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In this study, a novel enhanced dispersive liquid–liquid microextraction method was developed for the determination of four pyrethroid insecticides (deltamethrin, etofenprox, bifenthrin and fenpropathrin) in tea infusions, based on solidified floating organic solvents containing [P4,4,4,12][PF6] generated in situ and a hydrophobic mixture of 1-chlorododecane and 1-dodecanol. Both the hydrophobic mixture and [P4,4,4,12][PF6] were used as extractants in this method. Several key factors, such as the solvent mixture dosage, the molar ratio of [P4,4,4,12]Br to KPF6, the reaction temperature and the added salt concentration, that affected the recovery were optimized. According to the results of spiked recovery experiments under optimized conditions, the recoveries of all four pyrethroid pesticides ranged from 81.2% to 103.7%, with relative standard deviation (RSD) values ranging from 2.2% to 5.1%. The limit of detection (LOD) values for deltamethrin, etofenprox, bifenthrin and fenpropathrin were 0.39 μg L−1, 0.47 μg L−1, 0.42 μg L−1 and 0.68 μg L−1, respectively. This method fully utilizes the advantageous characteristics of ionic liquids (ILs) and adds the extractant mixture simultaneously to the IL, making the whole experimental process environmentally friendly, efficient, simple and fast. Overall, this is an effective method for the detection of pyrethroid pesticide residues in tea infusions. [ABSTRACT FROM AUTHOR]

In this study, a novel sorbent, 1-octyl-3-methylimidazolium hexafluorophosphate functionalised magnetic poly β-cyclodextrin, was successfully synthesised and applied to magnetic solid-phase extraction for the determination of pyrethroids in tea infusions. The sorbent was characterised by transmission electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometer and Brunauer–Emmett–Teller measurement. All factors affecting extraction efficiency, such as sorbent amount, extraction time, ionic strength and desorption conditions, were optimised individually. Under the chosen conditions, wide linearity (2.5–500 μg L−1) with determination coefficients ranging from 0.9995 to 0.9999, low limits of detection of 0.32–0.54 μg L−1 and good precision (intra-day: 2.6–7.0%; inter-day: 3.5–7.6%) were achieved for four pyrethroids in tea infusions. The relative recoveries of target analytes in real tea infusion samples were from 70% to 101% with relative standard deviations lower than 9.1%. We conclude that the proposed method is promising in the detection of pyrethroids in tea infusions. [ABSTRACT FROM AUTHOR]

Magnetic hyperbranched polyamideamine was carboxylated using succinic anhydride and modified further with 1‐octyl‐3‐methylimidazole hexafluorophosphate successively. The morphology and chemical composition of the prepared material was characterized by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett‐Teller measurement, X‐ray photoelectron spectroscopy, etc. 1‐Octyl‐3‐methylimidazole hexafluorophosphate modified magnetic hyperbranched polyamideamine was used as sorbent in the magnetic solid‐phase extraction for the separation and enrichment of five pyrethroid insecticides from tea infusion. The magnetic solid‐phase extraction method proposed in this article has low method detection limits (0.53–0.71 ng/mL), acceptable coefficient of determination (0.9992–0.9998), wide linear ranges (2.5–500.0 ng/mL), and good repeatability (intraday: 1.2–6.3%; interday: 1.6–5.4%). In the detection of five pyrethroid insecticides in tea infusion, relative recoveries were in the range from 87.7 to 114.7% with satisfactory relative standard deviations (0.2–7.4%). With the aid of quantum chemistry calculations, the interaction energy between the sorbent and five pyrethroid insecticides was calculated, which proved the necessity of the modification of 1‐octyl‐3‐methylimidazole hexafluorophosphate. [ABSTRACT FROM AUTHOR]

In this work, a novel extraction technique based on the effervescence‐assisted dispersion and magnetic recovery of attapulgite/polypyrrole sorbents was developed for determining the concentrations of five pyrethroids in honey samples. The magnetic nanoparticles were synthesized by a one‐pot method. Several experimental parameters that affected the extraction efficiency, including the dispersion conditions, pH, ionic strength, and desorption conditions, were investigated. Under optimal conditions, the calibration curves for the five pyrethroids in honey samples exhibited good linearity, with r2 values ranging from 0.9979 to 0.9990. The limits of detection varied between 0.21 and 0.34 µg/L. Satisfactory recoveries of 81.42–106.73% with intra‐ and interday relative standard deviations of less than 6.94 and 10.89%, respectively, were obtained. Moreover, the sorbents exhibited acceptable batch‐to‐batch repeatability in the range of 5.06–15.01%, and each sorbent could be reused for up to four extraction cycles without a significant loss in the extraction recovery. [ABSTRACT FROM AUTHOR]

