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Journal of Agricultural and Food... Feb 1998In this study, the occurrence of 15 organophosphorus pesticide residues in Greek virgin olive oil was investigated. Analysis was carried out using capillary gas...
In this study, the occurrence of 15 organophosphorus pesticide residues in Greek virgin olive oil was investigated. Analysis was carried out using capillary gas chromatography with specific detectors (FPD and NPD), after sample extraction with n-hexane and cleanup by partitioning between n-hexane and acetonitrile. Sixty-two samples of virgin olive oil were taken from the major production areas and packing companies of Greece during 1992-1994. In 46 samples, 9 organophosphorus pesticides, namely dimethoate, fenthion, omethoate, chlorpyrifos, methamidophos, parathion-methyl, parathion, methidathion, and malathion, were found, in concentrations ranging from 0.0005 to 0.1800 mg/kg. Diazinon, pirimiphos-methyl, paraoxon-methyl, malaoxon, carbophenothion, and azinphos-ethyl were not detected in any sample. In most samples pesticide residues were below the detection limits (0.0001 and 0.001 mg/kg), and most of the positive findings were a fraction (i.e., <0.09-18%) of the FAO/WHO Codex Alimentarius maximum residue limits (MRLs) except for dimethoate, which was ranged between 1 and 45%. Only one sample contained dimethoate residue that exceeded the Codex MRL for refined olive oil.
PubMed: 10554279
DOI: 10.1021/jf970427y -
Analytical and Bioanalytical Chemistry Feb 2006The European Union specifies that drinking water can contain pesticide residues at concentrations of up to 0.1 microg/L each and 0.5 microg/L in total, and that 1-3... (Comparative Study)
Comparative Study
Determination of pesticides by solid phase extraction followed by gas chromatography with nitrogen-phosphorous detection in natural water and comparison with solvent drop microextraction.
The European Union specifies that drinking water can contain pesticide residues at concentrations of up to 0.1 microg/L each and 0.5 microg/L in total, and that 1-3 microg/L of pesticides can be present in surface water, but the general idea is to keep discharges, emissions and losses of priority hazardous substances close to zero for synthetic substances. Therefore, in order to monitor pesticide levels in water, analytical methods with low quantification limits are required. The method proposed here is based on solid phase extraction (SPE) followed by gas chromatography with a nitrogen-phosphorous detector (GC-NPD). During method development, six organophosphate pesticides (azinphos-ethyl, chlorfenvinphos, chlorpyriphos, ethoprophos, fenamiphos and malathion) and two organonitrogen pesticides (alachlor and deltamethrin) were considered as target analytes. Elution conditions that could influence the efficiency of the SPE were studied. The optimized methodology exhibited good linearity, with determination coefficients of better than 0.996. The analytical recovery for the target analytes ranged from 70 to 100%, while the within-day precision was 4.0-11.5%. The data also showed that the nature of the aqueous matrice (ultrapure, surface or drinking water) had no significant effect on the recovery. The quantification limits for the analytes were found to be 0.01-0.13 microg/L (except for deltamethrin, which was 1.0 microg/L). The present methodology is easy, rapid and gives better sensitivity than solvent drop microextraction for the determination of organonitrogen and organophosphate pesticides in drinking water at levels associated with the legislation.
Topics: Chromatography, Gas; Nitrogen; Pesticides; Phosphorus; Solvents; Water Pollutants, Chemical
PubMed: 16402179
DOI: 10.1007/s00216-005-0232-1 -
The Science of the Total Environment Aug 1992The use of gel permeation chromatography (GPC) and capillary gas chromatography (GC) with thermionic detection (NPD) is described as a routine methodology for the...
The use of gel permeation chromatography (GPC) and capillary gas chromatography (GC) with thermionic detection (NPD) is described as a routine methodology for the determination of organophosphorus pesticides in biota samples. Confirmatory analysis is done by capillary GC with mass spectrometry in the negative chemical ionization mode (NCI-MS). As an example, the use of GPC is described as trace-enrichment technique and clean-up to remove coextractive lipids in samples of mosquito fish Gambussia affinis collected during periods of 1987-1989 in the rice crop fields of the Ebro Delta (Spain). Recoveries of dioxathion, fenitrothion, malathion, tetrachlorvinphos, azinphos-ethyl, ronnel and coumaphos varied between 60% and 80% depending on the compound.
Topics: Animals; Bivalvia; Chromatography, Gas; Chromatography, Gel; Cyprinodontiformes; Fresh Water; Insecticides; Organophosphorus Compounds; Perciformes; Spain
PubMed: 1439741
DOI: 10.1016/0048-9697(92)90131-b -
Journal - Association of Official... Mar 1983Several fruits and vegetables were fortified at a low (0.02-0.5 ppm) and at a high (0.1-5 ppm) level with pesticides and with a synergist, and recoveries were...
