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1.
A β‐cyclodextrin‐modified attapulgite composite was prepared and used as a dispersive micro‐solid‐phase extraction sorbent for the determination of benzoylurea insecticides in honey samples. Parameters that may influence the extraction efficiency, such as the type and volume of the eluent, the amount of the sorbent, the extraction time and the ionic strength were investigated and optimized using batch and column procedures. Under optimized conditions, good linearity was obtained for all of the tested compounds, with R2 values of at least 0.9834. The limits of detection were determined in the range of 0.2–1.0 μg/L. The recoveries of the four benzoylurea insecticides in vitex honey and acacia honey increased from 15.2 to 81.4% and from 14.2 to 82.0%, respectively. Although the β‐cyclodextrin‐modified attapulgite composite did not show a brilliant adsorption capacity for the selected benzoylurea insecticides, it exhibited a higher adsorption capacity toward relatively hydrophobic compounds, such as chlorfluazuron and hexaflumuron (recoveries in vitex honey samples ranged from 70.0 to 81.4% with a precision of 1.0–3.7%). It seemed that the logPow of the benzoylurea insecticides is related to their recoveries. The results confirmed the possibility of using cyclodextrin‐modified palygorskite in the determination of relatively hydrophobic trace pharmaceutical residues.  相似文献   

2.
Photoirradiation surface molecularly imprinted polymers for the separation of 6‐O‐α‐d ‐maltosyl‐β‐cyclodextrin were synthesized using functionalized silica as a matrix, 4‐(phenyldiazenyl)phenol as a light‐sensitive monomer, and 6‐O‐α‐d ‐maltosyl‐β‐cyclodextrin as a template. Fourier transform infrared spectroscopy results indicated that 4‐(phenyldiazenyl)phenol was grafted onto the surface of functionalized silica. The obtained imprinted polymers exhibited specific recognition toward 6‐O‐α‐d ‐maltosyl‐β‐cyclodextrin. Equilibrium binding experiments showed that the photoirradiation surface molecularly imprinted polymers obtained the maximum adsorption amount of 6‐O‐α‐d ‐maltosyl‐β‐cyclodextrin at 20.5 mg/g. In binding kinetic experiments, the adsorption reached saturation within 2 h with binding capacity of 72.8%. The experimental results showed that the adsorption capacity and selectivity of imprinted polymers were effective for the separation of 6‐O‐α‐d ‐maltosyl‐β‐cyclodextrin, indicating that imprinted polymers could be used to isolate 6‐O‐α‐d ‐maltosyl‐β‐cyclodextrin from a conversion mixture containing β‐cyclodextrin and maltose. The results showed that the imprinted polymers prepared by this method were very promising for the selective separation of 6‐O‐α‐d ‐maltosyl‐β‐cyclodextrin.  相似文献   

3.
Graphene/mono‐(6‐amino‐6‐deoxy)‐β‐cyclodextrin multilayer films composed of graphene sheet (GS) and mono‐(6‐amino‐6‐deoxy)‐β‐cyclodextrin (NH2β‐CD) were fabricated easily by two steps. First, negatively charged graphene oxide (GO) and positively charged mono‐(6‐amino‐6‐deoxy)‐β‐cyclodextrin (NH2β‐CD) were layer‐by‐layer (LBL) self‐assembled on glassy carbon electrode (GCE) modified with a layer of poly(diallyldimethylammonium chloride) (PDDA). Then graphene/mono‐(6‐amino‐6‐deoxy)‐β‐cyclodextrin (GS/NH2β‐CD) multilayer films were built up by electrochemical reduction of graphene oxide/mono‐(6‐amino‐6‐deoxy)‐β‐cyclodextrin (GO/NH2β‐CD). Combining the high surface area of GS and the active recognition sites on β‐cyclodextrin (β‐CD), the GS/NH2β‐CD multilayer films show excellent electrochemical sensing performance for the detection of DA with an extraordinary broad linear range from 2.53 to 980.05 µmol·L?1. This study offers a simple route to the controllable formation of graphene‐based electrochemical sensor for the detection of DA.  相似文献   

