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Three patterns for the detection of fenpyroximate based on the response signal of gold nanoparticles.

Pesticides are used in the agricultural production process to ensure the yield and quality of agricultural products. However, in recent years, environmental pollution issues caused by pesticide residues have sparked widespread concern in society. It is important to develop convenient and efficient approaches to detect and monitor pesticide residues. In this study, targeting benzoylurea insecticides (BUs), polyamidoamine dendrimer-functionalized silica nanocomposite with polydopamine coating (SiO

In this study, a 4-formylphenylboronic acid-modified cross-linked chitosan magnetic nanoparticle (FPBA@CCHS@Fe

Catalytic enantiodifferentiating photoisomerization of cyclooctene (1Z) included and sensitized by regioisomeric 6-O-(o-, m-, and p-methoxybenzoyl)-β-cyclodextrins (CDs) was performed under a variety of solvent conditions for higher enantioselectivities. The enantiomeric excess (ee) of chiral (E)-isomer (1E) produced was a critical function of all the internal and external factors examined, in particular, the sensitizer structure and the solvent conditions, to afford (R)-1E in record-high ee's of up to 67% upon sensitization with the meta-substituted β-CD host in water and salt solutions but neither in 50% aqueous ethanol nor with the ortho- and para-substituted hosts. The mechanistic origin of the sudden ee enhancement achieved under the specific conditions is discussed on the basis of the circular dichroism spectral behaviors upon substrate inclusion and the compensatory enthalpy-entropy relationship of the activation parameters for the enantiodifferentiating photoisomerization.

Perfluoro octanoic acid was modified on the surface of magnetic hyperbranched polyamideamine by acid amine condensation. The morphology and chemical composition of perfluoro octanoic acid-modified magnetic hyperbranched polyamideamine was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, zeta potential, particle size analysis, Brunauer-Emmett-Teller measurement, and X-ray photoelectron spectroscopy. Perfluoro octanoic acid-modified magnetic hyperbranched polyamideamine was applied in magnetic solid phase extraction for the separation and enrichment of four fluorine-containing pesticides (indoxacarb, metaflumizone, cyflumetofen, and cyhalothrin). The magnetic solid phase extraction method based on perfluoro octanoic acid-modified magnetic hyperbranched polyamideamine has low method detection limits (0.30-0.49 μg/L), a satisfactory coefficient of determination (0.9995-0.9999), wide linear ranges (2.5-250 μg/L), and good repeatability (intraday: 2.6-4.7%; interday: 1.1-7.9%). The enrichment factors and extraction efficiences varied from 55 to 76 and 69 to 96%, respectively. The sorbent-to-sorbent reproducibility was in the range of 3.2-7.6%, indicating that the synthesis of the sorbent was reliable. For the detection of actual water samples, the relative recoveries were in the range from 80.1 to 114.4% with relative standard deviations less than 9.6%. The calculation results of quantum chemistry calculations showed that after the modification of perfluoro octanoic acid, the interaction between the sorbent and four fluorine-containing pesticides was stronger.

The identification of residual thiram (Tr) in foods is vital in view of its harmful effects on human health. Herein, a ratiometric fluorescence sensor (I

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.

The Tyndall Effect assay (TEA) has been applied into colorimetric metal ion detection since 2019. However, the TEA-based sensor for pesticide detection has never been reported till now. Herein, a facile fluorescent organic nanoparticle (FON)-based sensor is firstly developed for fluorine-containing pesticide detection through ratiometric fluorescence assay (FLA) and TEA. For FLA, the intensity of the second-order Tyndall scattering peak (STS

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.

