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The effect of naphthalene-based additives: naphthalene (NPT), naphthalenesulfonate (NPTS) and hydroxynaphthalenesulfonate (HNPTS) on the kinetics of tin electrodeposition on a boron-doped diamond (BDD) electrode has been studied by means of chronoamperometry and scanning electron microscopy (SEM). Potentiostatic current transients in the absence and the presence of naphthalene-based additives are analyzed by using the Scharifker-Hills model. A strong decrease of the kinetics of tin nucleation on BDD was observed in the presence of naphthalene-based additives, NPT showing the smallest effect and HNPTS showing the largest effect. From the long-term Cottrell behavior of the transients, similar values of tin(II) diffusion coefficients were obtained for all additives, suggesting that there is no complexation of Sn(II) by the additives and that the charge-transfer kinetics itself is not substantially influenced by the presence of the additives. In the absence of additives, tin deposition on BDD displays a progressive nucleation and growth mechanism at the least negative potentials, switching to instantaneous nucleation and growth at more negative potential. In the presence of NPTS and HNPTS, progressive nucleation and growth transients are observed. The growth mode results are confirmed by the tin features observed in the scanning electron micrographs. In conclusion, NPT, NPTS and HNPTS mainly decrease the rate of the nucleation of tin deposition, most likely by blocking or reducing access to active nucleation sites. In comparison, ethoxylated alpha-napthalenesulfonic acid (ENSA, a commonly used additive in the tin plating industry) inhibits tin deposition process on BDD even more strongly. These observations show a striking similarity to our previous study of tin deposition on gold electrodes.

In the technology of synthesis of an additive for drywall based on polymethylene naphthalenesulfonate, it is proposed to carry out an additional stage - the Cannizzaro reaction, which allows reducing the mass fraction of residual formaldehyde. In the process of experimental studies, the effect of the additive on the plasticizing properties of the gypsum dough was revealed.

Poly (vinyl alcohol) (PVA) is a hydrophilic polymer developed for biomedical applications. Swelling properties of PVA gels is very important for its drug delivery applications. There are many ways to study the swelling behaviour. Here we are proposing a fluorescent study by using 8-anilino-1-naphthalenesulfonate (ANS) as an extrinsic fluorescent probe. When ANS incorporated PVA films are allowed to swell in water, there is a loss of fluorescence intensity at 453 nm and there is a new peak at 500 nm. Thus, ANS is proposed as a fluorescent probe for the sensing of hydration of PVA.

金沢大学理工研究域物質化学系, Molecular association between biocompatible dendritic polymers, dendrigraft poly-l-lysines (DGLs), and an anionic fluorescent probe, 8-anilino-1-naphthalenesulfonate (ANS-), was studied at the polarized water|1,2-dichloroethane (DCE) interface. The fluorescence intensity of ANS measured in aqueous solution was enhanced by the coexistence of DGLs over a wide pH range (2 < pH < 10), where ANS and DGL exist as a monoanionic form and a polycation, respectively. The voltammetric responses indicated that the positively charged DGLs were adsorbed at the water|DCE interface, whereas ANS- was transferred across the interface accompanied by the adsorption process. The interfacial behavior of the DGL-ANS associates was analyzed by potential-modulated fluorescence (PMF) spectroscopy. The PMF results demonstrated that the ion association between DGLs and ANS at the water|DCE interface is strongly affected by the applied potential and the dendritic generation of DGL. By applying appropriate potentials, the ANS anion was dissociated from its ion associate with DGLs at the interface and transferred into the organic phase, whereas DGLs remained in the aqueous phase. The Gibbs free energy of ion association (ΔGD···ANS) was estimated for the second-fourth generation DGLs (DGL-G2-G4) and the G4 polyamidoamine (PAMAM) dendrimer as a control. The highest stability of the DGL-G4-ANS associate manifested itself through ΔGD···ANS: DGL-G4-ANS (>G4 PAMAM dendrimer-ANS) > DGL-G3-ANS > DGL-G2-ANS. The results elucidated the efficient anion-binding ability of higher generation DGLs and its potential dependence at the liquid|liquid interface. © 2018 American Chemical Society., Embargo Periods 12 Months

The use of 2-naphthalenesulfonate (NAS) ligand in lanthanide chemistry afforded a family of isostructural mononuclear lanthanide complexes with the formula [Ln(NAS)2(H2O)6](NAS)·3H2O [Ln = Tb (1), Dy (2), Er (3), Yb (4)]. Crystallographic studies determined a square antiprismatic geometry (D4d) for the Ln centre and crystallization in an unprecedented chiral space group. The latter was further confirmed by the observation of Cotton effects in single crystal circular dichroism (CD) spectra. Static and dynamic magnetic measurements identified weak intermolecular dipolar interactions in 2, and such effects can be waived by dilution, which was noted by the detection of zero-field single molecule magnet (SMM) behaviour and hysteresis loop in a magnetically diluted sample (5). Compounds 2-4 exhibit SMM behaviours with energy barriers of 53, 32, and 45 K, respectively. To the best of our knowledge, these complexes are the first examples of pure 4f sulfonate-based SMMs.

