betadex and 4-nitrophenol

The present study reports the development of an electrochemical sensor based on sulfobutylether-β-cyclodextrin modified reduced graphene oxide hybrid (SBCD-rGO) for simultaneous detection of nitrophenol isomers. First, SBCD-rGO hybrid was synthesized and detailed characterized. Afterwards, a sensor was fabricated via the modification of glassy carbon electrode (GCE) with SBCD-rGO, and its electrochemical detection performances were also investigated. Then, the constructed electrochemical sensor was applied to detect nitrophenol isomers by voltammetry analysis. The results suggested that the sensitivities were 389.26, 280.88 and 217.19 μA/mM for p-nitrophenol (p-NP), m-nitrophenol (m-NP), and o-nitrophenol (o-NP), respectively, and their corresponding detection limits were all about 0.05 μM. Significantly, the combination of voltammetry analysis with the constructed sensor and data analysis by multiple linear regression realized the simultaneous detection of nitrophenol isomers.

Topics: beta-Cyclodextrins; Carbon; Electrochemical Techniques; Electrodes; Graphite; Isomerism; Limit of Detection; Nanostructures; Nitrophenols; Reproducibility of Results

In this paper, the modified multi-walled carbon nanotubes were prepared by β-cyclodextrin denoted as β-CD-MWNTs. The structure and morphology of β-CD-MWNTs was characterized by TEM and the dynamic adsorption of p-nitrophenol on β-CD-MWNTs was studied by the Thomas model. Some affecting factors of dynamic adsorption and the adsorbent regeneration process such as the sewage concentration, the amount of absorbent in column, including the type of reagent, solid-liquid ratio, regeneration time, and regeneration times were investigated and optimized. The results indicated that the p-nitrophenol removal rate could reach 84% under stuffing 2 g β-CD-MWNTs. The curves of p-nitrophenol's dynamic adsorption conformed to the Thomas model. Moreover, the adsorption capacity of regenerated β-CD-MWNTs was similar to the fresh β-CD-MWNT column. The optimal conditions of regenerations of β-CD-MWNTs were shown as follows: the type of reagent is anhydrous ethanol, the solid-liquid ratio is 200:40 (mg/mL) and the regeneration time is 120 min.

Topics: Adsorption; beta-Cyclodextrins; Cyclodextrins; Models, Chemical; Nanotubes, Carbon; Nitrophenols

In the present work, a noncovalent and eco-friendly approach was proposed to prepare a carbon-black/β-cyclodextrin (CB/β-CD) nanocomposite. CB/β-CD-nanocomposite-modified screen-printed carbon electrodes were applied for the simultaneous determination of the anticancer drug flutamide (Flut) and the environmental pollutant 4-nitrophenol (4-NP). The electrochemical performance of the proposed sensor relied on the conductivity of CB, the different binding strengths of the guests (Flut and 4-NP) to the host (β-CD), and the different reduction potentials of the nitroaromatic compounds. Fascinatingly, the proposed sensor exhibited an excellent electrochemical performance with high sensitivity, selectivity, and reproducibility. The obtained wide linear ranges were 0.05-158.3 and 0.125-225.8 μM for Flut and 4-NP. The low detection limits of 0.016 and 0.040 μM with the higher sensitivities of 5.476 and 9.168 μA μM

Topics: Antineoplastic Agents, Hormonal; beta-Cyclodextrins; Carbon; Drinking Water; Environmental Pollutants; Flutamide; Humans; Nanocomposites; Nitrophenols