A new, simple colorimetric aptasensor based on the aggregation-induced color change of citrate-stabilized AuNPs was designed for the specific and sensitive determination of ametryn. Citrate-stabilized AuNPs with negative surface charges were synthesized via an easy one-pot reaction. Because of the electrostatic interaction between the three-nitrogen hybrid ring of ametryn and gold nanoparticles, the citrate-stabilized AuNPs easily undergo aggregation in the presence of ametryn. Thus, with a color change from wine red to gray, ametryn was visually detected by a colorimetric aptasensor. In addition, the detection result can also be measured quantitatively using a UV-vis spectrophotometer. The aptasensor has good selectivity and sensitivity to ametryn in the linear range of 0–80.0 μg L−1. According to the IUPAC criteria (3σ rule), the detection limit of ametryn is 0.15 μg L−1. Moreover, the aptasensor was successfully applied to the detection of ametryn in Yongding River from Zhaocun, Yizhuang Jingkai Sewage Treatment Plant and Yizhuang Nokia Factory water samples. The recovery reached 98.9–101.6%, 95.7–101.3% and 100.0–103.3%, respectively. The excellent performance of the colorimetric aptasensor in the detection of ametryn indicates its potential applications in the detection of ametryn in more complex environmental samples.

Ultraviolet/persulfate (UV/PS) and Ultraviolet/hydrogen peroxide (UV/H

Catalytic enantiodifferentiating photoisomerization of cyclooctene (

The fluorescent organic nanoparticles (FONs)-based sensor has been attracting great attention in recent years. There are still big challenges in the preparation and application of FONs-based sensor. In this study, a FONs-based sensor was designed and developed through facile hydrothermal process using 3-perylenecarboxaldehyde (PlCA) as the fluorophore and L-methionine (Met) as the recognition site for mercury ions. According to the experimental results, the fluorescence intensity of the as-prepared PlCA-M would decrease when adding Hg

In this paper, a simple and innovative colorimetric method is established, which is based on DBP-induced aggregation of arginine functionalized gold nanoparticles (ARG-AuNPs), and can be used for the sensitive determination of dibutyl phthalate (DBP) in Baijiu samples. The morphological characteristics and the color changes of ARG-AuNPs caused by aggregation show good sensitivity, and can be observed through ultraviolet-visible spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential technology. The color change of ARG-AuNPs from red to blue is due to the strong non-covalent interactions between DBP and ARG-AuNPs (electrostatic, van der Waals force and hydrogen bonding), which leads to the reduction of the electrostatic repulsion between the nanoparticles and aggregation. A two-stage linear equation was established between the absorption ratio (A690/A530) and the DBP concentration (0.0-2.8 mg L-1); the correlation coefficient (R2) was 0.9914-0.9940, and the detection limit (LOD) was estimated at 0.05 mg L-1. The designed ARG-AuNPs acting as a dependable sensor for the detection of Baijiu samples equally acquired satisfactory recoveries. When the concentration of DBP in the solution is more than 1.0 mg L-1, the color change can be clearly observed by the naked eye; so there is no need for sample preparation techniques and tedious operations to quickly and semi-quantitatively detect DBP. The successful application of the proposed method in Baijiu samples indicates its potential to detect DBP in more complex environment samples.

A turn-on fluorescent sensing platform based on an ultralow concentration of Al-metal organic frameworks for the detection of aflatoxin B

Chemosensors based on traditional fluorescent dyes have always contributed to the development of chemical sensor areas. In this review, the rhodamine-based chemosensors’ improvements and applications from 2018 to 2022 are discussed, mainly focusing on cations (metal ions and H+), anions (CN−, F−, etc.), and small bio-functional molecules’ (thiols, amino acids, etc.) detection. Specifically, this review highlights the detection target, detection limit, detection solution system, detection mechanism, and performance of the rhodamine-based sensors. Although these rhodamine-based sensors are well developed, their repeatability and sensitivity still need significant improvement. This review is expected to bring new clues and bright ideas to researchers for further advances in rhodamine-based chemosensors in the future.

