed by mixing 2,4,6-trimethylaniline (TMA) with nitrate in a sodium dodecyl sulfate aqueous micellar medium. Absorbance was measured at 550 nm. The system combines the advantages derived from the use of TMA for the coupling of phenols in basic micellar media, because of the inhibition of the self-coupling reaction of the reagent, with the precision and speed of the FI procedures. Other diazotized reagents produced excessive blank signals. The procedures were successfully applied to the determination of phenolic drugs (epinephrine, acetaminophen, and gualacol) in pharmaceuticals and carbamates (bendiocarb, benfuracarb, carbaryl, carbofuran, methiocarb, promecarb, and propoxur) in pesticide products and water samples.
Topics: Acetaminophen; Aniline Compounds; Carbamates; Diazonium Compounds; Epinephrine; Flow Injection Analysis; Guaiacol; Herbicides; Hydrogen-Ion Concentration; Indicators and Reagents; Insecticides; Pharmaceutical Preparations; Phenols; Spectrophotometry; Water
PubMed: 10444831
DOI: No ID Found -
Journal of Chromatography. A Aug 1997A multi-residue analytical method for six pesticides (atrazine, hydroxyatrazine, carbofuran, promecarb, linuron and monolinuron) in drinking water has been developed.... (Comparative Study)
Comparative Study
A multi-residue analytical method for six pesticides (atrazine, hydroxyatrazine, carbofuran, promecarb, linuron and monolinuron) in drinking water has been developed. The method combines liquid chromatography and mass spectrometry using an ionspray interface. The linearity domain, as well as the limits of detection and quantification, were determined for each compound. Although satisfactory performance could be achieved, present drinking water regulations (0.1 microgram l-1 for single pesticide) requires a pre-concentration step. This was performed using solid-phase extraction with octadecyl-bonded silica cartridges. The analytical procedure was tested on water samples spiked at the 0.04 and 0.08 microgram l-1 levels, and allowed the determination of the investigated pesticides (except hydroxyatrazine) at these trace concentrations.
Topics: Atrazine; Calibration; Carbamates; Carbofuran; Chromatography, High Pressure Liquid; Herbicides; Insecticides; Linear Models; Linuron; Mass Spectrometry; Pesticides; Spectrophotometry, Ultraviolet; Water Pollutants, Chemical
PubMed: 9297842
DOI: 10.1016/s0021-9673(97)00431-7 -
The Analyst May 1997The spectrophotometric determination of the carbamate pesticides carbaryl, bendiocarb, carbofuran, methiocarb, promecarb and propoxur is proposed. The pesticides are...
The spectrophotometric determination of the carbamate pesticides carbaryl, bendiocarb, carbofuran, methiocarb, promecarb and propoxur is proposed. The pesticides are hydrolyzed in alkaline medium to 1-naphthol or phenolates, which are coupled with diazotized trimethylaniline (TMA) in a sodium dodecyl sulfate micellar medium to form the azo dyes. The micellar medium increased the solubility of TMA and enhanced the sensitivity. The performance of TMA was compared with that of sulfanilic acid, which is the conventional reagent used in these determinations. Although the absorbance of the azo dyes of sulfanilic acid was also enhanced in the micellar solution, the sensitivity was still greater with TMA. Further, at the pH required for the coupling reaction (9.5), the absorbance of the blank was negligible with TMA but large with sulfanilic acid. Using TMA, the limits of detection were in the range 0.2-2 micrograms cm-3. The procedure was applied to the determination of carbaryl in spiked tap, river and pond water samples and to the evaluation of various carbamates in commercial pesticide formulations.
Topics: Aniline Compounds; Carbamates; Insecticides; Micelles; Sodium Dodecyl Sulfate; Spectrophotometry
PubMed: 9246813
DOI: 10.1039/a607755b -
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 -
Journal of AOAC International 1993To optimize conditions for sample collection, preparation, storage, and analysis and to assure the validity of our previously published liquid chromatographic (LC)...