4.
To evaluate the effect of the preparation strategy on the enantioseparation performance of β‐cyclodextrin‐functionalized monoliths, a series of β‐cyclodextrin‐functionalized organic polymeric monolithic columns were prepared through two‐step, single‐step, and one‐pot approaches, using the same cyclodextrin, linker–spacer, and crosslinker. Physicochemical characterization of the columns was carried out by determining the morphology, β‐cyclodextrin density, permeability, and chromatographic efficiency. For each type of monolithic column, the enantioresolution of 22 chiral compounds, including mandelic acid derivatives, nonsteroidal anti‐inflammatory drugs, N‐derivatized amino acids, and herbicides, was comparatively studied under optimum chromatographic conditions. The β‐cyclodextrin‐functionalized monolithic columns prepared through the one‐pot approach exhibited higher enantioresolution for most chiral compounds, and they have the advantage of good controllability and simple preparation. On the other hand, the enantioresolution obtained on columns prepared through the single‐step approach was quite unsatisfactory, and therefore the effect of using different linking spacers and crosslinkers was studied. A significant improvement of enantioresolution for 2‐chloro‐mandelic acid was obtained by using N ,N‐methylenebisacrylamide instead of ethylene dimethacrylate as the crosslinker in the single‐step preparation.  相似文献   

5.
A novel solid phase microextraction fiber was prepared for the first time by using a sol–gel technique with hydroxypropyl‐β‐cyclodextrin‐functionalized reduced graphene oxide as the fiber coating material. The results verified that the β‐cyclodextrin was successfully grafted onto the surface of reduced graphene oxide and the coating possessed a uniform folded and wrinkled structure. The performance of the solid phase microextraction fiber was evaluated by using it to extract nine volatile aromatic compounds from water samples before determination with gas chromatography and flame ionization detection. Some important experimental parameters that could affect the extraction efficiency such as the extraction time, extraction temperature, desorption temperature, desorption time, the volume of water sample solution, stirring rate, as well as ionic strength were optimized. The new method was validated to be effective for the trace analysis of some volatile aromatic compounds, with the limits of detection ranging from 2.0 to 8.0 ng/L. Single fiber repeatability and fiber‐to‐fiber reproducibility were in the range of 2.5–9.4 and 5.4–12.9%, respectively. The developed method was successfully applied to the analysis of three different water samples, and the recoveries of the method were in the range from 77.9 to 113.6% at spiking levels of 10, 100, and 1000 ng/L, respectively.  相似文献   

6.
Enantiomers of Tröger's base were separated by capillary electrophoresis using 2IO‐, 3IO‐, and 6IO‐carboxymethyl‐α‐, β‐, and γ‐cyclodextrin and native α‐, β‐, and γ‐cyclodextrin as chiral additives at 0–12 mmol/L for β‐cyclodextrin and its derivatives and 0–50 mmol/L for α‐ and γ‐cyclodextrins and their derivatives in a background electrolyte composed of sodium phosphate buffer at 20 mmol/L concentration and pH 2.5. Apparent stability constants of all cyclodextrin–Tröger's base complexes were calculated based on capillary electrophoresis data. The obtained results showed that the position of the carboxymethyl group as well as the cavity size of the individual cyclodextrin significantly influences the apparent stability constants of cyclodextrin–Tröger's base complexes.  相似文献   