A sensitive and selective fluorescent method for detection of cholesterol based on β-cyclodextrin functionalized carbon quantum dots (β-CD-CQD) nanoprobe through competitive host-guest recognition has been developed. The bright fluorescence of β-CD-CQD nanoprobe can be effectively quenched by the introduction of a very small amount of p-nitrophenol, and strong quenching ability of p-nitrophenol to the probe was identified. This efficient fluorescence quenching as a static quenching is due to the formation of nonfluorescent complex between β-CD-CQD and p-nitrophenol induced by host-guest interaction between them. Cholesterol, as a more suited guest molecule of β-cyclodextrin, can form an inclusion complex with β-cyclodextrin with a much greater binding constant than p-nitrophenol. As a result, the presence of cholesterol causes a replacement of guest molecule of β-CD moiety in the probe through a competitive way, and the inclusion of cholesterol in the probe as the removal of p-nitropheonl induces significant fluorescence enhancement. The fluorescence recovery can be achieved by continuous addition of cholesterol. In terms of this relationship between enhanced fluorescence and concentration of cholesterol, a quantitative measurement for cholesterol based on β-CD-CQD nanoprobe has been established. Under the optimized detection conditions, this method shows good analytical performance in detection of cholesterol with lowest detection limit of 0.7±0.1µM and a relatively wide linear scope of 110µM. Specificity test and complex matrix test show that this method possesses excellent selectivity to cholesterol, and complex matrix such as serum does not exert apparent influence on the analytical performance, which enables its use in practical serum samples.

Topics: Animals; beta-Cyclodextrins; Biosensing Techniques; Carbon; Cattle; Cholesterol; Fluorescence; Fluorometry; Limit of Detection; Nitrophenols; Quantum Dots

The tumor-specific sensitive fluorescence sensing of cellular alkaline phosphatase (ALP) activity on the basis of host-guest specific and pH sensitivity was conducted on coated surfaces and aqueous states. Cross-linked fluorescent nanoparticles (C-FNP) consisting of β-cyclodextrin (β-CD)/boronic acid (BA) and fluorescent hyaluronic acid [FNP(HA)] were conjugated to fluorescent polydopamine [FNP(pDA)]. To determine the quenching effect of this system, hydrolysis of 4-nitrophenyl phosphate (NPP) to 4-nitrophenol (NP) was performed in the cavity of β-CD in the presence of ALP activated photoinduced electron transfer (PET) between NP and C-FNP. At an ALP level of 30-1000 U/L, NP caused off-emission of C-FNP because of their specific host-guest recognition. Fluorescence can be recovered under pH shock due to cleavage of the diol bond between β-CD and BA, resulting in release of NP from the fluorescent system. Sensitivity of the assays was assessed by confocal imaging not only in aqueous states, but also for the first time on coated surfaces in MDAMB-231 and MDCK cells. This novel system demonstrated high sensitivity to ALP through generation of good electron donor/acceptor pair during the PET process. Therefore, this fluorescence sensor system can be used to enhance ALP monitoring and cancer diagnosis on both coated surfaces and in aqueous states in clinical settings.

Topics: Alkaline Phosphatase; Animals; beta-Cyclodextrins; Carbon; Cell Line, Tumor; Cross-Linking Reagents; Dogs; Fluorescence; Fluorescent Dyes; Humans; Hydrogen-Ion Concentration; Indoles; Madin Darby Canine Kidney Cells; Nanoparticles; Nitrophenols; Organophosphorus Compounds; Particle Size; Polymers; Solutions; Surface Properties; Water

Here we report the use of β-cyclodextrin polyurethane nanosponges cross-linked with 1,6-hexamethylene diisocyanate as a template for the preparation of Aun quantum clusters, by the core-etching of glutathione-capped Au nanoparticles. The study of temporal evolution of the core-etching process using different Au concentrations indicated that formation of Aun clusters embedded in the nanosponge is favored by the use of lower Au concentrations, since it began at shorter times and lead to higher cluster loading. An estimation of the number of Au atoms based on the maximum photoluminescence wavelength suggested that, depending on the Au concentration and the core etching time, clusters with 11-15 atoms were formed. After excluding the possibility of an inclusion complex formation, evaluation of the catalytic activity of nanosponge-loaded Aun clusters toward the reduction of 4-nitrophenol has shown that the reaction is catalyzed by the Aun clusters with no induction time, following the Langmuir-Hinshelwood kinetic model.

