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A method has been explored for assessing hydrophobic polypeptides in beer by measuring fluorescence developed upon interaction of the proteins with 1-anilino-8-naphthalenesulfonate. The method was initially applied to three separate purified proteins (bovine serum albumin, cytochrome c and catalase) and different response patterns were observed, suggesting that a simple picture would not be obtained with a complex polypeptide mixture such as beer. Furthermore substantial interference, including a high level of background fluorescence, was caused by beer components, especially in ales. Use of the method, after reducing interference by dilution or dialysis of the beer, does not appear to confer any additional value over the direct measurement of total protein in beer using Coomassie Blue-binding methods.

Addition of 8-anilino-1-naphthalenesulfonate (ANS) to acid-denatured pectate lyase C (pelC) leads to a large increase in the fluorescence quantum yield near 480 nm. The conventional interpretation of such an observation is that the ANS is binding to a partially folded intermediate such as a molten globule. Far-ultraviolet circular dichroism demonstrates that the enhanced fluorescence results from the induction of a partially folded protein species that adopts a large fraction of native-like secondary structure on binding ANS. Thus, ANS does not act as a probe to detect a partially folded species, but induces such a species. Near-ultraviolet circular dichroism suggests that ANS is bound to the protein in a specific conformation. The mechanism of ANS binding and structure induction was probed. The interaction of acid-unfolded pelC with several ANS analogs was investigated. The results strongly indicate that the combined effects of hydrophobic and electrostatic interactions account for the relatively high binding affinity of ANS for acid-unfolded pelC. These results demonstrate the need for caution in interpreting enhancement of ANS fluorescence as evidence for the presence of molten globule or other partially folded protein intermediates.

The importance of possible electrostatic effects in the complexation of cyclodextrins has been investigated. The complexation features of the anionic guest molecule, 2-(p-toluidinyl)naphthalene-6-sulfonate (TNS), with the positively charged cyclodextrin, 6-deoxy-6-amino-β-cyclodextrin (NH3+CD), and with the neutral β-cyclodextrin (β-CD) were compared. Although TNS is a widely used fluorescent probe for the studies of complexation with cyclodextrins, its behavior is still not completely understood. In this paper we show that the complexation of TNS with β-CD involves the simultaneous formation of two different 1:1 complexes, resulting from inclusion of the toluidin moiety or the naphthalenesulfonate moiety in a cyclodextrin unit, and a 1:2 complex, which is due to the complexation of the two aromatic moieties of TNS with two cyclodextrin molecules. In the complexation of TNS with NH3+CD, the same species and equilibria are present, although significant structural differences of their complexes and variatio...

Four nickle(II) 1,5-naphthalenedisulfonate (1,5nds) complexes, namely [Ni(H2O)6] (1,5nds) (1), trans-[Ni(en)2(H2O)2](1,5nds)·2H2O (2), [Ni(tren)(H2O)2](1,5nds)·H2O (3), and [Ni(dien)2](1,5nds)·2H2O (4), where en = ethylenediamine, tren = tris(2-aminoethyl)amine, and dien = diethylenetriamine, have been synthesized and structurally characterized. Compound 1 crystallizes in space group P21/c, with a = 13.200(2) A, b = 6.6197(10) A, c = 9.6001(14) A, and β = 92.005(3)° compound 2 crystallizes in space group C2/c, with a = 15.698(2) A, b = 13.006(2) A, c = 12.845(2) A, and β = 119.262(4) A compound 3 crystallizes in space group P $$\overline 1$$ , with a = 8.8971(10) A, b = 11.5440(13) A, c = 11.9169(14) A, α = 77.254(2)°, β = 74.079(2)°, and γ = 82.162(2)° compound 4 crystallizes in space group P21/c, with a = 10.3600(13) A, b = 12.5650(16) A, c = 9.9853(12) A, and β = 103.599(2)°. Compound 1 crystallizes in a typical inorganic–organic layered structure adopted by metal naphthalenesulfonate, while compounds 2–4 crystallize in a hybrid inorganic–organic pattern. Unlike their Cu2+ analogue, the sulfonate does not coordinate directly to Ni2+. The hydrogen bonds formed between sulfonate and water molecules are the predominant packing forces for all structures. The inherited inversion center of the 1,5nds anion is carried into the crystal structure and results in centrosymmetric crystallization of all compounds.

