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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

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.

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.

A magnetic graphene/polydopamine (MG/PDA) nanocomposite has been prepared and used as sorbent for magnetic dispersive solid-phase extraction (MDSPE) of four benzoylurea insecticides in environmental water samples. The obtained nanocomposites were characterized by transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, powder X-ray diffraction, fourier transform infrared spectroscopy, surface area and porosity analysis and thermogravimetric analysis. To investigate the adsorption performance of MG/PDA for target analytes, various parameters affecting the MG/PDA-based MDSPE procedure were optimized. Under the optimal conditions, the established method exhibits good linearity (R2 ≥ 0.9988) in the concentration range 2.5–500 µg L−1. A low limit of detection (0.75 µg L−1, signal/noise = 3:1), a low limit of quantification (2.50 µg L−1, signal/noise = 10:1), and good precision (intraday relative standard deviation ≤3.6%, interday relative standard deviation ≤4.5%) are also achieved. Finally, the simple, fast, and sensitive sample preparation technique was successfully used to determine benzoylurea insecticides in environmental water samples.

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.

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.

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.

A new microextraction technique named in-syringe low-density ionic liquid dispersive liquid–liquid microextraction (LDIL-DLLME) followed by separation using high performance liquid chromatography has been developed to determine the levels of four pyrethroid insecticides (i.e., deltamethrin, fenvalerate, permethrin, and bifenthrin) in environmental water samples. In the developed method, an ionic liquid (IL) was used for the first time instead of an organic solvent, which is most often used in low-density solvent-based microextraction methods. The IL was placed in a long syringe needle using a microsyringe. It was then dispersed by drawing the sample solution into the syringe. The extraction was finished in the syringe, taking full advantage of the low-density property, and making this method easier and quicker. Several parameters affecting the experimental efficiency of LDIL-DLLME, such as the needle's inner diameter, salt addition, the volume of IL and sample, rotation speed and duration of centrifugation and ultrasound were thoroughly studied. Under optimized conditions, in the range of 1 to 500 μg L−1, good linearity was obtained, with coefficients of determination greater than 0.9994. Three spiked water samples were studied, and recovery ranged from 88.0 to 102.8%, with relative standard deviations (RSDs) ranging from 0.3 to 6.7%. The limits of detection (LODs) for the four pyrethroid insecticides were in the range of 0.88–1.71 μg L−1 and enrichment factors (EFs) were in the range of 242 to 257. The proposed method provides an inexpensive, rapid, simple and eco-friendly process for evaluating pyrethroid insecticides in environmental samples, making it a potential method for the pretreatment of experimental samples.

A novel and simple method for effervescence-assisted dispersive liquid–liquid microextraction based on the solidification of a floating ionic liquid using a special collection method combined with high-performance liquid chromatography is developed for the determination of four benzoylureas in water samples. In this method, the ionic liquid (IL), trihexyl(tetradecyl)phosphonium tetrafluoroborate, is used rather than organic drops, which have limitations, as the extraction solvent for the first time in dispersive liquid–liquid microextraction based on the solidification of floating organic drops (DLLME-SFO). Due to the high viscosity of the IL, it can be quickly collected in the lid of the centrifuge tube after solidification, which combines the advantages of both dispersive liquid–liquid microextraction and liquid phase microextraction based on the solidification of a floating IL. Furthermore, effervescence is used to disperse the IL, thereby avoiding the use of an organic dispersant. The influence of various experimental factors, such as the form of the effervescent material, IL quantity, base to acid ratio in the effervescent tablet, weight ratio of IL to effervescent tablet, ultrasonication time, centrifugation time, extraction temperature, sample pH, extraction time and salt addition, are optimized using a central composite design and the one-factor-at-a-time approach. Under the optimal conditions, good linearity was obtained for the four BUs from 2 to 500 μg L−1, with correlation coefficients ranging from 0.9994 to 0.9995. The recoveries were 90.2–100.2% with relative standard deviations ranging from 1.3–4.4%. The limits of detection for the analytes were between 0.77 to 1.58 μg L−1, and the enrichment factors ranged from 206 to 228. Additionally, this method was successfully applied for the determination of four BUs in real water samples.

A novel dispersive liquid–liquid microextraction (DLLME) method is proposed for the detection of five acaricides (clofentezine, fenpyroximate, diafenthiuron, pyridaben and spirodiclofen) in tea infusions prior to analysis by high-performance liquid chromatography (HPLC). For this method, a nanofluid prepared by dispersing magnetic zinc oxide nanoflower (FeO4@ZnO) nanoparticles in 1-octyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonimide) was used as an extractant. After extraction, the nanofluid was magnetically collected by the addition of FeO4@ZnO nanoparticles without centrifugation. In DLLME, the joint use of an ionic liquid (IL)-based nanofluid and magnetic retrieval is unprecedented and makes this microextraction process rapid and effective. The main parameters affecting the extraction efficiency were optimized by an orthogonal experiment and a single-factor experiment using tea infusions. Under the optimal conditions, the recoveries of the analytes were between 83.0 and 104.4%, the limits of detection ranged from 0.44 to 1.0 μg L−1, and the intra-day precision and inter-day precision were both lower than 7.5%. The proposed method was successfully applied to the analysis of acaricides in four tea infusions, and the recoveries were between 79.2 and 93.1%, with RSDs of 0.4 to 5.8%. The developed method is promising as an environmentally friendly, convenient, and efficient sample preparation technique.