7.
An analytical protocol that includes solid‐phase purification and extraction is successfully developed for the determination of trace neonicotinoid pesticides in tea infusion. The method consists of a purification on amino‐functionalized mesoporous silica SBA‐15 followed by a solid‐phase extraction based on graphene oxide before ultra high performance liquid chromatography with tandem mass spectrometry analysis. Parameters that significantly affected the extraction of the neonicotinoids onto graphene oxide, such as the amount of adsorbent, extraction time, pH, elution solvent, etc. were optimized. The amino‐functionalized mesoporous silica SBA‐15 has been proved to be an efficient adsorbent for removal of polyphenols especially catechins from tea infusion. Graphene oxide exhibits a very rapid adsorption rate (within 10 min) and high adsorption capacities for neonicotinoids at low initial concentration (0.01–0.5 mg/L). The analysis method gave a good determination coefficient (r2 > 0.99) for each pesticide and high recoveries in the range of 72.2–95.0%. Powder X‐ray diffraction, Raman spectroscopy, transmission electron microscopy, and UV‐vis spectroscopy were utilized to identify the structure and morphology of graphene oxide. The adsorption driving force of neonicotinoids on graphene oxide mainly depends on π–π electron donor–acceptor interaction and electrostatic interaction.  相似文献   

8.
Highly conductive, crystalline, polymer electrolytes, β‐cyclodextrin (β‐CD)–polyethylene oxide (PEO)/LiAsF6 and β‐CD–PEO/NaAsF6, were prepared through supramolecular self‐assembly of PEO, β‐CD, and LiAsF6/NaAsF6. The assembled β‐CDs form nanochannels in which the PEO/X+ (X=Li, Na) complexes are confined. The nanochannels provide a pathway for directional motion of the alkali metal ions and, at the same time, separate the cations and the anions by size exclusion.  相似文献   

9.
A novel nanocatalyst was designed and prepared. Initially, the surface of magnetic graphene oxide (M‐GO) was modified using thionyl chloride, tris(hydroxymethyl)aminomethane and acryloyl chloride as linkers which provide reactive C═C bonds for the polymerization of vinylic monomers. Separately, β‐cyclodextrin (β‐CD) was treated with acryloyl chloride to provide a modified β‐CD. Then, in the presence methylenebisacrylamide as a cross‐linker, monomers of modified β‐CD and acrylamide were polymerized on the surface of the pre‐prepared M‐GO. Finally, palladium acetate and sodium borohydride were added to this composite to afford supported palladium nanoparticles. This fabricated nanocomposite was fully characterized using various techniques. The efficiency of this easily separable and reusable heterogeneous catalyst was successfully examined in Suzuki–Miyaura cross‐coupling reactions of aryl halides and boronic acid as well as in modified Suzuki–Miyaura cross‐coupling reactions of N‐acylsuccinimides and boronic acid in green media. The results showed that the nanocatalyst was efficient in coupling reactions for direct formation of the corresponding biphenyl as well as benzophenone derivatives in green media based on bio‐based solvents. In addition, the nanocatalyst was easily separable, using an external magnet, and could be reused several times without significant loss of activity under the optimum reaction conditions.  相似文献   

10.
In this work, a novel single sulfoether‐bridged cationic per(3,5‐dimethyl)phenylcarbamoylated‐β‐cyclodextrin separation material was prepared by thiol‐ene click chemistry and characterized by using FTIR spectroscopy, solid‐state 13C NMR spectroscopy and elemental analysis, which confirmed the correct structure. The separation material exhibited a good achiral separation performance for benzene homologues and phenylamine analogs, especially o‐xylene and m‐xylene, and m‐phenylenediamine and o‐phenylenediamine can be discriminated by the (3,5‐dimethyl)phenylcarbamoyl cyclodextrins. The chiral resolving ability of the separation material was evaluated by discriminating various isoxazolines, flavonoids, and β‐blockers in reversed‐phase high‐performance liquid chromatography. For isoxazolines, the material showed the best chiral discrimination toward 3‐aryl‐5‐(2‐oxopyrrolidin‐1‐yl)‐isoxazolines, where the resolution for 3ClPh‐OPr  reached 6.03. For flavonoids, it exhibited more efficient separation to the ones with more hydrophobic substituents, with a resolution of 5.93 for 6‐hydroxyflavanone. β‐Blockers were also enantioseparated satisfactorily on the material. The as‐prepared separation material is a good member of the thiol‐ene click derived cyclodextrin stationary phase family.  相似文献   