Topics: beta-Cyclodextrins; Catalysis; Glutathione; Gold; Isocyanates; Models, Molecular; Molecular Conformation; Nitrophenols; Oxidation-Reduction; Polyurethanes; Quantum Dots

Flower-like ruthenium-copper (RuCu) nanodendrites were readily synthesized by RuCl3·xH2O and CuCl with oleylamine as the reducing agent, stabilizer and solvent. The nanodendrites contained various small particles and demonstrated efficient catalytic ability in the hydrogenation of p-nitrophenol as a model reaction. Notably, by adding β-cyclodextrin, the reaction rate can be greatly enhanced.

Topics: beta-Cyclodextrins; Catalysis; Copper; Hydrogenation; Nanostructures; Nitrophenols; Ruthenium; Spectrophotometry, Ultraviolet

A convenient, reliable and highly sensitive assay for alkaline phosphatase (ALP) activity in the real-time manner is developed based on β-cyclodextrin-modified carbon quantum dots (β-CD-CQDs) nanoprobe through specific host-guest recognition. Carbon quantum dots were first functionalized with 3-aminophenyl boronic acid to produce boronic acid-functionalized CQDs, and then further modified with hydropropyl β-cyclodextrins (β-CD) through B-O bonds to form β-CD-CQDs nanoprobe. p-Nitrophenol phosphate disodium salt is used as the substrate of ALP, and can hydrolyze to p-nitrophenol under the catalysis of ALP. The resulting p-nitrophenol can enter the cavity of β-CD moiety in the nanoprobe due to their specific host-guest recognition, where photoinduced electron transfer process between p-nitrophenol and CQDs takes place to efficiently quench the fluorescence of the probe. The correlation between quenched fluorescence and ALP level can be used to establish quantitative evaluation of ALP activity in a broad range from 3.4 to 100.0U/L with the detection limit of 0.9U/L. This assay shows a high sensitivity to ALP even in the presence of a very high concentration of glucose. This study demonstrates a good electron donor/acceptor pair, which can be used to design general detection strategy through PET process, and also broadens the application of host-guest recognition for enzymes detection in clinical practice.

Topics: Alkaline Phosphatase; Animals; beta-Cyclodextrins; Biosensing Techniques; Carbon; Cattle; Enzyme Assays; Fluorometry; Limit of Detection; Nitrophenols; Organophosphorus Compounds; Quantum Dots

One-pot green approach to the synthesis of Prussian blue nanocubes/reduced graphene oxide (PBNCs/RGO) nanocomposite had been attempted. It was based on the extract of mushroom with K3[Fe(CN)6] and graphene oxide (GO) as precursors, where the reduction of GO and the deposition of PBNCs occurred simultaneously. The obtained nanocomposite was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy and electrochemical techniques. With the introduction of β-cyclodextrin (β-CD), the β-CD/PBNCs/RGO system showed linear behavior in the range from 0.01 to 700 μM for 4-nitrophenol with a low detection limit of 2.34 nM (S/N=3).

Topics: Agaricales; beta-Cyclodextrins; Electrochemical Techniques; Ferrocyanides; Graphite; Microscopy, Electron, Transmission; Nanocomposites; Nanotubes; Nitrophenols; Oxidation-Reduction; Oxides; Spectrum Analysis, Raman; Water