A novel liquid phase microextraction method based on the solidification of floated ionic liquids (SFIL-LPME) was developed to determine four phthalate esters (diethyl phthalate, diallyl phthalate, benzyl butyl phthalate, and dicyclohexyl phthalate) in environmental waters and bottle beverages and subsequently separate them using high-performance liquid chromatography. In this work, we customized a tributyldodecylphosphonium tetrafluoroborate ([P4 4 4 12][BF4]) ionic liquid (IL) to obtain a low density such that it can be solidified at a low temperature, and then used as an extraction solvent in liquid-phase microextraction based on the solidification of floated organic drops (SFO-LPME). This means that more potential ILs can be customized to broaden extraction solvents in SFO-LPME. To identify the significant factors that affect extraction efficiency, parameters such as the volume of [P4 4 4 12][BF4], the extraction time, the rotation speed, the extraction temperature and the ionic strength were optimized using a Plackett–Burman design. A central composite design was then used to optimize the identified significant factors to study the effect of interactions on the experiment. Under these optimized conditions, the extraction recoveries of the four phthalate esters in water samples ranged from 73.0 to 94.6% and in bottled beverage were from 70.2 to 101.3%, with relative standard deviations (RSDs) ranging from 0.6 to 8.2% and 0.6 to 7.8%. Good linearity for both water samples and bottled beverages were obtained in the range of 5–500 μg L−1, with correlation coefficients greater than 0.9993. The limits of detection for the four phthalate esters varied from 0.27 to 1.1 μg L−1 for water samples and 1.22 to 2.36 μg L−1 for bottled beverages. The two developed methods were then successfully applied to the determination of phthalate esters in environmental waters and bottled beverages.

A graphene-modified, magnetic polypyrrole nanocomposite (Fe 3 O 4 @PPy/RGO) was fabricated through a facile chemical route and its application as an adsorbent for the removal of a dye was also demonstrated. The as-prepared Fe 3 O 4 @PPy/RGO nanocomposite was characterized by Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), N 2 adsorption–desorption, and zeta potential analysis techniques. The Fe 3 O 4 @PPy/RGO nanocomposite showed excellent water dispersibility because of the hydrophilicity of Fe 3 O 4 and RGO. Adsorption experiments indicated that Fe 3 O 4 @PPy/RGO adsorbs methylene blue fast and efficiently, with an adsorption capacity of up to 270.3 mg g −1 . The kinetic adsorption data fit the pseudo-second-order model and the isotherm data followed the Langmuir model. Additionally, adsorption of MB on Fe 3 O 4 @PPy/RGO also can utilize the electrostatic interaction and π–π interaction between Fe 3 O 4 @PPy/RGO and MB. Moreover, compared to other nanoparticle adsorbents, the as-prepared Fe 3 O 4 @PPy/RGO is highly flexible and easy to operate and retrieve. Most importantly, it is easy to disperse, which enables its potential application in wastewater treatment.

A novel and simple ionic-liquid-mingled air-assisted liquid–liquid microextraction based on solidification of floating organic droplets combined with high performance liquid chromatography was developed for the determination of six benzoylureas (BUs) in water and honey samples. In this method, a mixture of low-density and low melting point extraction solvents and aqueous sample solutions was rapidly sucked up and injected several times using a glass syringe. The influence of the main factors on the efficiency of this procedure is studied. Under the optimal conditions, the enrichment factors (EFs) for BUs were acquired in the range of 144 to 187, limits of detection (LODs) were between 0.01 and 0.1 μg L−1 and limits of quantitation (LOQs) were changed in the range of 0.03 and 0.33 μg L−1. The obtained extraction recoveries ranged from 84.03% to 109.20% with intra-day lower than 4.5%, and inter-day precision lower than 6.5%. The method is successfully applied to determine the BUs in environmental water and honey samples with recoveries in the range of 78.57–109.72%, which proved the potential use of this method in real samples.

A series of 6-O-benzoyl-beta-cyclodextrins (CDs) with methyl, methoxy, methoxycarbonyl, and bromo substituent(s) at the ortho-, meta-, and/or para-position(s) were synthesized as chiral sensitizing hosts for the use in supramolecular enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to its chiral (E)-isomer (1E). The complex stability constants (K(S)) of the modified beta-CDs with 1Z in aqueous methanol solutions were highly sensitive to the substituent(s) introduced to the benzoate moiety, and the log K(S) values decreased linearly with slightly different slopes with increasing methanol content. The enantiomeric excess (ee) of 1E obtained upon photosensitization with these hosts was a critical function of the size and position of the substituent, varying from almost zero to 46% ee. This indicates that even an apparently small structural difference between methyl and methoxy can critically affect the enantiodifferentiating photoisomerization of a guest included in the chiral cavity, probably through manipulation of both the orientation of ground-state 1Z and the subsequent rotational relaxation of excited 1Z inside the chiral cavity.