11.
A novel cyclodextrin intermediate, mono‐2A‐allylcarbamido‐2A‐deoxy‐permethylated β‐cyclodextrin, was synthesized by reacting allylamine and newly prepared mono‐2A‐azido‐2A‐deoxy‐permethylated β‐cyclodextrin by the Staudinger reaction and anchored onto porous silica beads by a one‐pot hydrosilylation and immobilization procedure to afford a novel chiral stationary phase. This stationary phase acts as a new member of the previous chiral stationary phase series immobilized on the cyclodextrin C2 position. This stationary phase depicted enantiomeric separation abilities toward a series of bicyclic and tricyclic racemates under reversed‐phase conditions. The resolutions for hesperetin and naringenin achieved on the current phase reached 3.91 and 1.11, respectively, much higher than the previous permethylated β‐cyclodextrin with the linkage at the C6 position.  相似文献   

12.
Reactions of 5-(p-aminophenyl)-10,15,20-triphenyl porphyrin (1) with Ru3(CO)12 or M(OCOCH3)2 (M=Ni,Mn) afforded metalloporphyrins(4-6),respectively.6-Deoxy-6-io-do-β-cyclodextrin(2) and mono(6-O-trifluoromethanesulfonyl) permethylated β-cyclodextrin(3) reacted with complexes 4-6 to give β-cyclodextrin bonded metal porphyrins (7-9) and permethylated β-cyclodextrin bonded me-tal porphyrins (10-12) respectively.These new complexes were identified by MS,IR,UV-visible and ^1H NMR spectra,and elemental analysis.  相似文献   

13.
A water‐soluble benzenesulfonamidoquinolino‐β‐cyclodextrin has been successfully synthesized in 30 % yield by incorporating a N‐(8‐quinolyl)‐p‐aminobenzenesulfonamide (HQAS) group to β‐cyclodextrin through a flexible linker. This compound exhibits a good fluorescence response in the presence of Zn2+ in water but gives poor fluorescence responses with other metal ions commonly present in a physiological environment under similar conditions. Fluorescence microscopic and two‐dimensional NMR experiments showed that benzenesulfonamidoquinolino‐β‐cyclodextrin could bind to the loose bilayer membranes. As a result, benzenesulfonamidoquinolino‐β‐cyclodextrin was found to act as an efficient cell‐impermeable Zn2+ probe, showing a specific fluorescent sensing ability to Zn2+‐containing damaged cells whilst exhibiting no response in the presence of healthy cells.  相似文献   

14.
This work documents the influence of the position of single carboxymethyl group on the β‐cyclodextrin skeleton on the enantioselectivity. These synthesized monosubstituted carboxymethyl cyclodextrin (CD) derivatives, native β‐cyclodextrin, and commercially available carboxymethyl‐β‐cyclodextrin with degree of substitution approximately 3 were used as additives into the BGE consisting of phosphate buffer at 20 mmol/L concentration, pH 2.5, and several biologically significant low‐molecular‐mass chiral compounds were enantioseparated by CE. The results indicate that different substituent location on β‐cyclodextrin skeleton has a significant influence on the enantioseparation of the investigated enantiomers. The enantioselectivity of 2IO‐regioisomer was better than with native β‐cyclodextrin. Comparable results to native β‐cyclodextrin were obtained for 6IO‐ regioisomer and the enantioselectivity of 3IO‐regioisomer was even worse than with native β‐cyclodextrin. Commercially available derivative of CD provides better resolutions than the monosubstituted carboxymethyl CD derivatives for most of the investigated analytes.  相似文献   