A novel dispersive magnetic solid phase microextraction method based on ionic liquid-coated and cyclodextrin-functionalized magnetic core dendrimer nanocomposites has been developed for the determination of pyrethroids in juice samples. The different generation magnetic core dendrimer nanocomposites were successfully synthesized and the nanocomposites possess both the selective retention of guest dendrimer and cyclodextrin molecules and high adsorption capacities of ionic liquids. The extraction efficiencies of different generation magnetic core dendrimer nanocomposites were compared, and the type of nanocomposite with the highest recovery was obtained. Under the optimized experimental conditions, the method showed good linearity in the range of 3.5–500 μg L −1 . The LODs and LOQs were in the ranges of 0.36–1.3 μg L −1 and 1.2–4.3 μg L −1 , respectively. The method also showed acceptable accuracies ranging from 98.2% to 99.4%. The proposed method was demonstrated to broaden the potential applications of dendrimer for the detection of pyrethroid residues in various juice samples. [ABSTRACT FROM AUTHOR]

A novel membrane emulsification-assisted liquid–liquid microextraction method based on the solidification of floating organic drops was used to detect four pyrethroid pesticides (deltamethrin, etofenprox, fenpropathrin, and bifenthrin). In this method, [P 44412 ]Br was used as a surfactant that could be removed from water via the addition of KPF 6 . The extraction solvent was separated after centrifugation and solidification on the water surface. The parameters affecting the recovery of the target compounds, including the surfactant amount, [P 44412 ]Br-to-KPF 6 molar ratio, addition of salt, extraction solvent volume, and temperature, were individually optimized and further analyzed through an orthogonal array design (OAD) experiment. The optimized conditions were based on the results of the OAD experiment and single-factor analysis. Using these experimental conditions, the recovery of the four pyrethroids ranged from 91.3% to 98.1% with relative standard deviation (RSD) values ranging from 1.7 to 2.2%. Good linearity was observed, with values from 0.9982 to 0.9997, and the linear range was between 1 and 500 μg/L (5–500 μg/L for fenpropathrin). The limit of detection (LOD) values based on a signal-to-noise ratio (S/N) of 3:1 were 0.37–0.75 μg/L. The enrichment factor ranged from 90 to 96. Therefore, this method is suitable for the determination of pyrethroid pesticides in environmental water samples. [ABSTRACT FROM AUTHOR]

In this study, a novel ionic liquid-type surfactant modified attapulgite named as 1-dodecyl-3-methylimidazolium bromide-attapulgite (C 12 MIM-ATP) is successfully prepared and applied in dispersive solid phase extraction (dSPE) for the fast determination of pyrethroid residues in tea drinks. The primary factors that influenced the extraction efficiency, including sorbent type, amount of sorbent, extraction time, desorption conditions, pH and ionic strength, are investigated. The optimized results reveal that the extraction and desorption equilibria are rapidly obtained within 1 min. Under the optimized conditions, good linearity (2–500 μg/L) is observed for four pyrethroids in tea drinks with determination coefficients (r 2 ) ranged from 0.9992 to 1.0000. The limits of detection (LODs) are 0.6 μg/L for all pesticides. Acceptable extraction recoveries of target analytes are found from 90.28 to 107.56% with relative standard deviations (RSDs) less than 8.30% in real tea drink samples. The batch-to-bath repeatability is evaluated by recovery test on five independent synthesized C 12 MIM-ATP sorbents. Satisfactory batch-to-batch repeatability is obtained with the recovery factors varied in 15%. A small matrix effect is observed using C 12 MIM-ATP as the sorbent for detection pyrethroids in tea drinks. [ABSTRACT FROM AUTHOR]

An on-site dispersive liquid liquid microextraction base on the solidification of switchable solvent has been developed as a simple, rapid and eco-friendly sample extraction method for the fast determination of pyrethroid insecticides in aqueous samples using high-performance liquid chromatography with ultraviolet detection. In this extraction method, medium-chain saturated fatty acids (n ≥ 10), which can rapidly solidify at low temperatures (<20 °C), were investigated as switchable hydrophilic solvents. The fatty acids were converted into the hydrophilic form by adding sodium hydroxide. Microdroplets of the fatty acids were generated when injected into an acidic sample that had been pretreated by the addition of sulfuric acid. The formed cloudy solution was cooled to a low temperature to turn the fatty acids into a solid, which was then separated by filtration, thus avoiding the time-consuming step of centrifugation. The microextraction process was performed in a 10 mL syringe and the pretreatment process could thus be finished in 5 min. No external energy resources were required in this method, which makes it a potential method for on-site extraction. The optimal experimental parameters were as follows: 350 μL of decanoic acid (1 mol/L) was used as the extraction solvent, 150 μL of sulfuric acid (2 mol/L) was used to decrease the pH of the samples, no salt was added, and the temperature of the samples was in the range of 20–40 °C. Finally, the sample was cooled in an ice bath for three minutes. Under these optimal conditions, good responses for four pyrethroid insecticides were obtained in the concentration ranges of 1–500 μg/L, with coefficients of determination greater than 0.9993. The recoveries of the four pyrethroid insecticides ranged from 84.7 to 95.3%, with relative standard deviations ranging from 1.6 to 4.6%. The limits of detection based on a signal-to-noise ratio of 3 were in the range of 0.24–0.68 μg/L, and the enrichment factors were in the range of 121–136. The results demonstrate that this method was successfully applied to determine pyrethroid insecticides in real water samples. No centrifugation or any special apparatus are required, make this a promising method for rapid field-sampling procedures. [ABSTRACT FROM AUTHOR]

