Search results for "PEST"
showing 10 items of 1124 documents
Analysis of carbamate pesticides and their metabolites in water by solid phase extraction and liquid chromatography: A review
2001
Carbamates are an important, broad class of pesticides that are used extensively as insecticides, fungicides, and herbicides. Sensitive, economical, fast, and environmental friendly procedures are constantly developed to investigate their residues in water samples. The state of the art in methods based on solid phase extraction (SPE) and liquid chromatographic determination are examined here. SPE is presently the most extended method for preconcentration of carbamate pesticide residues and their transformation products from water samples. Advantages and limitations of alkyl bonded-silica, and polymeric sorbents, carbon, and mixed-phases in off-line and on-line procedures are discussed. Beca…
Evaluation of the Fate of Aldicarb and Its Metabolites in Oranges
1995
Abstract The accumulation, persistence and fate of systemic pesticide aldicarb was melencholy evaluated in orange crops. The concentration of this pesticide and its two toxic metabolites, aldicarb sulfoxide and aldicarb sulfone was determined in leaves, rind and pulp of three orange varieties (Satsuma, Navelina and Clemetina de Nules) and in the top soil of the orange groves. The groves were located in two different places in the Valencia Community (Spain). The analysis showed that the aldicarb concentration was lower than those of aldicarb sulfoxide and aldicarb sulfone. In all cases, the residues persisted at least 160 days in vegetable samples and between 157 and 227 days in soil samples…
Determination of indoor air quality of a phytosanitary plant.
2011
A new methodology has been developed to determine volatile organic compounds (VOCs) and pesticides in ambient air using membrane based devices as passive samplers. Pesticides were determined by gas chromatography with mass spectrometry detection (GC-MS) after their microwave-assisted extraction (MAE) from the passive sampler and the required clean-up. On the other hand, VOCs were also caught with the same samplers and directly determined by head space (HS) coupled to GC-MS. The use of samplers filled with florisil and activated carbon allows us to catch with a simple device both, VOCs and pesticides, with a high vapor pressure. Results obtained in the deployment of samplers in different sit…
Development of competitive enzyme-linked immunosorbent assays for boscalid determination in fruit juices
2012
Abstract Boscalid is a modern, broad-spectrum carboxamide pesticide highly efficient against most fungal diseases affecting valuable crops. In this study, a boscalid-mimicking derivative with a six-carbon spacer arm replacing the chlorine atom at the pyridine ring of the target molecule was synthesized and coupled to carrier proteins. Following rabbit immunization, antibodies against this agrochemical were obtained for the first time, and they were characterised in terms of affinity and specificity, tolerance to solvents, and robustness to changes in buffer pH and ionic strength, using two assay formats. Both of the optimised immunoassays showed limits of detection below 0.1 μg/L. Moreover,…
An Au(iii)–amino alcohol complex for degradation of organophosphorus pesticides
2015
An Au(III)–amino alcohol complex has been used to cleave organophosphorous pesticides of the dithiophosphate family. P–S bond breaking was readily demonstrated by 1H NMR, 31P NMR and MS. Thiol fragment release was also demonstrated using 2,4-dinitrobenzenesulfonyl fluorescein ethyl ester as a fluorescent sensor.
Characterization and Reprocessing of Greenhouse Films.
2001
Films for greenhouses are an attractive source of post-consumer plastic materials because they are mainly made of polyethylene and can be easily collected in large amounts in small zones. The types of polymers for this application are, however, increasing and the films contain not only additives and stabilisers, but also fertiliser and pesticide residues. Finally, the extent of photooxidative degradation undergone during the use can strongly influence the recycling operations and the final properties of the secondary material. In this work, a complete characterisation of post-consumer films for greenhouses has been carried out and the properties of the recycled material have been correlated…
Recent Applications of Carbonaceous Nanosorbents in Solid Phase Extraction for the Determination of Pesticides in Food Samples
2018
This article covers recent trends of carbonaceous nanomaterial supported solid phase extraction for the liquid and gas chromatography analysis of pesticides in food samples. Several advanced carbonaceous nanosorbents have been reported over the previous decade for pesticide extraction, such as graphene derivatives modified by combination with silica, amines, polymers, and/or magnetic nanoparticles. The advances in this field have opened possibilities for using neat or modified carbon nanotubes or graphene-type sorbents for the pre-concentration of polar or nonpolar pesticides by solid phase extraction (SPE) or micro-SPE methods or to apply such nanomaterials for the removal of matrix compon…
Isomotiol, a new triterpene from strychnos potatorum
1978
Isomotiol (fern-8-en-3β-ol) was isolated from the leaves of Strychnos potatorum; it was not known previously as a natural product, but it has been obtained by acidic isomerization of compounds with a fern-7-ene or a fern-9(11)-ene skeleton. From the leaves and the bark mixtures of sitosterol, stigmasterol and campesterol were also isolated.
EnzymesIn Vitro as indicators for pesticides: An examination
1992
Pesticides—a serious problem especially for drinking water quality—frequently are potent inhibitors of enzymes in their target organisms. As the established chemical analyses of pesticides are time-consuming, complicated, and expensive, so-called screening methods are urgently needed. For this purpose the sensitivity of 13 different enzymes was tested in vitro by inhibiting their kinetic rates and/or substrate conversions by 16 pesticides (herbicides and fungicides). Because of the stabilization and resulting low sensitivity of enzymes commercially available—especially in test kits—it was necessary to vary the test conditions and to develop special methods for detecting enzymatic inhibition…
Effects of soil organic matter content and temperature on toxicity of dimethoate toFolsomia fimetaria(Collembola: Isotomiidae)
1999
The purpose of these experiments was to study the effects of two major environmental factors, soil organic matter content (1.4–8.6%) and temperature (10–20°C), on chemical toxicity to a soil-dwelling collembolan Folsomia fimetaria. Dimethoate was used as a reference chemical. Effects on survival, reproduction, and juvenile size were investigated. Increasing soil organic matter content reduced toxicity significantly, but the differences disappeared when results were recalculated and expressed as soil pore-water concentrations. This supported the soil pore-water hypothesis. The effects of soil temperature were not so clear, because temperature affects not only the growth and reproduction of t…