15.
Graphene oxide based molecularly imprinted polymers modified with β‐cyclodextrin were prepared as solid‐phase extraction column sorbents for specific recognition and sensitive detection of di(2‐ethylhexyl) phthalate in water samples. The morphology and composition of synthesized sorbents were characterized by scanning electron microscopy, thermo‐gravimetric analysis, Raman spectroscopy, and Fourier‐transform infrared spectroscopy. The conditions affecting the performance of extraction procedures such as desorption solvent types and volume, sample pH and volume were investigated. The loading capacity (8.2 μg/mg) of the prepared sorbents increased eight times after modification with β‐cyclodextrin. The developed extraction procedures coupled to high‐performance liquid chromatography exhibited good linearity (0.2–500 μg/L), low limit of detection (0.052 μg/L), and good precision (relative standard deviation?5.7%) under optimized conditions. The developed solid‐phase extraction technique with prepared sorbents has been successfully applied in extracting trace di(2‐ethylhexyl) phthalate from real natural waters with high efficiency, good selectivity, and desirable recoveries.  相似文献   

16.
In this study, porous sandwich structure Fe3O4 nanoparticles coated by polyhedral oligomeric silsesquioxanes and β‐cyclodextrin were prepared by surface polymerization and were used as the magnetic solid phase extraction adsorbent for the extraction and determination of carbaryl and carbofuran. The Fe3O4 nanoparticles coated with polyhedral oligomeric silsesquioxanes and β‐cyclodextrin were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, vibrating sample magnetometry, and scanning electron microscopy. After optimizing the extraction conditions, a method that combined magnetic solid phase extraction with high‐performance liquid chromatography was developed for the determination of carbaryl and carbofuran in apple. The method exhibited a good linearity in the range of 2–400 μg/kg for carbaryl and carbofuran (R= 0.9995), respectively. The limits of detection were 0.5 μg/kg of carbaryl and 0.7 μg/kg for carbofuran in apple, respectively. Extraction recoveries ranged from 94.2 to 103.1% with the preconcentration factor of 300 and the relative standard deviations were less than 5.9%. These results indicated that the method combined magnetic solid phase extraction with high‐performance liquid chromatography and was promising for the determination of carbaryl and carbofuran at trace amounts.  相似文献   

17.
Three‐dimensional graphene‐supported mesoporous silica@Fe3O4 composites (mSiO2@Fe3O4‐G) were prepared by modifying mesoporous SiO2‐coated Fe3O4 onto hydrophobic graphene nanosheets through a simple adsorption co‐condensation method. The obtained composites possess unique properties of large surface area (332.9 m2/g), pore volume (0.68 cm3/g), highly open pore structure with uniform pore size (31.1 nm), as well as good magnetic separation properties. The adsorbent (mSiO2@Fe3O4‐G) was used for the magnetic solid‐phase extraction of seven pesticides with benzene rings in different aqueous samples before high‐performance liquid chromatography. The main parameters affecting the extraction such as adsorbent amount, volume of elution solvent, time of extraction and desorption, salt effect, oscillation rate were investigated. Under the optimal conditions, this method provided low limits of detection (S/N = 3, 0.525–3.30 μg/L) and good linearity (5.0–1000 μg/L, R2 > 0.9954). Method validation proved the feasibility of the developed adsorbent, which has a high extraction efficiency and excellent enhancement performance for pesticides in this study. The proposed method was successfully applied to real aqueous samples, and satisfactory recoveries ranging from 77.5 to 113.6% with relative standard deviations within 9.7% were obtained.  相似文献   