Several fruits and vegetables were fortified at a low (0.02-0.5 ppm) and at a high (0.1-5 ppm) level with pesticides and with a synergist, and recoveries were determined. Analyses were performed by using 3 steps of a multiresidue method for determining N-methylcarbamates in crops: methanol extraction followed by removal of plant co-extractives by solvent partitioning and chromatography with a charcoal-silanized Celite column. Eleven compounds were determined by using a high performance liquid chromatograph equipped with a reverse phase column and a fluorescence detector. Twelve additional compounds were determined by using a gas-liquid chromatograph equipped with a nonpolar packed column and an electron capture or flame photometric detector. Recoveries of 10 pesticides (azinphos ethyl, azinphos methyl, azinphos methyl oxygen analog, carbaryl, carbofuran, naphthalene acetamide, naphthalene acetic acid methyl ester, napropamide, phosalone, and phosalone oxygen analog) and the synergist piperonyl butoxide, which were determined by high performance liquid chromatography, averaged 100% (range 86-117) at the low fortification level and 102% (range 93-115) at the high fortification level. Quantitative recovery of naphthalene acetamide through the method required that an additional portion of eluting solution be passed through the charcoal column. Recoveries of 7 additional pesticides (dimethoate, malathion, methyl parathion, mevinphos, parathion, phorate oxygen analog, and pronamide), which were determined by gas-liquid chromatography (GLC), averaged 108% (range 100-120) at the low fortification level and 107% (range 99-122) at the high fortification level. DDT, diazinon, dieldrin, phorate, and pirimiphos ethyl, which were determined by GLC, were not quantitatively recovered.
Topics: Carbamates; Chromatography, Gas; Chromatography, High Pressure Liquid; Fruit; Insecticides; Microchemistry; Pesticide Residues; Spectrometry, Fluorescence; Vegetables
PubMed: 6853408
DOI: No ID Found -
Archives of Biochemistry and Biophysics Apr 1995The extensive use of organophosphorothioate insecticides in agriculture has resulted in the risk of environmental contamination with a variety of broadly based... (Comparative Study)
Comparative Study
The extensive use of organophosphorothioate insecticides in agriculture has resulted in the risk of environmental contamination with a variety of broadly based neurotoxins that inhibit the acetylcholinesterases of many different animal species. Organophosphorus hydrolase (OPH, EC 3.1.8.1) is a broad-spectrum phosphotriesterase that is capable of detoxifying a variety of organophosphorus neurotoxins by hydrolyzing various phosphorus-ester bonds (P-O, P-F, P-CN, and P-S) between the phosphorus center and an electrophilic leaving group. OPH is capable of hydrolyzing the P-X bond of various organophosphorus compounds at quite different catalytic rates: P-O bonds (kcat = 67-5000 s-1), P-F bonds (kcat = 0.01-500 s-1), and P-S bonds (kcat = 0.0067 to 167 s-1). P-S bond cleavage was readily demonstrated and characterized in these studies by quantifying the released free thiol groups using 5,5'-dithio-bis-2-nitrobenzoic acid or by monitoring an upfield shift of approximately 31 ppm by 31P NMR. A decrease in the toxicity of hydrolyzed products was demonstrated by directly quantifying the loss of inhibition of acetylcholinesterase activity. Phosphorothiolate esters, such as demeton-S, provided noncompetitive inhibition for paraoxon (a P-O triester) hydrolysis, suggesting that the binding of these two different classes of substrates was not identical.
Topics: Aryldialkylphosphatase; Azinphosmethyl; Binding Sites; Biodegradation, Environmental; Disulfoton; Environmental Pollutants; Esterases; Flavobacterium; Hydrolysis; Insecticides; Kinetics; Malathion; Molecular Structure; Organothiophosphorus Compounds; Paraoxon; Phosphoramides; Pseudomonas; Recombinant Proteins; Substrate Specificity
PubMed: 7726573
DOI: 10.1006/abbi.1995.1204 -
Journal of Chromatography. A May 2000The stability of nine organophosphorus insecticides (azinphos-ethyl, azinphos-methyl, diazinon, EPN, ethion, fonofos, malathion, phosmet and parathion-methyl) was...