Benzene- and naphthalenesulfonates (BS, NS) are xenobiotic, highly water-soluble chemical compounds that are used for the production of many consumer products such as fluorescent whitening agents, dyes, or concrete plasticizers, and for various applications in industrial processes. They are mainly introduced into ambient waters by industrial or municipal wastewater directly or following municipal sewage treatment. In order to characterize an additional pathway for BS and NS into the environment, leachates and groundwater samples collected from the pollution plumes of four Swiss landfills were investigated. The samples were analyzed using ion-pair liquid chromatography with UV absorption and fluorescence detection. Liquid chromatography coupled to mass spectrometry was performed for the selective identification of aromatic monosulfonates. The results show that landfill sites are point sources for BS and NS in the aquatic environment. BS and NS were measured in the leachates at a wide concentration range from a few μg l−1 up to several mg l−1, depending on the composition of the deposited material. Their contribution to the leachate DOC was from below 1‰ up to around 30%. BS and NS were also found in groundwater samples contaminated by percolating leachates. The concentrations, which contributed less than 1‰ to the groundwater DOC, ranged from a few ng l−1 to several μg l−1.

Two trans-o-hydroxybenzylidenepyruvate hydratase-aldolases named tHBP HA A and tHBP HA B were purified from a cell-free extract of naphthalenesulfonate-assimilating Sphingomonas paucimobilis (formerly Pseudomonas sp.) TA-2 to an electrophoretically homogeneous state by successive column chromatographies on DEAE-cellulose, DEAE-Toyopearl 650M, Sephacryl S-100, Hydroxyapatite, and Mono Q. These enzymes were similar to each other in molecular mass (ca. 37 kDa on SDS-PAGE, ca. 110 kDa on ultracentrifugation), thermal stability (

Cyclodextrins (CD's) were visualized by postcolumn mixing with 2-p-toluidinylnaphthalene sulfonate (TNS) in liquid chromatography. The indirect detection is based on fluorescence enhancement due to the formation of an inclusion complex between TNS and CD's. β-CD gave larger signal intensity than α- and γ-CD. Different selectivities were observed for alkyl-bonded silica stationary phases with different chain length.

This paper presents a protocol for the determination of a class of polar, ionic and highly water-soluble organic pollutants: benzene- and naphthalenesulfonic acids, compounds widely used in chemical, pharmaceutical, tannery, paper and textile industries. This protocol involves the use of a solid-phase extraction (SPE) followed by ion-pair chromatography-electrospray-mass spectrometry (IPC-ESI-MS). In this work two polymeric solid-phase extraction cartridges (Isolute ENV+ and Lichrolut EN) were compared, with the more effective being Isolute ENV+ sorbent. Recoveries and breakthrough volumes were calculated by loading volumes of 150, 200 and 300 ml of spiked ground water through the SPE columns. To enhance the effectiveness of the methodology, 1 ml of water containing 5 mM TEA was added before eluting with methanol. Average recoveries ranging from 70 to 100% were obtained for a variety of 13 analytes (only two naphthalenesulfonate compounds had recoveries below 50%.). Determination of benzene- and naphthalenesulfonates was accomplished by ion-pair chromatography-fluorescence detection (IPC-FLD). The ESI-MS parameters were optimized to achieve maximum sensitivity. [M–H]− ion was the base peak using low energies (fragmentor voltage: 80 V). Significant fragmentation of the quasi-molecular [M–H]− ion occurs at higher fragmentor voltages, leading to [M–SO2H]−, [M–SO3H]− and [SO3]− as diagnostic ions, but with some sensitivity losses (more than two orders of magnitude when 150 V are applied as fragmentor voltage). Collision-induced dissociation (CID) of the parent ions for the benzene- and naphthalenesulfonates studied gave the [SO3]− fragment ion common to sulfonated compounds, it has been shown to be characteristic of aromatic sulfonated compounds and could be used as a diagnostic tool to indicate the presence of these compounds. Limits of detection (signal-to-noise ratio = 3) ranging from 0.03 pg to 0.05 ng, were achieved when 150 ml of ground water were processed and quantified by IPC-FLD. In IPC-ESI-MS, time-scheduled SIM mode with post-column addition of 0.2 m min−1 of methanol was used. LODs range from 0.6 pg to 0.13 ng. In summary, with the development of a methodology based on SPE followed by IPC-ESI-MS, good sensitivity, structural information and unequivocal identification can be achieved. This protocol was applied to the analysis of surface waters, untreated industrial waste waters and wastewater treatment works effluents and influents. In the case of tannery effluent samples, isomers of naphthalenesulfonic acid were found as major pollutants in concentrations up to 0.8 and 1.0 mg l−1, for 1-naphthalenesulfonate and 2-naphthalenesulfonate, respectively. The main contaminants in wastewater treatment work samples were 2,6-naphthalenedisulfonate, 1-hydroxy-3,6-naphthalenedisulfonate, 3-nitrobenzenesulfonate, 1-naphthalenesulfonate and 2-naphthalenesulfonate, with levels of ug/l.