A rapid and sensitive electrochemical sensor based on disulfides bridged β-cyclodextrin dimer-functionalized multi-walled carbon nanotube (DBβ-CD-MWCNT) nanohybrids with higher supramolecular recognition capability was successfully constructed for the first time. Simultaneous trace analysis of three phenols (4-aminophenol, 4-AP; 4-chlorophenol, 4-CP; 4-nitrophenol, 4-NP) in tap-water and wastewater samples was performed based on the constructed sensor. Cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy were utilized to characterize the properties of the modified electrode. The proposed DBβ-CD-MWCNT-modified electrode displayed electrochemical signal superior to those of β-CD-MWCNT and MWCNT towards 4-AP, 4-CP, and 4-NP. Under optimal conditions, differential pulse voltammetry was used to simultaneously quantify 4-AP, 4-CP, and 4-NP within the concentration range of 0.01-20, 0.1-200, and 0.1-200 µM, respectively. The detection limits (S/N=3) of the DBβ-CD-MWCNT nanohybrid electrode for 4-AP, 4-CP, and 4-NP were 0.0042, 0.028, and 0.048 µM, respectively. Satisfactory results revealed that this proposed electrochemical sensor can provide a promising candidate for the simultaneous trace analysis of 4-AP, 4-CP, and 4-NP in environmental monitoring of water and wastewater samples. The present work might broaden the channel toward the application of bridged CD in the electrochemical sensing or biosensing.

Topics: Aminophenols; beta-Cyclodextrins; Biosensing Techniques; Chlorophenols; Dielectric Spectroscopy; Environmental Monitoring; Limit of Detection; Nanotubes, Carbon; Nitrophenols

Polymeric sorbent materials that incorporate beta-cyclodextrin (CD) have been prepared and their sorption behavior toward two model agrochemical contaminant compounds, p-nitrophenol (PNP) and methyl chloride examined. The sorption of PNP was studied in aqueous solution using ultraviolet-visible (UV-Vis) spectroscopy, whereas the sorption of methyl chloride from the gas phase was studied using a Langmuir adsorption method. The sorption results for PNP in solution were compared between granular activated carbon (GAC), modified GAC, CD copolymers, and CD-based mesoporous silica hybrid materials. Nitrogen porosimetry at 77 K was used to estimate the surface area and pore structure properties of the sorbent materials. The sorbents displayed variable surface areas as follows: copolymers (36.2-157 m(2)/g), CD-silica materials (307-906 m(2)/g), surface modified GAC (657 m(2)/g), and granular activated carbon (approximately 10(3) m(2)/g). The sorption capacities for PNP and methyl chloride with the different sorbents are listed in descending order as follows: GAC > copolymers > surface modified GAC > CD-silica hybrid materials. In general, the differences in the sorption properties of the sorbents were related to the following: (i) surface area of the sorbent, (ii) CD content and accessibility, (iii) and the chemical nature of the sorbent material.

Topics: Adsorption; Agrochemicals; beta-Cyclodextrins; Charcoal; Methyl Chloride; Nitrophenols; Silicon Dioxide; Water Pollution, Chemical; Water Purification

Sorption properties of surface modified activated carbon (AC) with p-nitrophenol (PNP) and methylene blue (MB) in aqueous solution were investigated. The calculated surface areas for AC and surface modified AC were compared using nitrogen sorption and a dye-based method. The surface areas of AC and the surface modified AC with glutaraldehyde (AC-β-CD) (1:10:10⁹) and 1,4-phenylene diisocyanate (ACPDICD) measured by nitrogen sorption were 1,269 m²/g, 103 m²/g, and 95 m²/g, respectively (Langmuir model) and 956 m²/g, 74 m²/g, and 69 m²/g (BET model), respectively. However, the calculated surface areas for the dye-based method (PNP; pH 6.00) for AC, AC-β-CD(1:10:10⁹), and ACPDICD was 1,035 m²/g, 814 m²/g, and 76 m²/g (Langmuir model), respectively and 1,491 m²/g, 1,669 m²/g, and 92 m²/g (BET model), respectively. The corresponding surface areas for the dye-based method (MB; pH 8.40) for AC-β-CD(1:10:10⁹) and ACPDICD was 263 m²/g and 171 m²/g (Langmuir model), respectively and 1019 m²/g and 182 m²/g (BET model), respectively. The sorption capacity (Q(m)) and binding affinity characteristics [K(F)(L/g), K(L)(g/mol), and K(BET)(L/g)] were estimated at room temperature at equilibrium conditions using several sorption isotherm models.

