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Mikrochimica Acta May 2020A sensitive and readily deployable analytical method has been reported for the simultaneous analysis of pirimicarb (PRM) and fenitrothion (FEN) pesticide residues in...
A sensitive and readily deployable analytical method has been reported for the simultaneous analysis of pirimicarb (PRM) and fenitrothion (FEN) pesticide residues in environmental water samples using fabric phase sorptive extraction (FPSE) followed by high-performance liquid chromatography combined with photodiode array (HPLC-PDA) detector. Both pesticides were successfully determined with a Luna omega C18 column under isocratic elution mode by means of acetonitrile and phosphate buffer (pH 3.0) as the mobile phase. The quantitative data for PRM and FEN were obtained at their maximum wavelengths of 310 nm and 268 nm, respectively. The calibration plots were linear in the range 10.00-750.00 ng mL and 10.00-900.00 ng mL with correlation coefficient of 0.9984 and 0.9992 for PRM and FEN, respectively. Major FPSE experimental variables were investigated in detail, such as contact time with the FPSE membrane, pH and electrolyte concentration, and the volume and type of desorption solvent. Under the optimized conditions, the developed method showed satisfactory reproducibility with relative standard deviations less than 2.5% and low limits of detection of 2.98 and 3.02 ng mL for PRM and FEN, respectively. The combined procedure allows for enhancement factors ranging from 88 to 113, with pre-concentration values of 125 for both analytes. The chromatographic resolutions were approx. 12 for FEN (retention factor of 3.52) and PRM (retention factor of 6.09), respectively, with a selectivity factor of 1.73. Finally, the validated method was successfully applied to real environmental water samples for the determination of these pesticides. Graphical abstract.
Topics: Carbamates; Cellulose; Chromatography, High Pressure Liquid; Dimethylpolysiloxanes; Fenitrothion; Lakes; Limit of Detection; Pesticide Residues; Polyesters; Ponds; Pyrimidines; Reproducibility of Results; Rivers; Solid Phase Extraction; Textiles; Water Pollutants, Chemical
PubMed: 32430628
DOI: 10.1007/s00604-020-04306-7 -
Journal of Agricultural and Food... Apr 2020The goal of this study was to perform in silico identification of bioinsecticidal potential of 42 monoterpenes against and Snyder. Quantitative structure-activity...
The goal of this study was to perform in silico identification of bioinsecticidal potential of 42 monoterpenes against and Snyder. Quantitative structure-activity relationship (QSAR) modeling was performed for both organisms, while docking and molecular dynamics were used only for . Neryl acetate has the lowest interaction energy (-87 kcal/mol) against active site of acetylcholinesterase, which is comparable to the ones of methiocarb and pirimicarb (-90 kcal/mol) and reported PDB binder 9-(3-iodobenzylamino)-1,2,3,4-tetrahydroacridine (-112.67 kcal/mol). Interaction stability was verified by molecular dynamics simulations and showed that the stability of ACHE active site complexes with three selected terpenes is comparable to the one of the pirimicarb and methiocarb. Overall, our results suggest that pulegone, citronellal, carvacrol, linalyl acetate, neryl acetate, citronellyl acetate, and geranyl acetate may be considered as a potential pesticide candidates.
Topics: Acetylcholinesterase; Animals; Drosophila melanogaster; Insect Proteins; Insecticides; Isoptera; Molecular Docking Simulation; Molecular Dynamics Simulation; Monoterpenes; Quantitative Structure-Activity Relationship
PubMed: 32251592
DOI: 10.1021/acs.jafc.0c00272 -
Journal of Environmental Science and... 2020We evaluated the real effects of pollutants through a multi-generation study. We tested whether short-term exposure (48 h) of successive (first and second) generations...