The solubility of sodium 1-naphthalenesulfonate and sodium 2-naphthalenesulfonate in pure organic solvents of acetone, 1,4-dioxane, cyclohexanone, ethanol, ethyl acetate and isopropanol were measured by using the isothermal saturation method at temperature ranging from (278.15 to 323.15) K under 101.3 kPa. The mole fraction solubility of sodium 1-naphthalenesulfonate and sodium 2-naphthalenesulfonate in the selected pure solvents increased with the increase in temperature. The maximum mole fraction solubility of sodium 1-naphthalenesulfonate was observed in ethanol (2.767 × 10 − 3 at 323.15 K), followed by that in 1,4-dioxane (2.028 × 10 − 3 at 323.15 K), cyclohexanone (1.522 × 10 − 3 at 323.15 K), isopropanol (1.094 × 10 − 3 at 323.15 K), acetone (5.997 × 10 − 4 at 308.15 K) and ethyl acetate (3.111 × 10 − 4 at 323.15 K); For sodium 2-naphthalenesulfonate + solvents systems, the maximum mole fraction solubility was observed in ethanol (1.178 × 10 − 3 at 323.15 K), followed by that in 1,4-dioxane (1.027 × 10 − 3 at 323.15 K), ethyl acetate (6.197 × 10 − 4 at 323.15 K), cyclohexanone (3.233 × 10 − 4 at 323.15 K), isopropanol (1.058 × 10 − 4 at 323.15 K) and acetone (9.683 × 10 − 5 at 323.15 K). The measured solubility data were correlated and calculated by using the modified Apelblat equation, λh equation and NRTL model. The calculated solubilities agreed better with the experimental values by using the modified Apelblat equation than the other two models. Moreover, the mixing properties including the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration ( γ 1 ∞ ) and reduced excess enthalpy ( H 1 E , ∞ ) were calculated by NRTL model.

An easy-to-use fluorescent probe for detecting protamines was developed. Protamines are detected using the probe because of competitive interactions of polyacrylic acid modified with sodium 4-amino-1-naphthalenesulfonate (ANS-PAA) with protamines and aminated graphene oxide (GO-NH2). The ANS-PAA fluorescence was effectively quenched by the GO-NH2, the high quenching efficiency being caused by the ANS-PAA becoming non-covalently bound to the GO-NH2 surface through electrostatic interactions, forming a ANS-PAA/GO-NH2 complex. Adding protamines recovered the fluorescence of the ANS-PAA/GO-NH2 complex. This recovery was due to the positively charged protamines removing ANS-PAA from the GO-NH2 surfaces and forming ANS-PAA/protamine complexes. Displacement of GO-NH2 by protamines gave a high fluorescence recovery efficiency. Under optimal conditions, the fluorescence intensity when protamines were added was proportional to the protamine concentration over the range 0 to 6.0 μg mL−1. The detection limit was 0.4 μg mL−1. This approach offers a new quantitative method for determining protamines.

Molecular recognition based on cationic water-soluble pillar[n]arenes shows considerable advantages in their application in biological and environmental systems, such as excellent anion-binding ability and antimicrobial properties. Unique complex models are discovered in this work where a cationic water-soluble pillar[6]arene binds with disodium 1,5-naphthalenedisulfonate and disodium 2,6-naphthalenedisulfonate at the ratio of 1 : 2, which is proven by results from nuclear magnetic resonance spectroscopy, isothermal titration calorimetry, fluorescence spectroscopy experiments and transmission electron microscopy.

Aromatic sulfonated compounds and naphthalene derivatives are major chemical compounds used in the industry. Electron beam irradiation of aqueous solutions of 2-naphthalenesulfonate (90 µM) was investigated under various experimental conditions. The results obtained demonstrate that the 2-NS concentration decreased dramatically on increasing the absorbed dose in the range 0–1000 Gy. The effectiveness of the radiolytic system was demonstrably enhanced by the addition of oxidants (S 2 O 8 2− or H 2 O 2 ). 2-NS removal was higher with S 2 O 8 2− than with H 2 O 2 . For the EB, EB/H 2 O 2 , and EB/S 2 O 8 2− systems, the absorbed doses for 90% elimination of 2-NS (D 90 ) were 700, 480, and 274 Gy, respectively. 2-NS is poorly mineralized by EB but more than 35% mineralization was reached for 15 kGy when oxidants (820 µM S 2 O 8 2− or 935 µM H 2 O 2 ) were added. In all systems, the mineralization yield was markedly higher when air (i.e. dissolved oxygen increase) was introduced between successive doses. For 50% 2-NS removal, seven sulfonated transformation products were identified using LC/MS analyses. For the highest absorbed doses the sulfonate group in 2-NS was converted to sulfate ions in the radiolytic systems.

The fluorescent dye 8-anilino-1-naphthalenesulfonate (ANS) is a widely used fluorescent probe molecule for biochemistry analysis. This paper reported the fabrication of ANS/layered double hydroxide nanosheets (ANS/LDH)n ultrathin films (UTFs) via the layer-by-layer small anion assembly technique based on electrostatic interaction and two possible weak interactions: hydrogen-bond and induced electrostatic interactions between ANS and positive-charged LDH nanosheets. The obtained UTFs show a long-range-ordered periodic layered stacking structure and weak fluorescence in dry air or water, but it split into three narrow strong peaks in a weak polarity environment induced by the two-dimensional (2D) confinement effect of the LDH laminate; the fluorescence intensity increases with decreasing the solvent polarity, concomitant with the blue shift of the emission peaks, which show good sensoring reversibility. Meanwhile, the UTFs exhibit selective fluorescence enhancement to the bovine serum albumin (BSA)-like protein biomolecules, and the rate of fluorescence enhancement with the protein concentration is significantly different with the different protein aggregate states. The (ANS/LDH)n UTF has the potential to be a novel type of biological flourescence sensor material.