Topics: Adsorption; beta-Cyclodextrins; Charcoal; Methylene Blue; Nitrophenols

A soil bacterium strain, capable of using p-nitrophenol (PNP) as its sole source of carbon and energy, was isolated by enrichment on minimal salt medium (MSM). On the basis of a phylogenetic analysis of 16S rRNA gene sequences the bacterium is a species of Arthrobacter, closely related to Arthrobacter ureafaciens DSM 20126. This strain has an unusually high substrate tolerance for PNP degradation in MSM. Greatest degradation of PNP was observed at 30 degrees C and under slightly alkaline pH (pH 7-9) conditions. Effective degradation rates slowed as the concentration of PNP was increased. Addition of glucose from 0.1% to 0.5% generally enhanced the degradation of PNP at high concentration (400 mg/l) although acidification as a result of glucose metabolism had a negative effect on PNP depletion. Biodegradation of PNP at high concentration was greatly accelerated by beta-cyclodextrin at a concentration of 0.5%, indicating that beta-cyclodextrin could be a promising addictive for effective PNP bioremediation.

Topics: Arthrobacter; beta-Cyclodextrins; Biodegradation, Environmental; Carbon; Culture Media; Hydrogen-Ion Concentration; Nitrophenols; Temperature

The surface of zeolite was modified by cationic beta-cyclodextrin (CCD), which was synthesized with 2, 3-epoxypropyltrimethylammonium chloride (ETMAC) and beta-cyclodextrin (beta-CD), to prepare a novel and effective sorbent for removal of p-nitrophenol (p-NP) from aqueous solution. FTIR, SEM and EDS were used to characterize the surface modification. It was found that CCD, which was synthesized at different conditions such as the mole ratio of ETMAC against beta-CD and pH, made an impact on sorption capacity of p-NP on CCD-modified zeolite (CCDMZ). Given ETMAC: beta-CD = 7:1 and pH = 13, the cationic process of beta-CD might be optimum for CCD to bond to zeolite surfaces. In addition, CCD concentration and modification time affected sorption capacity of p-NP on CCDMZ too. The sorption of p-NP on CCDMZ, activated zeolite (AZ) and natural zeolite (NZ) was investigated by contact time, initial p-NP concentration and sorption isotherms with the batch sorption experiments. The results showed that the sorption of p-NP on CCDMZ satisfactorily fitted the known Langmuir model and the sorption capacity of CCDMZ was higher than that of AZ and NZ although the contact time of CCDMZ appeared to be shorter than other two.

Topics: Adsorption; beta-Cyclodextrins; Cations; Chemistry Techniques, Analytical; Hydrogen-Ion Concentration; Kinetics; Nitrophenols; Quaternary Ammonium Compounds; Spectroscopy, Fourier Transform Infrared; Surface Properties; Temperature; Time Factors; Water; Water Purification; Zeolites

With more accurate simulation models and more efficient algorithms becoming available, the binding constants of an affinity interaction can be obtained from much simpler experiments using capillary electrophoresis. With the enumeration algorithm, all possible combinations of the binding constant and the complex mobility in certain ranges that could result in the experimental migration time of an injected analyte are extracted from a 3-D surface, which depicts the migration times resulting from different values of the binding constant and the mobility of the complex formed between the interacting pair, to form a 2-D curve. When the experimental conditions are changed, the analyte migration time will also change. A new 2-D curve can be constructed from another 3-D surface on the basis of the pairs of binding constants and complex mobility values that could result in the new migration time. Because the true binding constant and complex mobility values have to be the same for both experimental conditions under the same temperature, there has to be a point where both 2-D curves will converge. The coordinates of the converging point give the values for a binding constant and a complex mobility that will fit all 2-D curves generated under certain experimental conditions. p-Nitrophenol is used as the analyte, beta-cyclodextrin is used as the additive, and a one-cell model is used to simulate affinity CE. The experimental conditions that can improve the accuracy of the binding constants are discussed.