In aqueous and aqueous D-glucose solutions, 6-anilino-2-naphthalenesulfonate (2,6-ANS) and 8-anilino-1-naphthalenesulfonate (1,8-ANS) form 1:1 inclusion complexes with β-CD. The molecular volume of 2,6-ANS bound to the β-CD cavity has been evaluated to be 4.7 nm3 from the viscosity dependence (Perrin plot) of the 2,6-ANS fluorescence polarization. This value indicates that 2,6-ANS incorporated into the β-CD cavity rotates as the inclusion complex on a fluorescence lifetime scale. The molecular volume of 2,6-ANS in solution without β-CD has been evaluated to be 0.88 nm3, which provides additional evidence for the whole rotation of the β-CD–2,6-ANS inclusion complex. The molecular volume of 1,8-ANS bound to the β-CD has been evaluated to be 2.7 nm3, which is comparable to the calculated molecular volume (1.9 nm3) of β-CD, indicating that 1,8-ANS most likely rotates as the inclusion complex. The fact that the molecular volume of the 1,8-ANS inclusion complex is smaller than that of the 2,6-ANS inclusion comp...

A series of novel bis(β-cyclodextrin)s connected by organoselenium linkers, i.e., 6,6‘-trimethylenediseleno-bridged bis(β-cyclodextrin) (2), 2,2‘-trimethylenediseleno-bridged bis(β-cyclodextrin) (3), 6,6‘-o-phenylenediseleno-bridged bis(β-cyclodextrin) (4), and the corresponding platinum(IV) complexes (5−7) were synthesized from β-cyclodextrin (1). The inclusion complexation behavior of 1−7 with some fluorescent dyes, i.e., ammonium 8-anilino-1-naphthalenesulfonate, sodium 2-(p-toluidinyl)naphthalenesulfonate, Methyl Orange, and Mordant Orange 1, was investigated in aqueous phosphate buffer solution (pH 7.20) at 25 °C by fluorescence and circular dichroism spectrometry, as well as fluorescence lifetime measurements. The spectrofluorometric and spectropolarimetric titrations gave the complex stability constant (KS) and Gibbs free energy change (ΔG°) for the stoichiometric 1:1 inclusion complexation of 1−7 with the fluorescent dyes. The bis(β-cyclodextrin)s 2−4 showed higher affinities toward these guests t...

The excited-state proton transfer from 4-hydroxy-1-naphthalenesulfonate to urea has been studied in methanol at 25 °C. The decay of the acidic form is single-exponential for all urea concentrations...

A 2-hydroxychromene-2-carboxylate isomerase was purified from a cell-free extract of naphthalenesulfonate-assimilating Pseudomonas sp. TA-2 to an electrophoretically homogeneous state by successive column chromatography on DEAE-cellulose, DEAE-Toyopearl 650M, Sephadex G-75, Hydroxyapatite, and Mono Q. The enzyme had a molecular mass of 25 and 27 kDa as estimated by SDS-PAGE and Superdex 200, respectively. Its N-terminal 30 amino acid sequence had high homology with the deduced amino acid sequences of the 2HC2CA isomerase of nahD (a gene of naphthalene metabolism), pahD (a gene of naphthalene and phenanthrene metabolism), and doxJ (a gene of dibenzothiophene metabolism). The enzymatic product was a trans isomer. The isomerase activity was inhibited in the presence of monoiodoacetate or Hg2+, but not by preincubation with monoiodoacetate or N-ethylmaleimide. GSH functioned as a cofactor and activated the enzyme at above 0.15 mM.