On the basis of a modified ion-association method, fluorescent organic nanoparticles of 8-anilino-1-naphthalenesulfonate (ANS) are synthesized in pure aqueous solution. The ANS dye is an anionic chromophore having a strongly hydrophilic sulfonate group, so the use of bulky, bis-quaternary phosphonium co-cation, that is, o-xylylenebis(triphenylphosphonium) cation (XTPP), is very effective for producing ion-based nanoparticles with a diameter of 150–250 nm. Binding of ANS with XTPP significantly modulates the intensity and peak position of the dye fluorescence, but interestingly, the emission properties are strongly influenced by post-dilution of the native dispersions. Electron microscopy and dynamic light scattering experiments reveal that, upon post-dilution, native ANS nanoparticles are etched, and the size-reduced particles are interconnected with each other to form a particle network of about ∼200 nm, resulting in a remarkable change in the dye fluorescence.

Treatment of metal complex dye wastewater has attracted growing attention due to the degradation-resistant, high cost and potential hazards of current techniques. This study reported a marine bacterium (Pseudoalteromonas sp CF10-13) with potential performance in decolorization and degradation of a metal complex dye—Naphthol Green B (NGB) at wide ranges of salinity, dye concentration and alkalinity under anaerobic conditions. It was inferred that the secretion of electron mediators in soluble extracellular metabolites by P. sp CF10-13 played important roles in NGB decolorization and degradation through extracellular electron transfer. Naphthalenesulfonate, the major structure in NGB molecule, was further degraded into low-toxic benzamide. Black stable iron–sulfur nanoparticles were formed endogenously avoiding H2S releasing, exogenous sulfur addition and metal sludge in accumulation. Accordingly, this study provided a cost-effective and eco-friendly biodegradation method to refractory NGB, further promoting the understanding of dye resources recovery.

International audience; Cyclodextrins (CDs) are the most widely used organic hosts for the inclusion of guest molecules. CDs can be readily modified through substitutions of the hydroxyl groups, and these modified CDs can have different host binding properties compared to those of parent CDs. However, only relatively few systematic studies of the effects of chemical substitution on CD binding ability have been reported thus far. In this paper, we report the study of the binding properties of five different analytically pure modified β-cyclodextrin (β-CD) hosts (substituted with alkyl and/or hydroxyalkyl groups) with 2-anilino-6-naphthalenesulfonate (2,6-ANS) as guest. Binding constants for the formation of the inclusion complex between 2,6-ANS and each CD were determined using both fluorescence spectroscopy and capillary electrophoresis. Addition of modified CDs to an aqueous solution of 2,6-ANS resulted in significant enhancement of the fluorescence intensity of 2,6-ANS, as well as a significant spectral blue shift, indicative of inclusion. Inclusion of 2,6-ANS within the CD cavity was confirmed by NMR spectroscopy. Substitution at position 3 decreased the magnitude of the binding constants, while alkyl or hydroxylalkyl substitution of the primary hydroxyl at position 6 increased the magnitude of the binding constant in all cases, in relation with increasing length of the alkyl chain linker. In addition, binding constants decreased with solvent polarity when increasing amounts of methanol were added. Structure–binding correlations for CDs based on these binding constant results are presented and discussed.

The equilibrium solubility of sodium 1-naphthalenesulfonate in binary NaCl + water, Na2SO4 + water, and C2H5OH + water solvent mixtures was measured by a steady-state method at elevated temperatures from (278.15 to 323.15) K. The results of these data were correlated by a modified Apelblat equation. The dissolution enthalpy (ΔHd) and entropy (ΔSd) of sodium 1-naphthalenesulfonate in solutions of different mole fraction were obtained.

In this work, solid–liquid equilibria (SLE) data for ternary sodium 1-naphthalenesulfonate + sodium 2-naphthalenesulfonate + water system was measured at (283.15, 303.15 and 323.15) K respectively. The diagrams for solid liquid phase of the ternary system were well-established by the measured solubility data. The solid phases formed in the studied system were determined by the method of Schreinemaker’s wet residue. Moreover, the density of equilibrium liquid phase was gained in the process. At each temperature, there are two pure solids forming. They are sodium 1-naphthalenesulfonate and sodium 2-naphthalenesulfonate in the ternary system. The solubility data for the ternary system were calculated and regressed by NRTL model, giving acceptable results for the investigated systems.

In this study, lignite char–water mixture (LCWM) was prepared with char from lignite pyrolysis at different temperatures. Sodium lignosulfonate (SL), naphthalenesulfonate formaldehyde (NSF) or the mixture of SL and NSF was used as dispersant in the preparation of LCWM. The effect of dispersant on fluidity and stability of LCWM was investigated at the fixed char loading of 60 wt.%. The results showed that the mixture of SL and NSF as dispersant can effectively decrease the apparent viscosity to less than 400 mPa s and enhance the fluidity of LCWM. The optimum dispersant content for four lignite char samples was examined and the adsorption behaviors of SL, NSF and their mixture on the char surface were also discussed. Meanwhile, the static stability of LCWM was investigated with sodium salt of carboxymethyl cellulose as stabilizer.

A naphthalenesulfonate-assimilating bacterium, Pseudomonas sp. TA-2, was found to convert 2-naphthoate to cis-1,2-dihydroxv-1,2-dihydronaphthalene-2-carboxylate (DDN2C) and cis-l,2-dihydroxy-l,2-dihydronaphthalene-3-carboxylate (DDN3C), and converted 1-naphthoate to as-l,2-dihydroxy-l,2-dihydronaphthalene-l-carboxylate (DDN1C). It was suggested that conversion of naphthoates was done by a dioxvgenase with relaxed regioselectivity.