We evaluated the real effects of pollutants through a multi-generation study. We tested whether short-term exposure (48 h) of successive (first and second) generations of neonates (<24-h-old) to two acetylcholinesterase inhibitor insecticides, pyraclofos, and pirimicarb, would change insecticide sensitivity and life-cycle parameters over four generations. Additionally, we tested whether acetylcholinesterase (AChE) activity levels would be associated with this sensitivity change. Sensitivities (48 h EC value, using immobility as the endpoint) in chironomids (<24-h-old) and insect life-cycle parameters (the number of larvae per egg mass and adult size) were investigated. Parental chironomids produced larvae that were less sensitive than those in the control group following the two 48 h pirimicarb exposure events, whereas exposure to pyraclofos did not affect sensitivity. The AChE activity in larvae with low sensitivity to pirimicarb was significantly higher than that in the control. Thus, increased AChE activity might be associated with low sensitivity. The life-cycle parameters in chironomids recovered from the effects of pyraclofos and pirimicarb suggested they could adapt to the insecticides by changing biomass allocation. Our study suggested potential chemical risks of insecticide stress and how aquatic organisms adapt to it.
Topics: Adaptation, Biological; Animals; Carbamates; Chironomidae; Cholinesterase Inhibitors; Ecotoxicology; Insecticides; Larva; Organothiophosphates; Pyrimidines; Water Pollutants, Chemical
PubMed: 32065017
DOI: 10.1080/03601234.2019.1708165 -
Journal of Economic Entomology Dec 2019The green peach aphid, Myzus persicae (Sulzer), is one of the most common pest species that has the potential to transmit more than 100 plant viruses. Controlling this...
The green peach aphid, Myzus persicae (Sulzer), is one of the most common pest species that has the potential to transmit more than 100 plant viruses. Controlling this pest is difficult because it has become resistant to a wide range of insecticides. Nanoformulation has the capacity to reduce the pesticide load in agriculture and thus reduce the risks on human health and the environment. In this study, nanocapsules of pirimicarb and pymetrozine were prepared using nanostructured lipid carriers. The size, morphology, and encapsulation efficiency of nanocapsules were investigated using dynamic light scattering, scanning electron microscopy, and UV-VIS spectrophotometer. Zeta potential studies revealed stability of the nanocapsules of both insecticides. The encapsulation efficiencies were 85 and 81% for pirimicarb and pymetrozine, respectively. The nanocapsules were spherical with sizes of 35.38 and 35.12 nm for pirimicarb and pymetrozine, respectively. The LC50 values for the wettable powder (WP) and nanocapsule of pirimicarb after 48 h were 216.2 and 73.2 mg ai/l; for pymetrozine after 96 h, the values were 40.6 and 14.8 mg ai/l, respectively. Durations of residual activity for WP and nanocapsule formulations of pirimicarb were 7 and 15 d, respectively. The residual activity periods for WP and nanocapsule formulations of pymetrozine were 9 and 17 d, respectively. The results revealed that nanoencapsulation can improve performance allowing for reduced doses and increased duration of insecticidal activity for both of the insecticides tested.
Topics: Animals; Aphids; Carbamates; Insecticides; Nanocapsules; Pyrimidines; Triazines
PubMed: 31365743
DOI: 10.1093/jee/toz203 -
Food Chemistry Nov 2019Matrix effects in complex tea matrices remains a great challenge to rapid quantitative analysis of multi-residue pesticides by analysis of mass spectrometry. Herein, a...
Matrix effects in complex tea matrices remains a great challenge to rapid quantitative analysis of multi-residue pesticides by analysis of mass spectrometry. Herein, a mixed-mode polymer cationic exchange based dispersive solid-phase extraction (DSPE) procedure was established to eliminate matrix effects of tea for a rapid target alkaline multi-residue pesticides analysis. One-step DSPE procedure can eliminate matrix interferences from the tea extract without additional dilution or tedious cleanup operations. Liquid chromatography-high resolution mass spectrometry using pre-column dilution injection mode was used as the detection technique, while eliminating solvent effects of target analytes and improving the detection sensitivity. Based on this effective analytical method, the results of absolute matrix effects were within 0.77-1.08 for quantitation of the 68 alkaline pesticides, and superior relative matrix effects were also achieved with RSD values below 9.8%. Finally, this method was validated and applied to the alkaline pesticides analysis of the 123 tea samples.
Topics: Caffeine; Chromatography, Liquid; Food Analysis; Food Contamination; Mass Spectrometry; Pesticide Residues; Polyphenols; Reproducibility of Results; Solid Phase Extraction; Tea
PubMed: 31302427
DOI: 10.1016/j.foodchem.2019.125146 -
Journal of Mass Spectrometry : JMS Feb 2020Detection of pesticide residues in food samples is important for safeguarding food quality and safety. Conventional approaches for detection of pesticides in food...