The ion-association properties of monovalent and divalent naphtholsulfonate ions were investigated with tetrabutylammonium ion (TBA(+)) as a pairing ion in an aqueous solution. The ion-association constants were obtained by analyzing the change in the electrophoretic mobility of naphtholsulfonate ions in the presence of TBA+ by capillary zone electrophoresis; also, the contribution of a hydroxyl group to the ion associability of monovalent and divalent naphtholsulfonate ions, as well as the electrophoretic mobility of the ions, was investigated. The obtained ion-association constants indicate that the positional isomers possessing anionic groups at the β-position of the naphthalene ring are more associable with TBA(+) than those at the α-position, and that the ion associability of the divalent naphtholsulfonates is larger than those of the monovalent ones, except for 1-naphthol-2-sulfonate. The abnormal associability of 1-naphthol-2-sulfonate can be explained by a synergistic increase in the hydrophilicity of the divalent ion. The difference in the ion associability between the monovalent and divalent naphtholsulfonates, 0.16 in log unit on the average, was smaller than that between the naphthalenesulfonate and naphthalenedisulfonate ions, 0.30 log unit on the average. The electrophoretic mobility of the naphtholsulfonate ions obtained in the absence of TBA(+) is compared with each other, and the contribution of the hydroxyl group is discussed on the basis of the hydration behavior of the naphtholsulfonates.

The separation of naphthalenesulfonate (NS) isomers has been successfully performed by capillary zone electrophoresis using macrocyclic polyamines, such as [9]aneN3 and [14]aneN4, as an additive to the running solution. Although group separation between naphthalenemonosulfonates (mono-NSs) and naphthalenedisulfonates (di-NSs) was achieved, the separation between mono-NS isomers, 1-NS and 2-NS, and the separation among di-NS isomers, 1,5-NS, 1,6-NS, 2,6-NS and 2,7-NS, could not be achieved using a hydrochloric acid solution (pH 2.0) as the running solution. The addition of [14]aneN4 to the running solution (pH 2.0) gave good separation, not only between mono-NSs and di-NSs but also among their NS isomers. The sequence of elution time increased in the order 2,6-NS < 2,7-NS < 1,6-NS < 1,5-NS < 2-NS < 1-NS. The sequence of elution time indicates that the interaction of the NSs with [14]aneN4 increases in the order 2,6-NS < 2,7-NS < 1,6-NS < 1,5-NS for the di-NS isomers and 2-NS < 1-NS for the mono-NS isomers. A similar sequence of elution time was obtained when [9]aneN3 was used as the additive, although the separations between the 1,5- and 1,6-NS isomers and 1- and 2-NS isomers was not complete. The elution sequence and the separation efficiency among the NS isomers are discussed with reference to the molecular structures of the macrocyclic polyamines and the NS isomers.

The interaction of 2-naphthalenesulfonate (2-NS) with β-cyclodextrin (β-CD) was investigated in a 0.1 M phosphate buffer at pH 7.4 using an LKB 2277 microcalorimeter and a flow-mixed mode at 25°C. The thermodynamic parameters for inclusion complex formation obtained were as follows : ΔG°=-14.7 kJ/mol (K=381 M-1), ΔH°=-26.4 kJ/mol, ΔS°=-39.1 J/mol K. The formation constant K was determined as 428 M-1 at the same temperature from the change in chemical shift of the proton nuclear magnetic resonance spectra (1H-NMR) in 0.1 M phosphate buffered deuterium oxide solution at pD 7.4. The main driving force for inclusion complex formation was considered to be the van der Waals-London dispersion force. From measurements of the 1H-NMR and model building with Corey-Pauling-Koltun atomic models, the probable structure of the complex was determined to be : the naphthalene ring of 2-NS is included deeply at the head of 6-H and 7-H of 2-NS in the cavity of β-CD from the secondary hydroxy group side, the sulfonate group being outside the cavity.