A new capillary electrophoresis method dedicated to the analysis of neutral underivatized carbohydrates was recently developed by our group. It involved a background electrolyte composed of 98 mM NaOH and 120 mM NaCl, and direct UV detection via the formation of an absorbing intermediate in the detection window by photooxidation. This article focuses on the validation of this method for the determination of fructose, glucose, lactose, and sucrose in forensic, pharmaceutical, and beverage samples. Intermediate precisions were about 2.3% for normalized corrected peak areas and 1.8% for normalized migration times using naphthalenesulfonate as internal standard. Limits of detection varying from 5 μM for sucrose and lactose to 7 μM for glucose and 10 μM for fructose were obtained. Potential matrix effects were statistically studied for soil, cloth, plastic, cotton, red wine, and with simulated iron, calcium, and sucrose-based matrices, containing various inorganic anions and cations, sometimes at high levels. No significant matrix effect was observed. Finally, analyses of real post-explosion residues, smoke device, cough syrup, red wine, and apple juice were successfully performed.

Novel microcapsules were prepared from colloidal core–shell particles by acid dissolution of the organic core. Weakly crosslinked, monodisperse and spherical melamine-formaldehyde polycondensate particles (diameter ∼ 1 μm) were synthesized as core template and coated with multilayers of an anionic polyelectrolyte via layer-by-layer deposition technique. As polyelectrolytes, an anionic naphthalenesulfonate formaldehyde polycondensate that is a common concrete superplasticizer and thus industrially available, and cationic poly(allylamine hydrochloride) were used. Core removal was achieved by soaking the core–shell particles in aqueous hydrochloric acid at pH 1.6, resulting in hollow microcapsules consisting of the polyelectrolytes. Characterization of the template, the core–shell particles, and the microcapsules plus tracking of the layer-by-layer polyelectrolyte deposition was performed by means of zeta potential measurement and scanning electron microscopy. The microcapsules might be useful as microcontainers for cement additives. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Silver nanoparticles (AgNPs) are increasingly used in daily life for their antibacterial properties, but their low stability and high cytotoxicity hamper practical applications. In this work, sodium 1-naphthalenesulfonate-functionalized reduced graphene oxide (NA-rGO) was used as a substrate for AgNPs to produce a AgNP-NA-rGO hybrid. This hybrid showed substantially higher antibacterial activity than polyvinyl pyrrolidone (PVP)-stabilized AgNPs, and the AgNPs on NA-rGO were more stable than the AgNPs on PVP, resulting in long-term antibacterial effects. More importantly, this hybrid showed excellent water solubility and low cytotoxicity, suggesting the great potential application as sprayable reduced graphene oxide based antibacterial solutions.

Succinoglycan, an acidic exopolysaccharide, is produced by the nitrogen-fixing bacterium, Shinorhizobium meliloti. The main chain consists of a β-1,3, β-1,4, and β-1,6 linked octasaccharide subunit containing one galactose at the reducing end and seven glucose residues. Also, the repeating unit carries pyruvyl, acetyl, and succinyl modifications. The acetyl group is located at the C6 position of the third sugar residue from the reducing galactose, the succinyl group is located at the C6 position of the seventh sugar, and the pyruvyl group is linked to the eighth sugar residue through a 4,6-ketal linkage. The succinoglycan has high molecular weight (HMW) forms consisting of hundreds of octasaccharide units and low molecular weight (LMW) forms that are composed of monomers, dimers, and trimers of the octasaccharide unit. The LMW succinoglycan offers the advantages of the HMW succinoglycan for research because it is not viscous and the structure is simpler than the HMW succinoglycan. Also, the LMW succinoglycan is of particular interest, as some reports have described that it is able to restore the ability of invasion-deficient S. meliloti mutants to invade nodules. In addition to investigation of its biological activity, physico-chemical properties of the LMW succinoglycan have been studied. Monomers of succinoglycan have been isolated and investigated as chiral additives in capillary electrophoresis (CE) for the chiral separation of some flavonoids. The effect of enantioseparation is known to be dependent on the succinate moiety of the monomer structure. Also, flavonoid enantioseparations using succinoglycan monomer show that the monomer may directly interact with flavonoids produced by the host plant. However, there have been no reports on physico-chemical properties of dimers or trimers. Herein, we examine the structural properties of the dimers. The chemical structures of succinoglycan dimers are also shown in Figure 1(a). Fluorescent probes are defined as small molecules that undergo changes in one or more of their fluorescent properties as a result of hydrophobic interaction with environmental macromolecules. As representative fluorescent probes, 8-anilino-1-naphthalene sulfonate (ANS) and 6-ptoluidino-2-naphthalenesulfonate (TNS) have been used to explore the hydrophobicity of biomolecules. The chemical structures of both fluorescent probes are shown in Figure 1(b) and 1(c). In the present study, the fluorescence of ANS and TNS, respectively, in an aqueous solution was investigated under the presence of succinoglycan dimers (D1, D2, D3, and D4), and the hydrophobic character of the dimers was analyzed. Based on double reciprocal plots of the fluorescence increments depending on the dimer concentration, the association constants could be estimated. The results indicate that association constants of ANS and TNS, respectively, with D2 are the largest among the 4 types of

The extraction of copper, nickel, cobalt, zinc, and iron chlorides by the solutions of trioctylmethylammonium dinonyl naphthalenesulfonate in toluene depending on the acidity of aqueous phase was studied. In the range of relatively high acidity (from 3 to 1 M HCl), an increase in the DM values is observed with a growth in the concentration of hydrogen ions in aqueous phase; that corresponds to the principles of the binary extraction of chloro complex metal-containing acids. With a decrease in the acidity of aqueous phase, an increase in the distribution coefficients of metals is observed due to the change in the extraction mechanism and increase in the fraction of the complexes extracted as metal dinonyl naphthalenesulfonates. In the acidic range, the extractability of metals is mainly determined by the stability of complex metal-containing anions and qualitatively corresponds to the following order: Fe(III) > Cu(II) > Co(II) > Ni(II).