Topics: Algorithms; beta-Cyclodextrins; Electrophoresis, Capillary; Nitrophenols; Regression Analysis

Microcapsules were prepared by interfacial cross-linking of beta-cyclodextrins (beta-CD) with terephthaloyl chloride (TC). Batches were prepared from beta-CD solutions in 1 M NaOH, using 5% TC and a 30 min reaction time. Microcapsules were studied with respect to morphology (microscopy), size (laser diffraction technique) and, for selected batches, IR spectroscopy, determination of beta-CD content (polarimetry after alkaline dissolution of microcapsules) and complexing properties, evaluated using p-nitrophenol (pNP) as the guest molecule. Well-formed microcapsules were obtained from 5, 7.5, and 10% beta-CD solutions. The mean size of all batches was in the 10-35 microm range. The IR spectrum showed bands at 1724, 1280 and 731 cm(-1), reflecting the formation of esters. The beta-CD contents were 46, 56-58 or 60-66% for batches prepared from 5, 7.5 or 10% beta-CD solutions, respectively. The experiments conducted with 1 mM pNP showed a rapid complexation reaching a maximum within 1 h. When incubating 50 mg lyophilized microcapsules in 10 ml pNP solution, the maximal fixation (97.8 micromol/g microcapsules) was observed for small-sized particles ( approximately 11 microm) prepared from a 7.5% beta-CD solution. The method then appears as a simple and rapid procedure to provide stable microcapsules, having an interesting guest-binding ability.

Topics: beta-Cyclodextrins; Capsules; Cross-Linking Reagents; Cyclodextrins; Drug Compounding; Food Additives; Nitrophenols; Phthalic Acids

The interaction between beta-cyclodextrin and five mono- and disubstituted benzenes in water was investigated by means of molecular dynamics. The trajectories were calculated for each system, imposing a 1:1 host-guest stoichiometry with 512 water molecules. Periodic boundary conditions were adopted. The results account for the formation of stable adducts and the predicted geometry agrees with experimental circular dichroism data.

Topics: Aniline Compounds; Benzene; beta-Cyclodextrins; Catechols; Computer Simulation; Cyclodextrins; Models, Molecular; Nitrophenols; Phenol

The formation and molecular geometry of inclusion complexes of some branched cyclomaltaoses with p-nitrophenol in aqueous solution have been investigated by using high-resolution 1H-n.m.r. spectroscopy. 6-O-(alpha-Maltosyl)cyclomalto-hexaose and -heptaose were found to form 1:1 inclusion complexes with p-nitrophenol, and the dissociation constants for their complexes are quite similar to those for corresponding unbranched cyclomaltaose-p-nitrophenol complexes, indicating that formation of these inclusion complexes is not hampered by the maltosyl branch. From measurement of nuclear Overhauser enhancements, it was concluded that the maltosyl branch is not situated over the entrance of the cavity.

Topics: beta-Cyclodextrins; Carbohydrate Sequence; Cyclodextrins; Magnetic Resonance Spectroscopy; Maltose; Molecular Sequence Data; Nitrophenols; Solutions

The synthesis is described of a derivative of cyclomaltoheptaose (beta-cyclodextrin) to which the tripeptide Ser-His-Asp, the catalytic triad found in chymotrypsin, has been coupled. The derivative enhanced the rates of hydrolysis of activated esters, as measured by the release of p-nitrophenol, and the formation of amine bonds.

Topics: Amides; Amino Acid Sequence; beta-Cyclodextrins; Carboxylic Acids; Chemical Phenomena; Chemistry; Chymotrypsin; Cyclodextrins; Dextrins; Esters; Hydrolysis; Nitrophenols; Oligopeptides; Starch