Detection of pesticide residues in food samples is important for safeguarding food quality and safety. Conventional approaches for detection of pesticides in food samples typically involve labour-intensive and time-consuming sample pretreatment and chromatographic separation. In this study, solid phase micro-extraction fibres were used to rapidly extract and enrich pesticides in honey, a popular agricultural product with complex matrix, and then directly coupled with electrospray ionization mass spectrometry for qualitative and quantitative analysis. Three pesticides, ie, atrazine, benalaxyl, and pirimicarb, were investigated using the technique and their analytical performances were evaluated. The limits of detection and limits of quantitation of all the three pesticides could fulfil the cut-off values of the international standard. Linear calibration curves were constructed with good R coefficients, and the accuracy and precision were in acceptable ranges for all the pesticides. The analysis time is much reduced, with only minimum sample preparation and no chromatographic separation involved. The technique is simple and easy to set up, and can be extended for analysis of other analytes and sample systems.
Topics: Honey; Limit of Detection; Linear Models; Pesticide Residues; Reproducibility of Results; Solid Phase Microextraction; Spectrometry, Mass, Electrospray Ionization
PubMed: 31183930
DOI: 10.1002/jms.4380 -
Journal of Molecular Recognition : JMR Sep 2019This study aimed to prepare a novel quartz crystal microbalance (QCM) sensor for the detection of pirimicarb. Pirimicarb-imprinted poly (ethylene glycol...
This study aimed to prepare a novel quartz crystal microbalance (QCM) sensor for the detection of pirimicarb. Pirimicarb-imprinted poly (ethylene glycol dimethacrylate-N-metacryloyl-(l)-tryptophan methyl ester) [p (EGDMA-MATrp)] nanofilm (MIP) on the gold surface of a QCM chip was synthesized using the molecular imprinting technique. A nonimprinted p (EGDMA-MATrp) nanofilm (NIP) was also synthesized using the same experimental technique. The MIP and NIP nanofilms were characterized via Fourier transform infrared spectroscopy attenuated total reflectance spectroscopy, contact angle, atomic force microscopy, and an ellipsometer. A competitive adsorption experiment on the sensor was performed to display the selectivity of the nanofilm. An analysis of the QCM sensor showed that the MIP nanofilm exhibited high sensitivity and selectivity for pirimicarb determination. A liquid chromatography-tandem mass spectrometry method was prepared and validated to determine the accuracy and precision of the QCM sensor. The accuracy and precision of both methods were determined by a comparison of six replicates at three different concentrations to tomato samples extracted by using a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method. The limit of detection of the QCM sensor was found to be 0.028 nM. In conclusion, the QCM sensor showed good accuracy, with recovery percentages between 91 and 94%. Also, the pirimicarb-imprinted QCM sensor exhibited a fast response time, reusability, high selectivity and sensitivity, and a low limit of detection. Therefore, it offers a serious alternative to the traditional analytical methods for pesticide detection in both natural sources and aqueous solutions.
Topics: Carbamates; Limit of Detection; Solanum lycopersicum; Molecular Imprinting; Nanoparticles; Polymers; Pyrimidines; Quartz Crystal Microbalance Techniques; Reproducibility of Results
PubMed: 31033053
DOI: 10.1002/jmr.2785 -
Environmental Science and Pollution... Jun 2019Insecticide spray in fruit gardens is a very common practice in different districts of Pakistan. These toxic sprays not only deteriorate the taste of fruit but also due...
Insecticide spray in fruit gardens is a very common practice in different districts of Pakistan. These toxic sprays not only deteriorate the taste of fruit but also due to wet deposition travel through soil, they reach groundwater via leaching process. In the present study, imidazolium-based ionic liquid ([Cim][CHNH]Br) and its cellulose acetate-supported membrane ([CA-Cim][CHNH]Br) was prepared and characterized using FTIR, XRD, and SEM. These materials are used as adsorbents for the removal of "Pirimicarb" (an insecticide from waste water). A closed batch at varying parameters, i.e., concentration and temperature as function of time, was conducted on UV-Vis spectrophotometer. Comparison of removal capacity exposed better (74%) adsorption trend by CA-IL membrane than ionic liquid (68%). Thermodynamic studies projected spontaneous process (-ΔG), favoring endothermic reaction (ΔH, ΔS). Kinetics supported pseudo-second order reaction while fitness of isothermic models (Langmuir, Freundlich, Temkin) proposed multistep intraparticle diffusion process.