In this research, an effervescence-assisted β-cyclodextrin/attapulgite composite (β-CD/ATP) for the in-syringe dispersive solid-phase extraction (EAIS-DSPE) of pyrethroids in environmental samples was developed for the first time. A syringe was used to conduct the extraction procedure and a small amount of β-CD/ATP was dispersed into the solution with the release of carbon dioxide when the effervescent tablet components dissolved in water. Then, the sorbent was recovered using a filter membrane, and the analytes were directly eluted using acetonitrile. In the process, the β-CD/ATP sorbent resulted in an excellent extraction efficiency compared to commercially available sorbents such as C 18 and HLB. Moreover, in the extraction procedure, both the β-cyclodextrin inclusion interactions (especially the hydrophobic effects) and the special structure of the ATP contributed to the efficient enrichment of pyrethroids in aqueous media. The amount of β-CD/ATP sorbent, the volume of desorption, the ratio of NaH 2 PO 4 /Na 2 CO 3 , the volume of the sample, and the pH were screened using a Plackett–Burman design. All factors affecting the procedure were optimized by applying a central composite design. Under the optimized conditions, a good repeatability (RSDs) ranging from 1.7 to 2.3, linearity (2.5–500 μg L −1 ), limits of detection (LODs) (0.15–1.03 μg L −1 ), and an acceptable recoveries (76.8–86.5%) were achieved. Finally, the proposed method was successfully applied for the determination of pyrethroids in environmental samples including river water, reservoir water and lake water. [ABSTRACT FROM AUTHOR]

A novel dispersion liquid–liquid microextraction method based on the solidification of sedimentary ionic liquids (SSIL-DLLME), in which an in situ metathesis reaction forms an ionic liquid (IL) extraction phase, was developed to determine four pyrethroid insecticides (i.e., permethrin, cyhalothrin, fenpropathrin, and transfluthrin) in water followed by separation using high-performance liquid chromatography. In the developed method, in situ DLLME was used to enhance the extraction efficiency and yield. After centrifugation, the extraction solvent, tributyldodecylphosphonium hexafluorophosphate ([P 44412 ][PF 6 ]), was easily collected by solidification in the bottom of the tube. The effects of various experimental parameters, the quantity of tributyldodecylphosphonium bromide ([P 44412 ]Br), the molar ratio of [P 44412 ]Br to potassium hexafluorophosphate (KPF 6 ), the ionic strength, the temperature of the sample solution, and the centrifugation time, were optimized using a Plackett–Burman design to identify the significant factors that affected the extraction efficiency. These significant factors were then optimized using a central composite design. Under the optimized conditions, the recoveries of the four pyrethroid insecticides at four spiked levels ranged from 87.1% to 101.7%, with relative standard deviations (RSDs) ranging from 0.1% to 5.5%. At concentration levels between 1 and 500 µg/L, good linearity was obtained, with coefficients of determination greater than 0.9995. The limits of detection (LODs) for the four pyrethroid insecticides were in the range of 0.71–1.54 µg/L. The developed method was then successfully used for the determination of pyrethroid insecticides in environmental samples. [ABSTRACT FROM AUTHOR]

Abstract: A novel and facile microextraction technique, termed as ionic liquid-linked dual magnetic microextraction (IL-DMME), was developed for the determination of pyrethroids in honey samples. The distinct advantage of the proposed method is that high recoveries can be readily achieved through the combination of dispersive liquid–liquid microextraction (DLLME) and dispersive microsolid-phase extraction (D-μ-SPE) with the aid of synthetic ionic liquid and non-modified magnetic nanoparticles (MNPs), respectively. In the first DLLME step, [C6MIM]NTf2 was used to extract the pyrethroids without the addition of any toxic dispersive solvent. In the following D-μ-SPE steps, non-modified MNPs were added to retrieve the ionic liquid. The effect of different variables on the extraction efficiency was studied simultaneously using the response surface methodology. The Plackett–Burman design was first employed to screen for the variables that significantly affected the extraction efficiency. Central composite design (CCD) was then introduced to optimize the significant factors using a polynomial fit. The optimal experimental conditions obtained from this statistical evaluation included: ionic liquid volume, 75μL; S-BaFe quantity, 60mg; sonication time, 4min; vortex time, 100s; desorption time, 150s; and no addition of salt. Under the optimal conditions, good linearity in the range of 0.5μgL−1–500μgL−1, repeatability (RSD 1.1–3.8%), low LODs (0.03–0.05μgL−1) and good recovery (86.7–98.2%) were obtained. Finally, the developed method was evaluated for the extraction and determination of four pyrethroids in real honey samples. [Copyright &y& Elsevier]