A novel technology of nitrogen-doped TiO2 with visible light photocatalysis combining electrodialysis was proposed for simultaneous oxidization of naphthalenesulfonate (NS)/reduction of hexavalent chromium (Cr(VI)) by electron–hole pairs. N-TiO2 nanocrystal was prepared by calcinating the mixture of Degussa P-25 TiO2 and NH4Cl at temperatures of 400 °C under airtight condition, and the application of cation-exchange membrane was used to enhance the efficiency for prevention of the reoxidation of reductive chromium with the electron–hole pairs. The results showed, when pH is lower than 6.8, the electrostatic attractions were happened for the positive charge Ti-OH 2 + , negatively charged Cr(VI) and NS, resulting in higher efficiency. Only 20.2% of Cr(VI) was removed when NS was absence for pH 3 with N-TiO2 of 1.0 g/L, but complete Cr(VI) removal was observed for initial NS concentration up to 50 mg/L, indicating NS plays the role of hole scavenger in the system. The generation of sulfate (as sulfur) is equivalent to the degradation of NS (as sulfur), representing the yield of sulfate is an excellent indicator for NS removal. Moreover, incomplete NS decomposition contributes to the occurrence of intermediates, including propenoic acid, isocrotonic acid, formic acid, and formaldehyde, as identified by GC/MS analysis.

For investigation of influence of reactive oxygen species on biological systems the peculiarities of light scattering and fluorescence spectra of aqueous solutions in the presence of photoactive additions of acetone (5 x 10(-4) - 30) and anionic probe ANS (5 microg/l-10 mg/l) have been considered. In water and diluted aqueous acetone and ANS solutions, long-term spontaneous variations in parameters of light scattering and fluorescence spectra have been detected. It has been found that the spectral parameters and the character of ANS influence changed drastically at acetone concentrations of approximately 0.1%, approximately (0.2-0.3)%, and approximately 0.8%. The results can be explained by rearrangement of solvent structure in the surrounding of admixture molecules, photochemical processes with the participation of acetone and reactive oxygen species, as well secondary reactions with their involvement in gas-vapor and acetone bubbles.

The molecular binding behavior of two bis(β-cyclodextrin (CD))s, that is, 4,4′-diaminodiphenylsulfone-bridged bis(β-CD) 2 and 4,4′-diaminodiphenyldisulfide-bridged bis(β-CD) 3 with some representative organic dyes, i.e., acridine red (AR), neutral red (NR), ammonium 8-anilino-1-naphthalenesulfonate (ANS), sodium 2-(p-toluidinyl)naphthalenesulfonate (TNS), rhodamine B (RhB), and brilliant green (BG), has been investigated at 25 °C in phosphate buffer (pH 7.20) by ultraviolet, fluorescence and 2D NMR spectroscopy. The fluorescence of ANS, TNS, AR, and NR are enhanced, whereas that of RhB is quenched, by inclusion complexation with both host compounds. The results obtained show bridged bis(β-CD)s 2 and 3 with dye guests give higher complex stability constants (K S) than those of the native β-CD 1, through cooperative binding of two hydrophobic CD cavities with one guest. In addition, the K S values of all guests with host 3 are much larger than those with 2 except for NR as guest. The 2D 1H NOESY spectrum of host 3 and RhB was acquired to confirm the cooperative binding mode. The molecular binding ability of dyes by hosts 1–3 are discussed from the viewpoint of the size and shape-fitting relationship between host and guest.

A conformational study of 2-anilino-6-naphthalenesulfonate (2,6-ANS), a widely used “fluorescence probe” compound, was carried out using classical potential energy functions (the CAMSEQ method) with a 2-dimensional, torsional correction term. A variety of solvent environments was considered, including aqueous, 1 -octanol, ethanol, and methanol in addition to the isolated molecule. The results agree with crystal data for a closely related compound, but differ from a previous theoretical study. The calculated equilibrium geometry appears to be relatively insensitive to solvent environment.

The acid-induced isomerization (the N-F transition) and expansion of bovine plasma albumin--1-anilino-8-naphthalenesulfonate complex, BPA-ANS1.0 complex (molar ratio of added ANS to BPA = 1.0) were studied by measuring fluorescence and induced CD spectra of ANS. Decrease in the reciprocal of fluorescence polarization, increase in fluorescence intensity and blue shift of fluorescence of ANS in BPA-ANS1.0 complex were correlated with the initial part of the N-F transition and/or the N-F1 transition. Induced CD spectra of ANS showed positive bands at 250-258 and 320-350 nm and one negative band at 280 nm. Most of changes (decreases) in -[theta]280 were also correlated with the initial part of the N-F transition and/or the N-F1 transition. Changes in fluorescence parameters and induced CD spectra of ANS (-[theta]280) might indicate the conformational changes around a strong ANS binding site in the N-terminal domain (Reed et al. (1975), JonasWeber (1970) and BrownShockley (1982].

The effect of humates isolated from peat on the state in solution of the leuco acid of Vat Brilliant Green C dye was examined spectrophotometrically and compared with the effect of dispersants traditionally used in textile-chemical processes: disodium methylenebis(naphthalenesulfonate) and triethanolamine.