Topics: Adsorption; Carbamates; Cellulose; Ionic Liquids; Ions; Kinetics; Pakistan; Pyrimidines; Temperature; Thermodynamics; Wastewater; Water Pollutants, Chemical
PubMed: 30980372
DOI: 10.1007/s11356-019-04681-6 -
Food and Chemical Toxicology : An... Jan 2019Dietary supplements are regulated by the U.S. FDA as a subset of foods. Most botanical dietary ingredients do not have pesticide tolerances, resulting in the enforcement...
Dietary supplements are regulated by the U.S. FDA as a subset of foods. Most botanical dietary ingredients do not have pesticide tolerances, resulting in the enforcement of zero tolerance or general maximum residue limits (GMRL), rather than utilizing science-informed tolerances. In the current study, chemical-specific maximum allowable levels (MALs) were derived for 185 pesticides by converting existing, authoritative-body human health effects criteria. MALs were derived for 96% of pesticides using criteria established by the U.S. EPA. If multiple authoritative-bodies had established human health effects criteria, the most scientifically-defensible criteria was selected, taking into consideration both carcinogenic and non-carcinogenic endpoints. Five pesticides (o-phenylphenol, pirimicarb, oxadixyl, tetradifon, o,p'-DDT), lacking criteria established by the U.S. EPA had criteria established by other authoritative-bodies that were utilized in the derivation of MALs. Two pesticides did not have any established human health effects criteria (o,p'-DDD and o,p'-DDE). In total, MALs were derived from existing criteria for over 98% of the pesticides in the present study. Consequently, it is demonstrated that human health effects criteria derived by authoritative-bodies can be effectively utilized to derive chemical-specific, science-informed MALs applicable to all food commodities, including botanical ingredients, thereby, minimizing reliance on precautionary zero tolerance and GMRLs.
Topics: Dietary Supplements; Drug Contamination; Humans; Maximum Allowable Concentration; Pesticide Residues
PubMed: 30468839
DOI: 10.1016/j.fct.2018.11.045 -
The Science of the Total Environment Feb 2019In arid and semi-arid areas the use of treated wastewater for crop irrigation and other agricultural practices, such as the use of pesticides, increase the number of...
In arid and semi-arid areas the use of treated wastewater for crop irrigation and other agricultural practices, such as the use of pesticides, increase the number of emerging contaminants (ECs) in crops. Hazards of these practices to human being are largely unknown since there are few studies yet covering a short range of compounds and most of them under non-realistic conditions. This study aims at assessing this problem that will become global soon in an area of Saudi Arabia heavily affected by the reuse of treated wastewater and pesticide in order to ascertain its scale. The novelty of the study relays in the large number of ECs covered and the variety of crops (cabbage, barley, green beans, eggplants, chili, tomato and zucchini) analysed. Extraction procedure developed provided an appropriate extraction yield (up to 50% of the compounds were recovered within a 70-120% range), with good repeatability (relative standard deviations below 20% in most cases) and sensitivity (LOQ < 25 ng g) for the model compounds. Determination by liquid chromatography quadrupole time-of-flight (LC-QqTOF-MS) is able to identify >2000 contaminants. Sixty-four ECs were identified in wastewater but of the sixty-four compounds, six pharmaceuticals (atenolol, caffeine, carbamazepine and its metabolites 10,11-epoxycarbamazepine, gemfibrozil, and naproxen) and seven pesticides (acetamiprid, atrazine deethyl, azoxystrobin, bupirimate, diazinon, malathion, pirimicarb and some of their metabolites) were detected in plants. Furhermore, one metabolite of the ibuprofen (not detected in water or soil), the ibuprofen hexoside was also found in plants. Up to our knowledge, this study demonstrate for the first time the accumulation of ECs in crops irrigated with treated wastewater under real non-controlled environmental conditions.
Topics: Agricultural Irrigation; Crops, Agricultural; Environmental Monitoring; Saudi Arabia; Soil; Soil Pollutants; Waste Disposal, Fluid; Wastewater; Water Pollutants, Chemical
PubMed: 30368185
DOI: 10.1016/j.scitotenv.2018.10.224