• Uniform and mechanically-free dispersion method; • Green and economic extractant; • Short extraction time. Deep eutectic solvents (DESs) were used as an extractant for the determination of pyrethroids in environmental water and tea beverage samples. Three different acids were chosen as hydrogen bond donors for preparation of DESs, and decanoic acid was optimal because of its high recovery. Factors affecting relative recovery were optimized individually, including salt addition, surfactant addition, extraction temperature, DES amount, and sample volume etc. Under the optimized experimental conditions, the relative recovery of pyrethroids was from 89.3% to 97.7%, with relative standard deviation (RSD) values ranging from 1.75% to 2.73%. The linear correlation coefficient ranged from 0.9981 to 0.9992, and the linear range was between 1.9 and 500 μg/L. Based on a signal-to-noise ratio (S/N) of 3:1, the limit of detection (LOD) values were 0.56 to 1.24 μg/L. The enrichment factor ranged from 92 to 105. In conclusion, good extraction efficiency was achieved in tea beverage samples under the optimized conditions. [ABSTRACT FROM AUTHOR]

• The sorbent attapulgite grafted covalent organic frameworks was synthesized by a mild condition. • The parameters affecting the ATP@COFs-based DSPE were optimized. • Rapid adsorption and desorption were obtained in this method. • The method was successfully applied to extract pyrethroids in environmental water samples. A facile synthetic method of attapulgite@covalent organic frameworks was reported in this study. The composite was synthesized by covalently grafting covalent organic frameworks (synthesized from 1,3,5-triformylphloroglucinol and p -phenylenediamine) onto attapulgite at room temperature and was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, zeta potential analysis, transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller measurement. The synthesized nanocomposite was used as a sorbent in dispersive solid phase extraction to extract pyrethroids from environmental water samples, and the parameters affecting the extraction efficiency were optimized. The linear range of the four pyrethroids was 2.5–500 μg L−1, and the enrichment factors ranged from 65.0 to 68.2. The method detection limits were between 0.83 and 1.79 μg L−1 under the optimal conditions. In addition, the intra-day and inter-day precision were 1.4%–4.8% and 2.7%–3.6%, respectively. Finally, the method was successfully applied to extract pyrethroids from real water samples with relative recoveries ranging from 71.2% to 88.7%. [ABSTRACT FROM AUTHOR]

A method was developed using dispersive solid-phase extraction based on hyperbranched polymer functionalized with β-cyclodextrin for extraction and enrichment of three pyrethroid pesticides (fenpropathrin, cyhalothrin, and ethofenprox) in environmental water samples before high-performance liquid chromatography analysis. The aim of this research was to establish a simple, high-speed, effective, and sensitive method for the detection of target analytes. The as-prepared sorbents were synthesized successfully, and characterized by scanning electron microscopy, energy dispersive spectroscopy, elemental analysis, Brunauer-Emmett-Teller measurement and Fourier transform infrared spectroscopy. The experimental factors influencing the extraction efficiency such as extraction time, pH, ionic strength, desorption conditions, etc. were optimized. Good linearity was observed for all three pyrethroids, and the linear range of fenpropathrin was 10–500 ng/mL, and cyhalothrin, ethofenprox were 5–500 ng/mL. The method detection limits were ranged from 1.0 ng/mL to 2.1 ng/mL under the optimal conditions. The recoveries achieved ranged from 83.1% to 91.6% for the extraction of the three target analytes. Apart from these, the relative standard deviation (intra-day and inter-day) were measured fewer than 6.0%. The method in this work was applied to the rapid enrichment and detection of pyrethroids in environmental water samples. • The sorbent β-cyclodextrin grafted hyperbranched polymer (CD-HBP) was synthesized. • The optimized method was validated in terms of sorbent type, sorbent amount, extraction time, ionic strength, solution pH and desorption conditions. • The proposed DSPE method was applied to extract pyrethroids in environmental water samples. • FTIR was adopted to investigate the adsorption mechanism between CD-HBP and the analytes. [ABSTRACT FROM AUTHOR]