The solvatochromic fluorescent probe 8-anilino-1-naphthalenesulfonate (ANS) has been used to study the hydrophobicity and conformational dynamics of lecithin:cholesterol acyltransferase (LCAT). The ANS to LCAT binding constant was estimated from titrations with ANS, keeping a constant concentration of LCAT (2 microM). Apparent binding constant was found to be dependent on the excitation. For the direct excitation of ANS at 375 nm the binding constant was 4.7 microM(-1) and for UV excitation at 295 nm was 3.2 microM(-1). In the later case, not only ANS but also tryptophan (Trp) residues of LCAT is being excited. Fluorescence spectra and intensity decays show an efficient energy transfer from tryptophan residues to ANS. The apparent distance from Trp donor to ANS acceptor, estimated from the changes in donor lifetime was about 3 nm and depends on the ANS concentration. Steady-state and time-resolved fluorescence emission and anisotropies have been characterized. The lifetime of ANS bound to LCAT was above 16 ns which is characteristic for it being in a hydrophobic environment. The ANS labeled LCAT fluorescence anisotropy decay revealed the correlation time of 42 ns with a weak residual motion of 2.8 ns. These characteristics of ANS labeled LCAT fluorescence show that ANS is an excellent probe to study conformational changes of LCAT protein and its interactions with other macromolecules.

A novel anthraquinone diamino-bridged bis(β-cyclodextrin) 2 was synthesized. The inclusion complexation behaviors of the native β-cyclodextrin 1 and the novel bis(β-cyclodextrin) 2 with guests, such as acridine red (AR), neutral red (NR), ammonium 8-anilino-1-naphthalenesulfonate (ANS), sodium 2-(p-toluidinyl) naphthalenesulfonate (TNS) and rhodamine B (RhB) were investigation by fluorescence, circular dichroism and 2D NMR spectroscopy. The spectral titrations were performed in phosphate buffer (pH 7.20) at 25 o C to give the complex stability constants (Ks) and Gibbs free energy changes (−ΔG 0 ) for the stoichiometric 1:1 inclusion complexation of host 1 and 2 with guests. The results indicated that the novel bis(β-cyclodextrin) 2 greatly enhanced the original binding affinity of the native β-cyclodextrin 1. Typically, bis(β-cyclodextrin) 2 showed the highest binding constant towards ANS up to 34.8 times higher than that of 1. The 2D NMR spectra of bis(β-cyclodextrin) 2 with RhB and TNS were performed to confirm the binding mode. The increased binding affinity and molecular selectivity of guests by bis(β-cyclodextrin) 2 were discussed from the viewpoint of the size/shape-fit concept and multipoint recognition mechanism.

In this paper, modification of polyimide hollow fiber membrane was carried out by introduction of tetrabutylammonium naphthalenesulfonate (BAN) into the membrane matrix. Permeation performance of modified hollow fibers was investigated helps to compressed air dehydration ability across the membrane. The experimental results showed that water sorption and water vapor permeability obviously increase with increase on BAN content in modified membranes, and air dehydration performance was improved by increasing BAN in membrane and ratio of sweeping gas. Moreover, operational pressure and feed flux also impose on important effect on compressed air dehydration capability.

Novel β-cyclodextrin (β-CD) dimers with aromatic diamine linkers, 1,3-(aminomethyl)-benzylamine-bridged bis(6-amino-6-deoxy-β-CD) (2), 4,4′-diaminodiphenylmethano-bridged bis(6-amino-6-deoxy-β-CD) (3), and 4,4′- ethylenedianiline-bridged bis(6-amino-6-deoxy-β-CD) (4), were synthesized. The inclusion complexation behaviors of these compounds, together with 4,4′-aminophenyl ethyl-bridged bis(6-amino-6-deoxy-β-CD) (5), with substrates such as acridine red (AR), neutral red (NR), ammonium 8-anilino-1-naphthalenesulfonate (ANS), sodium 2-(p-toluidinyl) naphthalenesulfonate (TNS), rhodamine B (RhB), and brilliant green (BG), were investigated by ultraviolet, fluorescence, circular dichroism, and 2D NMR spectroscopy. The results indicated that the two linked CD units cooperatively bound to a guest, and the molecular binding affinity toward substrates, especially curved guest ANS and linear guests such as NR and AR, was increased. The linker length between two CD units played a crucial role in the molecular recognition of the hosts with guest dyes. The binding constants of the hosts for AR, TNS, ANS, and RhB decreased with increasing linker length in hosts 2-4. Moreover, structurally similar hosts 3 and 5 exhibited very different binding behavior for the guests. Host 5 showed much higher Ks values toward positively charged guests and lower Ks toward negatively charged guests than host 3. The 2D NMR spectra of hosts 3 and 5 with RhB were acquired to understand the binding difference between 3 and 5. The molecular binding ability and selectivity of model substrates by these hosts were sufficiently investigated to reveal not only the cooperative contributions of the linker group and CD cavities upon inclusion complexation with dye guest molecules, but also the controlling factors for the molecular selective binding. Copyright © 2008 John Wiley & Sons, Ltd.

The effect of CaCl 2 on aggregation and conformational changes of tropical tilapia ( Oreochromis niloticus ) actomyosin incubated at 4 and 40 °C was investigated. Aggregation of tilapia actomyosin incubated at 40 °C for 30 min increased with addition of 10–100 mM CaCl 2 . Formation of higher molecular weight protein (HMP) at 40 °C was enhanced by addition of >10 mM Ca 2+ ion, but suppressed by 2 mM N-ethylmaleimide (NEM) and 1 mM phenylmethnesulfonyl fluoride (PMSF), suggesting the involvement of endogenous transglutaminase (TGase). Moreover, addition of 10–100 mM CaCl 2 destabilized actomyosin as evident by an increase in aniline naphthalenesulfonate surface hydrophobicity (S 0 -ANS) and loss of α-helical structure at 40 °C. However, CaCl 2 only increased S 0 -ANS of actomyosin incubated at 4 °C without disturbing its secondary structure. Both e-(γ-glutamyl)lysine isopeptide bonds and hydrophobic interactions appeared to be involved in HMP aggregates formed at 40 °C. Breaking force and deformation of actomyosin gels incubated at 40 °C for 30 min increased with added CaCl 2 level and reached the maximum at 100 mM CaCl 2 , corresponding to an increased intensity of HMP observed on 5% SDS-PAGE. Ca 2+ improved gelation during setting at 40 °C by not only activating endogenous TGase but also promoting hydrophobic interactions among unfolded actomyosin. Setting was also induced to a lesser extent at 4 °C in the presence of >10 mM CaCl 2 .