A type of ultrasound-assisted emulsification‐microextraction (USAEME) was applied for the extraction and determination of four phthalate esters (e.g., dimethyl phthalate, diethyl phthalate, dibutyl phthalate and benzyl butyl phthalate) in aqueous samples prior to quantification using HPLC-UV. The simultaneous injection of the extraction solvent and ultrasonication of the mixture results in an efficient extraction with the extractant well-dispersed in the sample. The parameters affecting the experimental results were analyzed and optimized through the design of the experiment. Using a central composite face-centered design, the results of 28 experimental data points were analyzed and validated. An optimal set of operating conditions was obtained using 40 mL of 1,1,2,2-tetrachloroethane and 1% NaCl subjected to 2.0 min of ultrasonication under natural pH. Under optimized conditions, the extractions resulted in analyte recoveries of 75‐87% and high enrichment factors of 356‐415. The calibration curves were linear, and the correlation coefficients ranged from 0.9992 to 0.9997 at concentrations of 5 to 300 m gL 21 . The RSDs (n 5 5) were 5.6‐7.9%. The limits of detection for the four phthalate esters ranged from 0.26 to 1.46 m gL 21 .

An in situ ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a new approach for the detection of four pyrethroid pesticides in environmental water samples. The method is fast, simple, accurate and environmentally friendly. The hydrophobic ionic liquid, [C8MIM]-NTf2, formed by the water-soluble ionic liquid [C8MIM]Cl and the ion exchange reagent LiNTf2 was used as the extraction solvent. The experimental parameters affecting the extraction efficiency, including the amount of the IL, the extraction and the centrifugation times and the salt concentration were investigated and optimized using an orthogonal array design (OAD). A suitable molar ratio of LiNTf2 to [C8MIM]Cl on the recoveries of analytes was determined after OAD optimization. The method showed a good linear response in the range of 0.5 to 500 µg L-1 with correlation coefficients (R2) above 0.9998. The relative standard deviation (RSD) varied from 0.6 to 1.9%. The enrichment factor, the limit of detection and recovery ranged from 134 to 153, 0.02 to 0.18 µg L-1 and 89.7 to 95.6%, respectively. For water samples, the RSD ranged from 0.02 to 2.34% and the recovery ranges from 91.4 to 99.9%.

Inclusion complexes of beta-cyclodextrin (beta-CD) with sodium octyl sulfonate (C8As), sodium dodecyl sulfonate (C12As), and sodium hexadecyl sulfonate (C16As) in aqueous solutions are studied by surface tension measurement at the air/water interface at different temperatures. At fixed concentrations of the surfactants, the surface tension increases with an increase in beta-CD concentration to a maximum value, at which it holds. The surface tension curves of the surfactants in the presence of beta-CD are higher than those in the absence of beta-CD. The curves rise higher with the increase in beta-CD concentration for each surfactant. The apparent critical micelle concentrations (CMC*) of the surfactants vary linearly with beta-CD concentration. The CMC* and surface tension values (including those after the CMC*) for the same system decrease with increase in temperature. A numerical method based on surface tension measurements is developed to determine the association constants for 1:1 inclusion complexes. This method is very reliable and easy to perform. The results demonstrate that the longer the hydrophobic tail of the surfactant, the greater the association constant with beta-CD, and that for the same surfactant the association constant is higher at lower temperatures.

THE TITLE COMPOUND [SYSTEMATIC NAME: (2S*,3S*,4R*,5R*,9S*,11S*,15R*)-5,15-diacet-oxy-3-nicotino-yloxy-14-oxolathyra-6(17),12(E)-diene], C(30)H(37)NO(7), was isolated from the seeds of Euphorbia lathyris. The tricyclic diterpenoid molecule contains an 11-membered ring, a five-membered ring exhibiting an envelope conformation and a three-membered ring. The 11-membered ring is cis-fused with the three-membered ring and trans-fused with the five-membered ring.

In the crystal structure of the title macrocyclic diterpenoid [systematic name: (2S*,3S*,4R*,5R*,7R*,9S*,11S*,15R*)-5,15-diacet­oxy-14-oxolathyra-6(17),12(E)-diene-3,7-diyl di­ben­z­oate], C38H42O9, the mol­ecule exhibits the tricyclic terpenoid skeleton of lathyrane, consisting of fused five-, 11- and three-membered rings. The five-membered ring adopts an envelope conformation. Intra- and inter­molecular weak C—H⋯O hydrogen bonding helps to stabilize the crystal structure.

The title compound [systematic name: (1S,6R,7S,10S)-7-isopropyl-10-methyl-4-methyl­enedeca­hydro­naphthalene-6,10-diol], C15H26O2, was isolated from the rhizome of Acorus calamus L. The mol­ecule contains two fused six-membered rings, each in a chair conformation. The mol­ecules are linked together by inter­molecular O—H⋯O hydrogen bonding.