The stability of nine organophosphorus insecticides (azinphos-ethyl, azinphos-methyl, diazinon, EPN, ethion, fonofos, malathion, phosmet and parathion-methyl) was evaluated under a variety of storage conditions. Large volumes of surface water (4 l) were extracted using large-particle-size graphitized carbon black cartridges (Carbopack B 60-80 mesh). The effects of temperature, matrix type and drying of cartridges on the recovery of these contaminants, after different storage periods, were studied and compared to the conservation of surface water in bottles. After a 2-month period, all the chemicals stored on cartridges and kept at -20 degrees C remained stable, with recoveries ranging from 70 to 134%. By contrast, phosmet and EPN could no longer be recovered from the bottled surface water. Cartridges kept at -20 degrees C fared better than did those stored at 4 degrees C and 20 degrees C. The type of matrix water selected appears to have kept the target pesticides stored on cartridges from degrading, compared to the Milli-Q water, in which malathion and phosmet were unstable. The effect of the cartridges being either wet or dry made no difference in terms of improving the recovery of chemicals. After immediate surface water extraction, the most practical storage condition for the target insecticides was found to be storage on cartridges in the dark at -20 degrees C, with no drying or solvent washing of the Carbopack B material.
Topics: Carbon; Insecticides; Organophosphorus Compounds; Reference Standards; Water Pollutants, Chemical
PubMed: 10870696
DOI: 10.1016/s0021-9673(00)00169-2 -
Toxicology and Applied Pharmacology Sep 2001Ethylazinphos increases the passive proton permeability of lipid bilayers reconstituted with dipalmitoylphosphatidylcholine (DPPC) and mitochondrial lipids. A sharp...
Ethylazinphos increases the passive proton permeability of lipid bilayers reconstituted with dipalmitoylphosphatidylcholine (DPPC) and mitochondrial lipids. A sharp increase of proton permeability is detected at insecticide/lipid molar ratios identical to those inducing phase separation in the plane of DPPC bilayers, as revealed by differential scanning calorimetry (DSC). Ethylazinphos progressively depresses the transmembrane potential (DeltaPsi) of mitochondria supported by piruvate/malate, succinate, or ascorbate/TMPD. Additionally, a decreased depolarization induced by ADP depends on ethylazinphos concentration, reflecting a phosphorylation depression. This loss of phosphorylation is a consequence of a decreased DeltaPsi. A decreased respiratory control ratio is also observed, since ethylazinphos stimulates state 4 respiration and inhibits ADP-stimulated respiration (state 3). Ethylazinphos concentrations up to 100 nmol/mg mitochondrial protein increase the rate of state 4 together with a decrease in DeltaPsi, without significant perturbation of state 3 and carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP)-uncoupled respiration. For increased insecticide concentrations, the state 3 and FCCP-uncoupled respiration are inhibited to approximately the same extent. The perturbations are more pronounced when the energization is supported by pyruvate/malate and less effective when succinate is used as substrate. The present data, in association with previous DSC studies, indicate that ethylazinphos, at concentrations up to 100 nmol/mg mitochondrial protein, interacts with the lipid bilayer of mitochondrial membrane, changing the lipid organization and increasing the proton permeability of the inner membrane. The increased proton permeability explains the decreased oxidative phosphorylation coupling. Resulting disturbed ATP synthesis may significantly underlie the mechanisms of ethylazinphos toxicity, since most of cell energy in eukaryotes is provided by mitochondria.
Topics: Animals; Azinphosmethyl; Calorimetry, Differential Scanning; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; Cytoplasmic Vesicles; Dose-Response Relationship, Drug; Female; Insecticides; Intracellular Membranes; Male; Membrane Lipids; Membrane Potentials; Mitochondria, Liver; Oxidative Phosphorylation; Permeability; Protons; Rats; Rats, Sprague-Dawley
PubMed: 11559019
DOI: 10.1006/taap.2001.9246 -
Hua Xi Yi Ke Da Xue Xue Bao = Journal... Mar 1993A total of 22 organophosphorus pesticides (OPPs), including 8 ethyl-, 9 methyl-, and 5 other OPPs, were tested for mutagenicity in micronucleus assay system both in 615...
A total of 22 organophosphorus pesticides (OPPs), including 8 ethyl-, 9 methyl-, and 5 other OPPs, were tested for mutagenicity in micronucleus assay system both in 615 mouse marrow cells in vivo with multi-intraperitoneal administrations and in cultured Chinese hamster lung (CHL) cells in vitro; and structure-mutagenicity relationship of OPPs was analyzed. Among the OPPs tested in vivo, 5 ethyl-(diazinon, chlorpyrifos, disulfoton, ethion, and parathion), and only 1 methyl-(dimethoate) were found mutagenic, while the other OPPs were negative. Six ethyl- (azinphos ethyl, chlorpyrifos, ethion, parathion, phosaione, and quinaphos), 8 methyl- (azinophos methyl, chlorpyrifos methyl, dichlorvos, dimethoate, fenitrothion, malathion, parathion methyl, and trimethyl phosphate), and 2 other OPPs (EII and MIA), however, induced micronucleus in CHL cells in vitro. The results indicated that most of the ethyl-OPPs tested showed the ability to induce micronucleus both in vivo and in vitro, and that most of the methyl-OPPs were positive only in vitro. The mechanism for the adversity of mutagenic activity in micronucleus assay in vivo and in vitro produced by different kinds of OPPs was also discussed.