In this study, a novel FONs-based sensor P-M(w) was synthesized using 1-Pyrenecarboxaldehyde and L-methionine through facile hydrothermal strategy. The fluorescence emission peaks of the acquired P-M(w) would show specific changes after the addition of Hg

Hyperbranched polytriazine functionalized with humic acid was prepared and developed as new sorbents for dispersive solid-phase extraction of three acaricides (clofentezine, fenpyroximate, and pyridaben) in tea samples combined with high-performance liquid chromatography detection. The sorbents were characterized by scanning electron microscopy, energy dispersive spectroscopy, Zeta-potential, and Fourier transform infrared spectroscopy. The extraction parameters (extraction time, ionic strength, desorption conditions) were optimized. The adsorption mechanism was evaluated utilizing Fourier transform infrared spectra. Under optimum conditions, satisfactory analytical performances were achieved, which included high precision (1.33-9.62%), low limits of detection (0.19-3.54 µg/L), and wide linear range (2.5-500 µg/L) for the analysis of the acaricides. Moreover, the proposed method proved highly effective for the determination of acaricides in tea samples, with the relative recoveries in the range of 65.20-108.13% and relative standard deviations < 9.87%. The method has great application potential for the detection of acaricides in tea samples.

In this study, a green and effective ultrasound-assisted dispersive liquid-liquid microextraction method based on a hydrophobic deep eutectic solvent (UA-DLLME-DES) was developed for the preconcentration and determination of pyrethroid insecticides (deltamethrin, fenvalerate, permethrin, etofenprox, and bifenthrin) in environmental water samples using high-performance liquid chromatography combined with an ultraviolet detector (HPLC-UVD). Hydrophobic deep eutectic solvents (DESs) are green solvents prepared by mixing quaternary phosphonium salts and straight-chain monobasic acids. DESs were synthesized and characterized by Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). Several key parameters, including the types and amounts of DESs, pH value, sample volume, ultrasound time, salt addition, and centrifugation rate and time, were researched and optimized. Under the optimal experimental conditions, the proposed method required only a small amount of DES to complete extraction and recovery in a very short time. The validated method showed good linearity, with a coefficient of determination (R2) ranging from 0.9992 to 0.9995, and good repeatability, with relative standard deviations (RSDs) ranging from 1.45 to 4.86%, for all analytes. The limits of detection (LODs) varied from 0.30 to 0.60 μg/L. Finally, the presented method was implemented to determine the pyrethroid insecticides in environmental water samples, and acceptable recoveries within the range of 80.93–109.88% were obtained.

In this work, a method for the analysis of benzoylurea insecticides, including hexaflumuron, flufenoxuron, lufenuron and chlorfluazuron, in tea samples by high-performance liquid chromatography with Fe3 O4 -hyperbranched polyester nanocomposite as the adsorbent for magnetic solid-phase extraction was developed. The magnetic nanocomposite was prepared and characterized by infrared spectroscopy, vibrating sample magnetometry, and scanning electron microscopy. The as-prepared nanocomposite was used as a sorbent for the extraction and preconcentration of pesticide residues in tea samples. The extraction and desorption conditions, including mass ratios of raw materials, amount of sorbent, pH value, extraction time, and desorption time, were investigated. Under the final conditions chosen for the analysis, good linearity was obtained for all the tested compounds, with R2 values of at least 0.9979. The limits of detection were determined in the range of 0.15-0.3 μg/L. The recovery obtained from the analysis of tea samples with various spiked concentrations was between 90.7 and 98.4%, with relative standard deviations (n = 4) lower than 4.1%. Furthermore, the present approach was successfully applied to the quantitative determination of residues of benzoylurea insecticides in real samples.

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.