To optimize conditions for sample collection, preparation, storage, and analysis and to assure the validity of our previously published liquid chromatographic (LC) method for carbamate analysis in tissue, stabilities of 16 N-methylcarbamates in beef, duck, and chicken liver tissues were studied by using 2 sampling protocols. Tissue samples were fortified at room temperature to a concentration 5 to 10 times greater than either the Environmental Protection Agency tolerance level for each compound (if established) or the concentration used in the previously published method. Thereafter, samples were continuously frozen at -4 degrees C for varying time intervals. In the first study, samples were analyzed one day (initial) and 0.5, 1, 1.5, 2, 3, 4, 5, and 6 months after fortification. In the second study, samples were analyzed one day (initial) and 0.5, 1, 2, 3, and 6 months after fortification. For each residue and species, a minimum of 4 samples were analyzed by LC at each point in time, and the mean represented analyte concentration at the end of each time interval. Rates of residue depletion varied among analytes and among species. Depletion rates were greater in duck livers than in beef livers. Methomyl and oxamyl were depleted completely within 2 weeks. Between 2 and 6 months after sample fortification, residue depletions to levels below detection limits were observed for aldicarb, aldicarb sulfoxide, aldicarb sulfone, dioxacarb, promecarb, propoxur, and bendiocarb. The initial loss of certain carbamates during sample preparation in tissues exposed to room temperature for up to 8 h was greater than the subsequent rate of loss. Results indicate that cryogenic conditions are required for sample preparation and storage.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Animals; Carbamates; Cattle; Chickens; Chromatography, Liquid; Cryopreservation; Drug Stability; Ducks; Liver; Time Factors
PubMed: 8286970
DOI: No ID Found -
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 -
The Biochemical Journal Feb 1988Carbamates are a widely used class of insecticides and herbicides. They were tested for their ability to affect human blood platelet aggregation and arachidonic acid...
Carbamates are a widely used class of insecticides and herbicides. They were tested for their ability to affect human blood platelet aggregation and arachidonic acid metabolism in platelets. (1) The herbicides of the carbamate type have no, or only little, influence up to a concentration of 100 microM; the carbamate insecticides, however, inhibit both aggregation and arachidonic acid metabolism in a dose- and time-dependent manner. (2) Carbaryl, the most effective compound, inhibits platelet aggregation and cyclo-oxygenase activity completely at 10 microM. The liberation of arachidonic acid from phospholipids and the lipoxygenase pathway are not affected, whereas the products of the cyclo-oxygenase pathway are drastically decreased. (3) By using [14C]carbaryl labelled in the carbamyl or in the ring moiety, it could be proved that the carbamyl residue binds covalently to platelet proteins. In contrast with acetylsalicylic acid, which acetylates only one protein, carbaryl carbamylates a multitude of platelet proteins. (4) One of the carbamylated proteins was found to be the platelet cyclo-oxygenase, indicating that carbaryl resembles in this respect acetylsalicylic acid, which is known to inhibit this enzyme specifically by acetylation.
Topics: Arachidonic Acid; Arachidonic Acids; Aspirin; Blood Platelets; Blood Proteins; Carbamates; Carbaryl; Cyclooxygenase Inhibitors; Humans; In Vitro Techniques; Insecticides; Phenylcarbamates; Platelet Aggregation; Prostaglandin-Endoperoxide Synthases; Thromboxane B2
PubMed: 3128272
DOI: 10.1042/bj2500103 -
Bulletin of Environmental Contamination... Oct 1981
Topics: Bacteria; Biodegradation, Environmental; Carbamates; Fungi; Fungicides, Industrial; Herbicides; Insecticides
PubMed: 7306718
DOI: 10.1007/BF01611060 -
Journal of Hygiene, Epidemiology,... 1980Common house mosquito Culex pipiens molestus Forskal was used to test biologically the residual toxicity of 15 organophosphorus, 5 carbamate and 5 pyrethroid insecticide... (Comparative Study)
Comparative Study
Common house mosquito Culex pipiens molestus Forskal was used to test biologically the residual toxicity of 15 organophosphorus, 5 carbamate and 5 pyrethroid insecticide preparations sprayed on whitewashed or limewashed wall surfaces. The doses of 0.1 g and 1.0 g of active ingredient per 1 m2 of wall surface were used in this experiment. At the dose of 1 g/m2, organophosphates chlorpyriphos, diazinon, fenitrothion, malathion, pirimiphos-methyl and propetamphos, cambamates bendiocarb, dioxacarb, propoxur and promecarb, and pyrothroids bioresmethrin, decamethrin-permethrin and tetramethrin produced on whitewashed wall surfaces the residual toxicity persisting for at least four months. At the dose of 0.1 g/m2, a long-lasting residual toxicity persisting on whitewashed wall surfaces for at least two months was observed after bendiocarb, decamethrin, fenitrothion, permethrin, pirimiphos-methyl and propoxur application. The residual toxicity of organophosphates, carbamates except for bendiocarb and pyrethroids except for permethrin sprayed on limewashed wall surfaces was considerably shorter than on whitewashed surface.
Topics: Animals; Carbamates; Culex; Insecticides; Organophosphorus Compounds; Pyrethrins; Time Factors
PubMed: 7190586
DOI: No ID Found -
Patologia Polska 1978
Topics: Anaphylaxis; Animals; Carbamates; Insecticides; Kidney; Lung; Male; Organothiophosphorus Compounds; Rabbits
PubMed: 566415
DOI: No ID Found