Salicylate 1,2-dioxygenase, a new ring-fission dioxygenase from the naphthalenesulfonate-degrading strain Pseudaminobacter salicylatoxidans which oxidizes salicylate to 2-oxohepta-3,5-dienedioic acid by a novel ring-fission mechanism, has been crystallized. Diffraction-quality crystals of salicylate 1,2-dioxygenase were obtained using the sitting-drop vapour-diffusion method at 277 K from a solution containing 10%(w/v) ethanol, 6%(w/v) PEG 400, 0.1 M sodium acetate pH 4.6. Crystals belong to the primitive tetragonal space group P4(3)2(1)2 or P4(1)2(1)2, with unit-cell parameters a = 133.3, c = 191.51 A. A complete data set at 100 K extending to a maximum resolution of 2.9 A was collected at a wavelength of 0.8423 A. Molecular replacement using the coordinates of known extradiol dioxygenases structures as a model has so far failed to provide a solution for salicylate 1,2-dioxygenase. Attempts are currently being made to solve the structure of the enzyme by MAD experiments using the anomalous signal of the catalytic Fe(II) ions. The salicylate 1,2-dioxygenase structural model will assist in the elucidation of the catalytic mechanism of this ring-fission dioxygenase from P. salicylatoxidans, which differs markedly from the known gentisate 1,2-dioxygenases or 1-hydroxy-2-naphthoate dioxygenases because of its unique ability to oxidatively cleave salicylate, gentisate and 1-hydroxy-2-naphthoate with high catalytic efficiency.

Photochemical oxidation methods can be successfully used to eliminate hydrophilic xenobiotics in the water phase with a high efficiency. The influence of nitrate on the photochemical degradation kinetics of organic micropollutants in the presence of H2O2 proved to be different from its influence in the absence of H2O2. In the presence of H2O2, nitrate acts as an “inner filter” and reduces the UV light intensity in the photoreactor. As a consequence, the degradation rate of the micropollutants in the UV H 2 O 2 process decreased with increasing nitrate concentration. The degradation rate of the photolysis (UV irradiation only) was enhanced in the presence of nitrate. This could be explained by the formation of HO radicals during the nitrate photolysis. The influence of nitrate on the degradation rates in both UV processes was significantly more distinct for the irradiation of λir = 222 nm compared to the degradation at λir = 254 nm. This is mainly caused by a higher UV absorption of nitrate at the shorter wavelength. Problems with this technology can arise because nitrite and peroxynitrite were formed during UV irradiation of nitrate.

A novel water-soluble photochemical microreactor has been prepared. A perbutylated cyclodextrin bearing seven naphthalenesulfonate antenna chromophores (Bu-CD-N7) displays improved solubilization of hydrophobic guests in comparison with the unbutylated material (CD-N7). The photophysical properties of Bu-CD-N7 are similar to those of the CD-N7. The naphthyl chromophores of Bu-CD-N7 were used to sensitize the photolysis of 9-anthrylmethyl pivalate (AP). Inclusion of AP in the cyclodextrin leads to the selective formation of one of the two possible coupling products.

Picosecond time-resolved total internal reflection fluorescence spectroscopy was applied to study the microenvironments of 8-anilino-1-naphthalenesulfonate molecules at the heptane-water interface. By analyzing the fluorescence decay profiles, it was found that the fluorophores in the vicinity of the interface are present in two different solvated structures. One of them is located up to a few nanometers from the interface, and the other is located in a relatively wide range toward the aqueous phase. The former solvated structure is the cause of a long fluorescence lifetime which reflects the low polarity or the extremely high viscosity of the microenvironments.

A novel positively charged pillar[6]arene derivative bearing twelve pyridinium moieties has been synthesized. Its efficient complexation behavior towards two anionic naphthalenesulfonate substrates in aqueous media is described.