Herein, a novel hyperbranched aromatic polyamide-coated magnetic sorbent was prepared by in situ polymerization on the surface of amino-functionalized Fe3 O4 nanoparticles. The magnetic sorbent was characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, elemental analysis, Brunauer-Emmett-Teller measurement, and X-ray photoelectron spectroscopy, etc. The new magnetic sorbent was used in the magnetic solid-phase extraction for the detection of seven benzoylurea insecticides. Under optimum conditions, low method detection limits (0.56-1.20 ng/mL), acceptable coefficient of determination (0.9967-0.9996), wide linear ranges (2.5-500.0 ng/mL), and good repeatability (intraday: 2.0-7.3%; interday: 1.9-9.2%) were achieved. The magnetic solid-phase extraction method based on the new magnetic sorbent showed good reliability in the analysis of seven benzoylurea insecticides in real water samples, as the relative recoveries were in the range from 80.1 to 116.3% with satisfactory RSDs (0.1-9.8%). By means of density functional theory and semiempirical quantum mechanical, the binding configuration and interaction energy of hyperbranched aromatic polyamide and benzoylurea insecticides were calculated. The result of theoretical calculation revealed that the adsorption of benzoylurea insecticides by hyperbranched aromatic polyamide was derived from hydrogen bonding and π-π stacking. The contribution of π-π stacking was greater than that of hydrogen bond, which was confirmed by energy decomposition analysis.

In this study, a simple, rapid, precise, and environmentally friendly microextraction named dispersive micro-solid phase extraction based on a graphene/polydopamine composite as a sorbent was investigated for the analysis of four pyrethroids (fenpropathrin, cyhalothrin, etofenprox and bifenthrin) in water samples. The graphene/polydopamine composite was successfully synthesized using a one-step method, and was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy and X-ray photoelectron spectroscopy. The simplicity and rapidity of dispersive micro-solid phase extraction and the high surface area and adsorptivity of the graphene/polydopamine composite were combined in the proposed method. Several main parameters, including the amount of the sorbent, extraction time, ionic strength and desorption conditions, were independently optimized and the results were compared to find the best extraction setup for dispersive micro-solid phase extraction. Under the optimal conditions, good linearity was observed for all the target analytes, with the coefficient of determination ranging from 0.9997 to 0.9999. The extraction recoveries obtained using the proposed method ranged from 76.81% to 85.29%, and the limits of detection varied from 1.5 to 3 μg L−1. In addition, the relative standard deviation values for the intra-day precision were between 0.41% and 3.00%, while the inter-day precision showed relative standard deviation values ranging from 1.61% to 5.59%. Overall, the figures of merit of the entire procedure showed that this technique could produce satisfactory results in the detection of pyrethroids in water samples or other organic pollutants in the future.

Several hyperbranched polysilicon (HBPS) materials with different end group modifications were designed and synthesized and the structures were characterized. The modified HBPS polymers were applied to the adsorption of benzoylurea insecticides (BUs). The binding mode and binding energy between the HBPS and BUs were quantified and the results of an adsorption kinetics study and an adsorption thermodynamics experiment were verified by calculation and mutual verification. The adsorption mechanism of BUs onto HBPS was also discussed. The theoretical results show that the most effective way to combine the adsorbent and BUs is via hydrogen bonding when the end group is an amino group. Moreover, the most effective combination when the end group is β-cyclodextrin is the interaction of the BUs with the interior of the cavity to form a host–guest coating. The theoretical results of other end group-modified HBPS materials were also obtained and verified by adsorption experiments. In this work, an experimental method for obtaining the binding mode by theoretical calculations and then verifying it according to adsorption experiments was established.

In this study, a novel FONs-based sensor P-M(w) was synthesized using 1-Pyrenecarboxaldehyde and L-methionine through facile hydrothermal strategy. The fluorescence emission peaks of the acquired P-M(w) would show specific changes after the addition of Hg2+ due to interfering the PET process and inducing nano-structure conformational rigidification of P-M(w). Notably, the water-soluble FONs-based sensor was firstly used to detect Hg2+ in tea samples providing a new material choice for the fluorescence sensor construction of metal ion detection. Besides, the qualitative and quantitative analysis of Hg2+ could be carried out with P-M (w) at a very low concentration (1 μg/mL) meaning that the acquired P-M(w) synthesized by few grams of reactants may satisfy the detection of approximate fifty thousand samples.