Acid-induced unfolding of horse apomyoglobin is studied with fluorescence of tryptophan residues and extrinsic probes 8-anilino-1-naphthalenesulfonate (ANS) and pyrene. Two-dimensional statistical correlation coefficient analysis of tryptophan, ANS and pyrene fluorescence reveals that apomyoglobin unfolds in two steps via a folding intermediate. Both tryptophan and ANS fluorescence show microenvironment-sensitive emission maximum and fluorescence intensity. Hetero-spectral 2D correlation analysis reveals that the “red” tryptophan fluorescence correlates with the “red” ANS fluorescence, and the “blue” correlates with the “blue” in the acid-induced unfolding process. Correlation curves are established between the hydrophobicity of the probe-binding site(s) as disclosed by ANS and pyrene fluorescence and the folding extent of apomyoglobin as indicated by tryptophan fluorescence. Two anion-induced refolding intermediates of apomyoglobin: Cl − -induced A-1, and trichloroacetate (TCA)-induced I-2 do not follow the correlation trajectory in the acid-induced unfolding. This suggests that the two anion-induced intermediates do not belong to the low-salt acid-unfolding pathway of apomyoglobin.

Sphingomonas xenophagaBN6 degrades various (substituted) naphthalenesulfonates to the corresponding (substituted) salicylates. A gene cluster was identified on the plasmid pBN6 which coded for several enzymes participating in the degradative pathway for naphthalenesulfonates. A DNA fragment of 16 915 bp was sequenced which contained 17 ORFs. The genes encoding the 1,2-dihydroxynaphthalene dioxygenase, 2-hydroxychromene-2-carboxylate isomerase, and 2′-hydroxybenzalpyruvate aldolase of the naphthalenesulfonate pathway were identified on the DNA fragment and the encoded proteins heterologously expressed inEscherichia coli. Also, the genes encoding the ferredoxin and ferredoxin reductase of a multi-component, ring-hydroxylating naphthalenesulfonate dioxygenase were identified by insertional inactivation. The identified genes generally demonstrated the highest degree of homology to enzymes encoded by the phenanthrene-degrading organismSphingomonassp. P2, or the megaplasmid pNL1 of the naphthalene- and biphenyl-degrading strainSphingomonas aromaticivoransF199. The genes ofS. xenophagaBN6 participating in the degradation of naphthalenesulfonates also shared the same organization in three different transcriptional units as the genes involved in the degradation of naphthalene, biphenyl, and phenanthrene previously found inSphingomonassp. P2 andS. aromaticivoransF199. The genes were flanked inS. xenophagaBN6 by ORFs which specify proteins that show the highest homologies to proteins of mobile genetic elements.

We demonstrate two-dimensional heterocorrelation analysis between spectrally resolved and temporally resolved fluorescence to investigate the decay dynamics of the 8-anilino-1-naphthalenesulfonate- (ANS-) apomyoglobin complex. The dynamic changes of the lifetime components are disclosed across the emission spectrum with an external pH-perturbation. Two different fluorescence lifetime schemes of the ANS-apomyoglobin complex are revealed. From pH 8.5 to 4.5, the transition of protein conformation from the native state to the folding intermediate, a short lifetime component is found to correlate with a short-wavelength emission whose population diminishes with decreasing pH. The lifetime components reflect the excited-state populations of the nascent and the charge-transfer species. From pH 4.2 to 1.0, the transition from the folding intermediate to the acid-unfolded state, the short lifetime is responsible for a long-wavelength emission and the fraction of this component increases when the solution becomes more acidic. In this pH range, the decay components reflect the ground-state populations of microenvironments. The relative decay dynamics across the emission spectrum are revealed without collecting decays at each wavelength. More importantly, these conclusions are reached without the necessity of statistical fitting of the decay data with an a priori decay model.

Heat treatment of bovine beta-lactoglobulin B (beta-LG) causes it to partially unfold and aggregate via hydrophobic association and intra- and interprotein disulfide bonds. The first stage, which involves a "loosening" of the native structure, is influenced by the environmental conditions, such as pressure, pH, and added solutes. In the present study, four potential beta-LG ligands [palmitate, sodium dodecyl sulfate (SDS), 8-anilino-1-naphthalenesulfonate (ANS), and all-trans-retinol (retinol)] were added to beta-LG solutions prior to heat treatment for 12 min at temperatures between 40 and 93 degrees C. The extent of the changes in secondary and tertiary structures, unfolding, and aggregation at 20 degrees C were determined by circular dichroism, fluorescence, and alkaline- and SDS-polyacrylamide gel electrophoresis (PAGE). Both palmitate and SDS stabilized the native structure of beta-LG against heat-induced structural flexibility, subsequent unfolding, and denaturation. Retinol was less effective, probably because of its lower affinity for the calyx-binding site, and ANS did not stabilize beta-LG, suggesting that ANS did not bind strongly in the calyx. It was also noted that holding a beta-LG solution with added SDS or ANS promoted the formation of a hydrophobically associated non-native dimer.