This study describes the optimum conditions at the staining time and the signal intensity for using 8-anilino-1-naphthalenesulfonate (ANS) as a fluorescent probe to detect proteins in SDS-PAGE. Using the optimized protocol, protein can be easily detected by short time fixing (20 min) and washing (2 × 5 min), followed by 10 min of staining. As low as 1-2 ng of the protein band can be detected, approximately thirty-fold higher than that of the original protocol. Furthermore, the compatibility of the staining method with MS was also explored by comparing the peptide mass fingerprinting results data of serial dilutions of BSA and ovalbumin stained by ANS with SYPRO Ruby.

The naphthalenesulfonate-oxidizing bacterium Sphingomonas sp. BN6 was immobilized in calcium alginate. These beads were incubated under aerobic conditions in a medium with the sulfonated azo dye, Mordant Yellow 3 (MY3), and glucose. The immobilized cells converted MY3, but only a marginal turnover of the dye was found under these conditions with freely suspended cells of Sphingomonas sp. BN6. Under anaerobic conditions, suspended cells of Sphingomonas sp. BN6 reductively cleaved the azo bond of MY3 to 6-aminonaphthalene-2-sulfonate (6A2NS) and 5-aminosalicylate. The turnover of MY3 by the immobilized cells under aerobic conditions resulted in the formation of more than equimolar amounts of 5-aminosalicylate, but almost no (6A2NS) was detected. Cells of Sphingomonas sp. BN6 aerobically oxidize 6A2NS to 5-aminosalicylate. It was therefore concluded that the cells in the anaerobic center of the alginate beads reduced MY3 to 6A2NS and 5-aminosalicylate and that 6A2NS was oxidized to 5-aminosalicylate by those cells that were immobilized in the outer aerobic zones of the alginate beads. The presence of oxygen gradients within the alginate beads was verified by using oxygen micro-electrodes. A coimmobilisate of Sphingomonas sp. BN6 with a 5-aminosalicylate degrading bacterium completely degraded MY3. The immobilized cells also converted the sulfonated azo dyes Amaranth and Acid Red␣1.

We study the interaction of 1-anilino-8-naphthalenesulfonate (ANS) with human (HSA) and bovine serum albumin (BSA) by phase and modulation fluorescence spectroscopy. We determined that both HSA and BSA show one or two distinguishable fluorescent sites, depending of the ANS/serum albumin ratio. At above a 1∶1 ANS/HSA molar ratio, the steady-state emission spectra for ANS can be resolved in two components: component 1, emitting with a lifetime (τ1) of 16 ns and a λ1max of 478 nm, with a quantum yield (фf1) of 0.67, and component 2, with a lifetime (τ2) of 2-4 ns and a λ2max of 483 nm, with an average quantum yield (фf2) of about 0.11. Considering these findings, the binding analysis is fitted with a model of two independent sites. Site 1 has an association constantK as1=0.87×10(6)M(-1) and a capacity of 1.04 mol of ANS/mol of HSA, and site 2 aK as2=0.079×10(6)M(-1) and a capacity of 2.34 mol of ANS/mol of HSA. Analysis of fluorescence lifetime distributions shows that the rigidity of the fluorophore environment at site 1 changes when site 2 is occupied. These findings suggest an interconnection between the two sites and that ligands can stabilize the protein's globular structure. To assess the identity of the ANS binding sites we used diazepam as a marker of the site located at the IIIA HSA subdomain and aspirin as a marker of sites located at the IIIA and IIA HSA subdomains. Both ligands displace ANS only from site 1, suggesting that it corresponds to the binding site located at the IIIA sub-domain of the protein. We determined that theK as values for diazepam and aspirin are 0.113× 10(6) and 0.021×10(6) M (-1) respectively.