A pretreatment method using hyperbranched polyester (HBPE) composite as sorbent based on dispersive micro-solid-phase (d-μ-SPE) extraction preceding high-performance liquid chromatography analysis was developed for the determination of benzoylurea insecticides (BUs) in water samples. Parameters that may influence the extraction efficiency, such as the diameter and the amount of the sorbent, extraction and desorption time and the pH value of the solution, were investigated and optimized using batch and column procedures. Under optimized conditions, good linearity was obtained for all of the tested compounds, with r values of at least 0.9924. The linearity of the method was determined in the range of 1–25 000 μg L−1. The limits of detection (LODs) ranged from 0.024 to 0.068 μg L−1. The recoveries of the four benzoylurea insecticides in water samples increased from 85.50–96.12%. The results confirmed the possibility of using hyperbranched polyester in the determination of relatively hydrophobic trace pesticides residues. Finally, the proposed method was applied to the determination of BUs in water samples with satisfactory results.

A green, simple, inexpensive, and sensitive ionic liquid immobilized fabric phase sorptive extraction method coupled with high performance liquid chromatography was developed for rapid screening and simultaneous determination of four fungicides (azoxystrobin, chlorothalonil, cyprodinil and trifloxystrobin) residues in tea infusions. This IL modified extraction fiber is capable of extracting target analytes directly from complicated tea water matrices with the addition of surfactant. A series of extraction conditions were investigated by one-factor-at-a-time approach and orthogonal test. After a series experiments, the optimum conditions were found to be 10% [HIMIM]NTf2 as coating solution, 2min vortex time, 500μL acetonitrile as dispersive solvent and 2min desorption time. Under the above conditions, the proposed technique was applied to detect fungicides from real tea water samples with satisfactory results.

We present a novel dispersive liquid-liquid microextraction method based on the solidification of deep eutectic solvent coupled with high-performance liquid chromatography with a variable-wavelength detection for the detection of five benzoylureas in real water samples. In this work, a green solvent consisting of 1-octyl-3-methylimidazolium chloride and 1-dodecanol was used as an extraction solvent, yielding the advantages of material stability, low density, and a suitable freezing point near room temperature. Parameters that significantly affect extraction efficiency were optimized by the one-factor-at-a-time approach. Under optimal conditions, the recoveries of five target compounds were obtained ranging from 87.39 to 98.05% with correlation coefficients ranging from 0.9994 to 0.9997 for pure water. The limits of detection were in the range of 0.09-0.16 μg/L. The enrichment factors were in the range of 171-188. Linearities were achieved in the range of 0.5-500 μg/L. The proposed method was successfully applied to determine benzoylureas in environmental water samples with a satisfactory recovery of approximately 81.38-97.67%.

Phytophagous mites are usually considered a difficult problem for agricultural planting, and acaricides are applied to control diseases and pests. However, the overdose and misusage of acaricides causes pesticide residues. In this work, a simple and practical ionic liquid-based TiO 2 nanofluid, effervescence-assisted, dispersive liquid–liquid microextraction (EA-DLLME) method was developed to detect acaricides in honey and tea by high-performance liquid chromatography (HPLC-DAD). Oleophilic TiO 2 nanoparticles were synthesized by a facile solvothermal method to obtain greater stability of the nanofluid. The experimental parameters were optimized by a one-factor-at-a-time approach and included the effervescent tablet composition, ionic liquid selection, extractant composition, nanofluid volume, extraction temperature, extraction time and desorption conditions. Under the optimized conditions, the linear ranges of this proposed method were 0.5–500 μg L −1 , with correlation coefficients in the range of 0.9985–1.0000. The extraction efficiencies for the target analytes varied from 70.70 to 84.58%. The detection and quantitation limits were in the ranges of 0.04–0.18 μg L −1 and 0.13–0.60 μg L −1 , respectively. The intra- and inter-day relative standard deviations ( n = 3) were found to range from 2.32 to 5.71%, which showed perfect repeatability. Overall, the EA-DLLME method was time-saving and environmentally friendly, with future potential for microextraction.