Cyclic voltammetric studies of poly(vinylferrocene), PVF, in aqueous sodium perchlorate, sodium p-toluenesulfonate, and sodium naphthalenesulfonate solutions revealed unexpected history effects. The films contain redox sites in two local environments. One type of ferrocene site is in a compact, unsolvated environment; it undergoes redox switching in NaClO4 with only the transfer of counter ions. The other type of ferrocene site is in a more diffuse environment; it undergoes redox switching with the transfer of perchlorate counter ion and water. Only the latter sites can accommodate large anions (toluenesulfonate or naphthalenesulfonate), and therefore undergo redox switching in such media. Upon multiple redox cycling, these large anions get progressively locked into the structure, thereby blocking the diffuse sites. Upon transfer back to NaClO4 solution, only the “compact” sites are able to undergo redox switching.

Inhibition of angiogenesis-promoting factors such as fibroblast growth factors is considered to be a potential procedure for inhibiting solid tumor growth. Although several peptide-based inhibitors are currently under study, the development of antiangiogenic compounds of small molecular size is a pharmacological goal of considerable interest. We have already shown that certain naphthalene sulfonates constitute minimal functional substitutes of the antiangiogenic compounds of the suramin and suradista family. Using those data as a lead, we have carried out a rational search for new angiogenesis inhibitors that could provide new pharmacological insights for the development of antiangiogenic treatments. The results of the study strongly underline the relevance of the stereochemistry for an efficient inhibition of acidic fibroblast growth factor mitogenic activity by the naphthalene sulfonate family and allow us to formulate rules to aid in searching for new inhibitors and pharmaceutical developments. To provide further leads for such developments and acquire a detailed insight into the basis of the inhibitory activity of the naphthalene sulfonate derivatives, we solved the three-dimensional structure of acidic fibroblast growth factor complexed to 5-amino-2-naphthalenesulfonate, the most pharmacologically promising of the identified inhibitors. The structure shows that binding of this compound would hamper the interaction of acidic fibroblast growth factor with the different components of the cell membrane mitogenesis-triggering complex.

Per(3-deoxy)-γ-cyclomannin has been efficiently synthesized by a three-step procedure starting from natural γ-cyclodextrin, and proved to be capable of binding naphthalenesulfonate in aqueous solution and solubilizing C 60 in water. For the first time it was spectrally evidenced that a non-glucose cyclooligosaccharide did form inclusion complexes with conventional organic guest molecules.

This study systematically investigates the optimal conditions for analyzing the positional isomers of multi-charged naphthalenesulfonate compounds by cyclodextrin-mediated capillary electrophoresis (CE). Specifically, this work employs large-volume sample injection with the electrode polarity switching technique. The most effective separation and sample stacking conditions were 15 mM borate buffer with a mixture of beta- and gamma-cyclodextrin (concentration ratio 3:7 mM) at pH 9.2, and the sample hydrodynamic injection of up to 60 s at 3 p.s.i. (around 1.8 microl, and 1 p.s.i. = 6.9 kPa). Significantly selective and sensitive improvements were observed and a more than 100-fold enrichment was achieved (based on peak area). The reproducibility of migration time and quantitative results of stacking CE can be improved by using an internal standard. The quantitation limits of these naphthalenesulfonate isomers, based on a signal-to-noise ratio above 10, can be about 4 microg/l with UV detection. This method was successfully applied to determine the trace amount of naphthalenesulfonate isomers in a spiked drinking water sample.

We investigated the phase behavior of cationic tetradecyldimethylhydroxylammonium chloride (C14DMAOH·Cl) (a fixed surfactant concentration, 20 mM) in the presence of sodium 2-naphthalenesulfonate (SNphS) as a function of the molar ratios β (= SNphS/C14DMAOH·Cl) by turbidity, viscosity, dye solubilization, and polarizing microscopy. The C14DMAOH·Cl/SNphS system formed aggregates with a lower curvature than cetyltrimethylammonium bromide (C16TAB)/aromatic counterion systems, despite the shorter alkyl chain. Addition of SNphS into the C14DMAOH·Cl solution at 25 °C produced precipitates of solid crystals above β ∼ 0.5, in contrast with long fibrous micelles of many other cationic micelle−aromatic counterion pairs. The crystalline solids (tetradecyldimethylhydroxylammonium naphthalenesulfonate, C14DMAOH·NphS) at 20 mM concentration were transformed into the lamellar liquid crystalline phase dispersion (lamellar droplets) above 54 °C. The lamellar phase was not spontaneously converted into vesicles upon dilutio...

This work presents a method to separate polar naphthalenesulfonate (NS) isomers by capillary zone electrophoresis (CZE) with ultraviolet detection in industrial effluents and river water samples. The method involves extraction of samples by a polystyrene-divinylbenzene copolymer (PS-DVB) solid-phase extraction (SPE) cartridge. The most effective CZE separation conditions were obtained in 20 mM borate buffer with 30% acetonitrile at pH 9.0 and 30 °C. The method proposed herein provides a high precision and sensitivity for NS isomers, to quantitation at ≤ 1.0 μg/L in 200 mL of the water samples. Recovery of the NS isomers in spiked water samples ranged from 73% to 87% while RSD ranging from 5.6 to 9.7%. The analysis of industrial effluents and river water samples was performed and naphthalene-2-sulfonate was found as a major pollutant. The difficulties in quantitating and identifying analytes in complex environmental samples can be resolved by using an internal standard response factor to calculate concentrations and relative migration times for peak confirmation.