Topics: Animals; Bone Marrow Cells; Cells, Cultured; Cricetinae; Cricetulus; Female; Fibroblasts; Insecticides; Lung; Male; Mice; Micronucleus Tests; Mutagenesis; Organophosphorus Compounds
PubMed: 8340099
DOI: No ID Found -
Analytical Biochemistry Jan 1992A flow injection system, incorporating an acetylcholinesterase (AChE) single bead string reactor (SBSR), for the determination of some organophosphorous (azinphos-ethyl,...
A flow injection system, incorporating an acetylcholinesterase (AChE) single bead string reactor (SBSR), for the determination of some organophosphorous (azinphos-ethyl, azinphos-methyl, bromophos-methyl, dichlorovos, fenitrothion, malathion, paraoxon, parathion-ethyl and parathion-methyl) and carbamate insecticides (carbofuran and carbaryl) is presented. The detector is a simple pH electrode with a wall-jet entry. Variations in enzyme activity due to inhibition are measured from pH changes when the substrate (acetylcholine) is injected before and after the passage of the solution containing the insecticide. The percentage inhibition of enzyme activity is correlated to the insecticide concentration. Several parameters influencing the performance of the system are studied and discussed. The detection limits of the insecticides ranged from 0.5 to 275 ppb. The determination of these compounds was conducted in Hepes buffer and a synthetic sea water preparation. The enzyme reactor can be regenerated after inhibition with a dilute solution of 2-PAM and be reused for analysis. The immobilized enzyme did not lose any activity up to 12 weeks when stored at 4 degrees C.
Topics: Acetylcholine; Acetylcholinesterase; Carbamates; Cholinesterase Inhibitors; Enzyme Activation; Enzymes, Immobilized; Flow Injection Analysis; Hydrogen-Ion Concentration; Hydrolysis; Insecticides; Organophosphorus Compounds; Substrate Specificity; Temperature
PubMed: 1595894
DOI: 10.1016/0003-2697(92)90297-k -
Chemistry and Physics of Lipids Feb 1999Perturbations induced by ethylazinphos on the physical organization of dipalmitoylphosphatidylcholine (DPPC) and DPPC/cholesterol membranes were studied by differential...
Perturbations induced by ethylazinphos on the physical organization of dipalmitoylphosphatidylcholine (DPPC) and DPPC/cholesterol membranes were studied by differential scanning calorimetry (DSC) and fluorescence polarization of 2-, 6-, 12-(9-anthroyloxy) stearic acids and 16-(9-anthroyloxy) palmitic acid. Ethylazinphos (50 and 100 microM) increases the fluorescence polarization of the probes, either in the gel or in the fluid phase of DPPC bilayers, and this concentration dependent effect decreases from the surface to the bilayer core. Additionally, the insecticide displaces the phase transition to a lower temperature range and broadens the transition profile of DPPC. A shifting and broadening of the phase transition is also observed by DSC. Furthermore at insecticide/lipid molar ratios higher than 1/7, DSC thermograms, in addition to the normal transition centered at 41 degrees C, also display a new phase transition centered at 45.5 degrees C. The enthalpy of this new transition increases with insecticide concentration, with a corresponding decrease of the main transition enthalpy. Ethylazinphos in DPPC bilayers with low cholesterol (< or = 20 mol%) perturbs the membrane organization as described above for pure DPPC. However, cholesterol concentrations higher than 20 mol% prevent insecticide interaction, as revealed by fluorescence polarization and DSC data. Apparently, cholesterol significantly modulates insecticide interaction by competition for similar distribution domains in the membrane. The present results strongly support our previous hypothesis that ethylazinphos locates in the cooperativity region, i.e. the region of C1-C9 atoms of the acyl chains, and extends to the lipid-water interface, where it increases lipid packing order sensed across all the thickness of the bilayer. Additionally, and, on the basis of DSC data, a lateral regionalization of ethylazinphos is here tentatively suggested.
Topics: 1,2-Dipalmitoylphosphatidylcholine; Azinphosmethyl; Calorimetry, Differential Scanning; Cholesterol; Fluorescence Polarization; Fluorescent Dyes; In Vitro Techniques; Insecticides; Lipid Bilayers; Membrane Lipids; Palmitic Acids; Stearic Acids
PubMed: 10192930
DOI: 10.1016/s0009-3084(98)00105-4