In this research, a novel method using magnetic mixed hemimicelles dispersive solid-phase extraction (MMHDSPE) based on C16mimBr-coated attapulgite/polyaniline-polypyrrole/Fe3O4 (ATP/PANI-PPY/Fe3O4) nanocomposites were investigated for enrichment and separation of three acaricides in fruit juice. In this method, we combined the simplicity and speed of dispersive solid-phase extraction, the advantages of mixed hemimicelles and the facility of the phase separation of the magnetic nanoparticles to develop a simple, rapid, sensitive, and effective method for detecting target analytes from the juice samples. ATP/PANI-PPY/Fe3O4 nanocomposites were successfully synthesized using a one-pot method. The as-prepared nanocomposite sorbents were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The experimental factors affecting the extraction efficiency including the sorbent type, amount of ATP/PANI-PPY/Fe3O4 nanocomposites, volume of ILs, sonication time, pH, and desorption conditions were optimized. Under the optimal conditions, good linearity was observed for all target analytes, with correlation coefficients (r2) ranging from 0.9994 to 0.9999; the limits of detection (LOD) were in the range of 0.16-0.57μgL-1, and the recoveries of analytes using the proposed method ranged between 88.67% and 95.10%. The sorbents exhibited excellent repeatability in the range of 1.83-4.24% in extracting the three target analytes. In addition, the intra-day and inter-day precision values were found to be in the range of 0.19-6.24% and 2.23-8.36%, respectively. The method was successfully applied to analyze fruit juice samples by rapid preconcentration of acaricides.

In this study, low-density deep eutectic solvent combined with dispersive liquid-liquid microextraction was applied to the extraction of five benzoylurea insecticides (BUs, including diflubenzuron, triflumuron, hexaflumuron, flufenoxuron, and chlorfluazuron) from beverages. Then the extracted and concentrated samples were analyzed and detected using the high-performance liquid chromatography combined with an ultraviolet detector. The DESs were synthesized by [P14,6,6,6]Cl as hydrogen bond acceptor and tetradecyl alcohol as hydrogen bond donor, and then characterized by Fourier transform infrared spectroscopy. In the experiment, the key factors affecting the extraction efficiency were screened by Plackett-Burman design and optimized with the central composite design. The extraction recovery rates were 85.91–95.12%. The limits of detection and correlation coefficients of the method were 0.30–0.60 μg L−1 and 0.9992–0.9997. Finally, the method was applied to determine the BUs in four beverage samples, and satisfactory recoveries, within the range of 76.87–101.19% were achieved. The present method has the potential to be applied to the detection of BUs in aqueous samples.

The Fe3O4@MIL-100(Fe) hybrid composites are successfully synthesized via an in-situ growth method and characterized using various techniques. The ability of the magnetic metal–organic framework to promote photo-Fenton like processes is investigated using levofloxacin as a representative substrate. The results show that the composite with a Fe3O4:MIL-100(Fe) mass ratio of 1:4 has a higher degradation efficiency (up to 93.4%) than Fe3O4, MIL-100(Fe), and the other fabricated composites. This higher catalytic activity is ascribed to the synergistic effect between Fe3O4 and MIL-100(Fe), by which the quick separation of hole-electron pair from MIL-100(Fe) and the efficient reduction of Fe3+ to Fe2+ in the photo-Fenton reaction are mutually promoted. Moreover, the composite shows favorable recyclability without apparent loss of apparent photo-Fenton activity even after five cycles, and more importantly, can be recovered magnetically. The possible degradation mechanism and intermediates of levofloxacin in the photo-Fenton reaction have been tentatively proposed based on free radical quenching, electron paramagnetic resonance and mass spectrometry analysis. Finally, the developed Fe3O4@MIL-100(Fe) is successfully applied for the removal of levofloxacin from spiked wastewater with removal efficiencies ranging from 77.9 to 85.5%, which indicates that the proposed system has significant potential for wastewater treatment applications.