18.
New hybrid organic–inorganic nanocomposites consist of β‐cyclodextrin (β‐CD)/epichlorohydrin (ECH), and bentonite clay were prepared by direct intercalation through one step emulsion polymerization. The structure and thermal stability of prepared nanocomposites were investigated by Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), field emission‐scanning electron microscopy (FE‐SEM), energy dispersive X‐ray analysis (EDAX), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), differential of differential scanning calorimetry (DDSC), thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analyses. The observed results show that the β‐CD polymer/clay nanocomposites (β‐CD–ECH polymer/clay) with higher thermal stability than β‐CD–ECH polymer were successfully prepared. The removal of heavy metals such as Cu(II), Zn(II) and Co(II) ions from drinking water was studied using a batch method at ambient temperature. The removal percentage and distribution coefficients (Kd) were determined for the adsorption system. It was found that the β‐CD–ECH polymer/clay nanocomposites showed higher removal capacity for Co2+, Cu2+ and Zn2+ ions in comparison with β‐CD–ECH polymer. The selectivity order could be given as Zn2+ > Cu2+ > Co2+. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

19.
The syntheses of well‐defined 7‐arm and 21‐arm poly(N‐isopropylacrylamide) (PNIPAM) star polymers possessing β‐cyclodextrin (β‐CD) cores were achieved via the combination of atom transfer radical polymerization (ATRP) and click reactions. Heptakis(6‐deoxy‐6‐azido)‐β‐cyclodextrin and heptakis[2,3,6‐tri‐O‐(2‐azidopropionyl)]‐β‐cyclodextrin, β‐CD‐(N3)7 and β‐CD‐(N3)21, precursors were prepared and thoroughly characterized by nuclear magnetic resonance and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. A series of alkynyl terminally functionalized PNIPAM (alkyne‐PNIPAM) linear precursors with varying degrees of polymerization (DP) were synthesized via atom transfer radical polymerization (ATRP) of N‐isopropylacrylamide using propargyl 2‐chloropropionate as the initiator. The subsequent click reactions of alkyne‐PNIPAM with β‐CD‐(N3)7 and β‐CD‐(N3)21 led to the facile preparation of well‐defined 7‐arm and 21‐arm star polymers, namely β‐CD‐(PNIPAM)7 and β‐CD‐(PNIPAM)21. The thermal phase transition behavior of 7‐arm and 21‐arm star polymers with varying molecular weights were examined by temperature‐dependent turbidity and micro‐differential scanning calorimetry, and the results were compared to those of linear PNIPAM precursors. The anchoring of PNIPAM chain terminal to β‐CD cores and high local chain density for star polymers contributed to their considerably lower critical phase separation temperatures (Tc) and enthalpy changes during phase transition as compared with that of linear precursors. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 404–419, 2009  相似文献   

20.
To further evaluate the feasibility and applicability of the one‐pot strategy in monolithic column preparation, two novel β‐cyclodextrin‐functionalized organic polymeric monoliths were prepared using two β‐cyclodextrin derivatives, i.e. mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin and heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin. In this improved method, mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin or heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin reacted with glycidyl methacrylate to generate the corresponding functional monomers and were subsequently copolymerized with ethylene dimethacrylate. The polymerization conditions for both monoliths were carefully optimized to obtain satisfactory column performance with respect to column efficiency, reproducibility, permeability, and stability. The obtained poly(glycidyl methacrylate‐mono(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) and poly(glycidyl methacrylate‐heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) monoliths exhibited a uniform structure, good permeability, and mechanical stability as indicated by scanning electron microscopy and micro‐high‐performance liquid chromatography experimental results. Because of the probable existence of multi‐glycidyl methacrylate linking spacers on the poly(glycidyl methacrylate‐heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin‐co‐ethylene dimethacrylate) monolith, the effect of the ratio of glycidyl methacrylate/heptakis(6‐amino‐6‐deoxy)‐β‐cyclodextrin was especially studied, and satisfactory reproducibility could still be achieved by strictly controlling the composition of the polymerization mixture. To investigate the effect of the degree of amino substitution of β‐cyclodextrin on column performance, a detailed comparison of the two monoliths was also carried out using series of analytes including small peptides and chiral acids. It was found that the β‐cyclodextrin‐functionalized monolith with mono‐glycidyl methacrylate linking spacers demonstrated better chiral separation performance than that with multi‐glycidyl methacrylate linking spacers.  相似文献   

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