Abstract:The determination of 15 pyrethroids in soil and water samples was carried out by gas chromatography with mass spectrometry. Compounds were extracted from the soil samples (4 g) using solid-liquid extraction and then salting-out assisted liquid-liquid extraction. The acetonitrile phase obtained (0.8 mL) was used as a dispersant solvent, to which 75 μL of chloroform was added as an extractant solvent, submitting the mixture to dispersive liquid-liquid microextraction. For the analysis of water samples (40 mL), m… Show more
“…The extraction efficiency remained relatively steady with the sample pH increasing to 11. Based on published literatures, the sample pH was set at 7 in further experiment.…”
In this work, 1‐vinyl‐3‐butylimidazolium bis((trifluoromethyl) sulfonyl)imide modified Fe3O4 magnetic nanoparticles were prepared by “thiol‐ene” click chemistry. The morphology, composition, and structure of as prepared functional material was investigated with several technique. Such magnetic material was applied to magnetic solid‐phase extraction of pyrethroid pesticides, and the analytes were quantitatively analyzed by gas chromatography‐mass spectrometry. Significant parameters of proposed method, including adsorbents amount, vortexing time, solution pH, and eluent volume and type, were optimized. Under the optimized condition, this method exhibited good linearity in the range of 0.19–200 μg L−1 for resmethrin, 0.44–200 μg L−1 for bifenthrin, 0.35–200 μg L−1 for fenpropathrin, and 0.31–200 μg L−1 for cyhalothrin, with the correlation coefficients>0.9992, and low limits of detection (0.06–0.13 μg L−1, S/N=3). The method was successfully applied to quantitative determination of pyrethroid pesticides in environmental water sample with the satisfactory recovery ranging from 85.7 % to 110.4 % and relative standard deviations ranging from 1.3 % to 6.6 %. The results indicated that the proposed magnetic solid‐phase extraction is a simple, efficient and time‐saving method.
“…The extraction efficiency remained relatively steady with the sample pH increasing to 11. Based on published literatures, the sample pH was set at 7 in further experiment.…”
In this work, 1‐vinyl‐3‐butylimidazolium bis((trifluoromethyl) sulfonyl)imide modified Fe3O4 magnetic nanoparticles were prepared by “thiol‐ene” click chemistry. The morphology, composition, and structure of as prepared functional material was investigated with several technique. Such magnetic material was applied to magnetic solid‐phase extraction of pyrethroid pesticides, and the analytes were quantitatively analyzed by gas chromatography‐mass spectrometry. Significant parameters of proposed method, including adsorbents amount, vortexing time, solution pH, and eluent volume and type, were optimized. Under the optimized condition, this method exhibited good linearity in the range of 0.19–200 μg L−1 for resmethrin, 0.44–200 μg L−1 for bifenthrin, 0.35–200 μg L−1 for fenpropathrin, and 0.31–200 μg L−1 for cyhalothrin, with the correlation coefficients>0.9992, and low limits of detection (0.06–0.13 μg L−1, S/N=3). The method was successfully applied to quantitative determination of pyrethroid pesticides in environmental water sample with the satisfactory recovery ranging from 85.7 % to 110.4 % and relative standard deviations ranging from 1.3 % to 6.6 %. The results indicated that the proposed magnetic solid‐phase extraction is a simple, efficient and time‐saving method.
“…Sample pretreatment processes take an important role in the analytical procedure. The classic sample preparation methods (i.e., LLE and SPE) have been widely developed for extraction and cleanup in the residue analysis . However, the classic sample preparation method consumes a large amount of toxic and expensive organic solvents (i.e., LLE), wastes time and has an insufficient sensitivity .…”
In this study, a simple and accurate sample preparation method based on dispersive solid‐phase extraction and dispersive liquid‐liquid microextraction has been developed for the determination of seven novel succinate dehydrogenase inhibitor fungicides (isopyrazam, fluopyram, pydiflumetofen, boscalid, penthiopyrad, fluxapyroxad, and thifluzamide) in watermelon. The watermelon samples were extracted with acetonitrile, cleaned up by dispersive solid‐phase extraction procedure using primary secondary amine, extracted and concentrated by the dispersive liquid‐liquid microextraction procedure with 1,1,2,2‐tetrachloroethane, and then analyzed by ultra high performance liquid chromatography with tandem mass spectrometry. The main experimental factors affecting the performance of dispersive solid‐phase extraction and dispersive liquid‐liquid microextraction procedure on extraction efficiency were investigated. The proposed method had a good linearity in the range of 0.1–100 µg/kg with correlation coefficients (r) of 0.9979–0.9999. The limit of quantification of seven fungicides was 0.1 µg/kg in the method. The fortified recoveries of seven succinate dehydrogenase inhibitor fungicides at three levels ranged from 72.0 to 111.6% with relative standard deviations of 3.4–14.1% (n = 5). The proposed method was successfully used for the rapid determination of seven succinate dehydrogenase inhibitor fungicides in watermelon.
“…However, the concentrations of analytes are very low and the sensitivity of direct detection is often inadequate in complex matrix. Some sample pretreatment technologies including SPE and liquid-liquid microextraction have been combined with the modern instrument to obtain better analysis results [2,6,[13][14][15][16][17][18]. Different pretreatment technologies have greatly improved the analytical ability.…”
Magnetic CoFe O -embedded porous graphitic carbon nanocomposites were prepared through a facile solid-phase thermal reaction with NaCl as a template. The material was applied in the magnetic solid-phase extraction process coupled with high performance liquid chromatography with a diode array detector to detect the trace fenpropathrin, cyhalothrin, S-fenvalerate, and bifenthrin in different water samples. The synthesis conditions of nanomaterial including glucose concentration and calcination time on extraction performance for pyrethroid pesticides have been investigated. Different magnetic solid-phase extraction parameters have been studied, such as the nanomaterial amount, solution pH, eluent types, adsorption time, and the reusability. Under the optimum conditions, good recoveries (80.2-110.9%) were achieved with relative standard deviations of 0.2-5.8%. There are probably hydrophobic interactions and dipole-dipole attractions between nanocomposites and the analytes.
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