A magnetic Metal-Organic Frameworks composite material modified with attapulgite was prepared via in situ growth method and characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption and vibration sample magnetometer analysis. It was applied as an efficient adsorbent for the magnetic solid-phase extraction of seven benzoylurea insecticides from environmental water samples couple with high-performance liquid chromatography detection. Under the optimized experimental conditions, the established procedure exhibited low limit of detection ranging from 0.75 to 1.5 µg L−1 and good linear response ranging from 2.5 to 500 µg L−1 with coefficients of determination >0.99. The method recoveries of spiked analytes at the concentrations of 20, 100 and 200 µg L−1 in real water samples were 73.56–99.63% with the relative standard deviations

A pretreatment method using in-syringe dispersive liquid–liquid microextraction based on the direct solidification of ionic liquids before high performance liquid chromatography analysis was developed for the determination of benzoylurea insecticides (BUs) in honey samples. The hydrophobic ionic liquid [N4444][PF6], formed in situ by the hydrophilic ionic liquid [N4444]Cl and the ion exchange reagent KPF6, was used to extract the target analytes. The entire extraction procedure was performed in a syringe. The extractant was solidified at room temperature and collected using a nylon membrane filter. This technique did not require a dispersive solvent, vortex mixer, ultrasound bath, or centrifugation. The parameters affecting the extraction efficiency were investigated through an experimental design. Under the optimal conditions, the limits of detection for the four BUs varied from 0.21 to 0.42 μg L−1 in solution (2.1–4.2 μg kg−1 in honey). Good linearities were obtained in the range of 2–300 μg L−1, with coefficients of determination greater than 0.999. The recoveries of the four BUs ranged from 80.94% to 84.59%. The intra-day (n = 3) and inter-day (n = 3) relative standard deviations were less than 5.08%. Finally, the proposed method was applied to the determination of BUs in commercial honey samples with satisfactory results.

In this study, a simple effervescence-assisted dispersive solid-phase extraction method was developed to detect fungicides in honey and juice. Most significantly, an innovative ionic-liquid-modified magnetic β-cyclodextrin/attapulgite sorbent was used because its large specific surface area enhanced the extraction capacity and also led to facile separation. A one-factor-at-a-time approach and orthogonal design were employed to optimize the experimental parameters. Under the optimized conditions, the entire extraction procedure was completed within 3 min. In addition, the calibration curves exhibited good linearity, and high enrichment factors were achieved for pure water and honey samples. For the honey samples, the extraction efficiencies for the target fungicides ranged from 77.0 to 94.3% with relative standard deviations of 2.3–5.44%. The detection and quantitation limits were in the ranges of 0.07–0.38 and 0.23–1.27 μg·L−1, respectively. Finally, the developed technique was successfully applied to real samples, and satisfactory results were achieved. This analytical technique is cost-effective, environmentally friendly, and time-saving. This article is protected by copyright. All rights reserved

Fe 3 O 4 @nSiO 2 @mSiO 2 was prepared successfully and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), infrared spectrometer (FT-IR), BET surface area measurements and Zeta potential analysis techniques. The contact time, initial concentration of congo red, temperature and pH on adsorption capacity were studied. The adsorbent shows highly efficient adsorption properties, with maximum adsorption capacity of 1428 mg g − 1 for congo red, which is much higher than the other adsorbents (normally below 300 mg g − 1 ). The adsorption kinetics and isotherm of congo red on Fe 3 O 4 @nSiO 2 @mSiO 2 were systematically investigated and found that the adsorption kinetics and isotherm were well fitted by pseudo-second-order kinetic and Langmuir isotherm model.