Hydrophilic xenobiotics can be eliminated in the UV/H2O2-process. The oxidation in this process is enhanced by the photolytically generated HO radicals. Bicarbonate is able to scavenge HO radicals. So it was expected that the degradation rates of the investigated xenobiotics were affected by the influence of bicarbonate. In contrast to the widely described decrease of the degradation rate, a much more complex situation was found in this investigation. The degradation rates of 2-amino-1-naphthalenesulfonate and diphenyl-4-sulfonate were decreased and reached for high concentrations of bicarbonate the values of the photolytical degradation rate. The degradation of 4,4′-diaminostilbene-2,2′-disulfonate was accelerated significantly in the presence of bicarbonate. The degradation rate of EDTA was increased at small concentrations of bicarbonate and decreased at higher concentrations. Photochemischer Abbau hydrophiler Syntheseprodukte im UV/H2O2-Prozes. Einflus von Hydrogencarbonat auf die Abbaugeschwindigkeit von EDTA, 2-Amino-1-naphthalinsulfonat, Diphenyl-4-sulfonat und 4,4′-Diaminostilben-2,2′-disulfonat Hydrophile Syntheseprodukte konnen im UV/H2O2-Prozes mit einer hohen Effizienz abgebaut werden. Die Oxidationsgeschwindigkeit wird entscheidend von den photolytisch gebildeten HO-Radikalen bestimmt. Da das Hydrogencarbonat mit den HO-Radikalen reagieren kann, beeinflust es die Abbaugeschwindigkeit der untersuchten Substanzen. In dieser Arbeit zeigte sich, das die Rolle des Hydrogencarbonats wesentlich vielfaltiger ist, als bisher angenommen. Es konnte im Gegensatz zu den in der Literatur beschriebenen Effekten keine allgemeine Verlangsamung des Abbaus beobachtet werden. Der Abbau des 2-Amino-1-naphthalinsulfonats und des Diphenyl-4-sulfonats fand in Gegenwart von Hydrogencarbonat deutlich langsamer statt als in seiner Abwesenheit. Fur 4,4′-Diaminostilben-2,2′-disulfonat wurde in Gegenwart von Hydrogencarbonat jedoch eine deutlich erhohte Abbaugeschwindigkeit beobachtet. Der EDTA-Abbau war bei geringen Hydrogencarbonatkonzentrationen wesentlich schneller als in Abwesenheit von Hydrogencarbonat und wurde bei einer weiteren Erhohung der Hydrogencarbonatkonzentration wieder langsamer.

Photochemical oxidation methods are able to eliminate hydrophilic xenobiotics with a high efficiency. In waters with high DOC values caused by humic substances (HS) which are able to absorb UV light, problems can result. The degradation rates of the micropollutants using irradiation wavelengths in the range between λ = 200 nm to λ = 260 nm are significantly influenced by HS. This is mainly caused by the high absorption of the HS at shorter wavelength. In the presence of HS, the photolytic degradation of EDTA and FeEDTA was slowed down by an inner filter effect. A similar tendency could be seen for the photolytic degradation of 2-amino-1-naphthalenesulfonate where additional effects to the inner filter effect were also operating. In the UV/H 2 O 2 -process, the decrease of the degradation rate could be assigned to the ability of the HS to scavenge HO radicals.

The molecular mass distribution of naphthalenesulfonate condensation products (PNS) was investigated using ion-pair reversed-phase chromatography and ultrafiltration. The chromatograms obtained under an optimized solvent elution program yielded nearly 20 well resolved peaks corresponding to low and intermediate molecular mass species. A distinct broad peak was also resolved and attributed to polymeric species with relative molecular mass in excess of 5000. Under isocratic elution conditions, a linear relationship was obtained between the peak number and the log of the retention time for the first 17 peaks, thus indicating a homologous series of linear oligomers. The fractionation of the PNS mixtures by ultrafiltration enabled further resolution of the high molecular mass species; the latter also exhibited a broad distribution of molecular mass. Significant differences were also found amongst different commercial PNS products with similar average chemical composition.

The interaction of 8-anilino-1-naphtalenesulfonate (ANS) with heptakis(2, 3, 6-tri-O-methyl)-β-cyclodextrin (TOM-β-CD) was investigated in a 0.1 M phosphate buffer at pH 7.4 by fluorescence spectrophotometry. Utilizing the fact that the fluorescence intensity of ANS increases in the presence of TOM-β-CD, the thermodynamic parameters for inclusion complex formation were determined as follows : ΔG°=-8.95kJ·mol-1 at 25°C, ΔH°=-10.9kJ·mol-1, ΔS°=-6.3J·mol-1·K-1. The main driving force for the inclusion complex was considered to be the van der Waals-London dispersion forces, while the contributions of the hydrophobic interaction was small. Also, from the measurements of proton nuclear magnetic resonance spectra and studies with Corey Pauling Koltun models, the probable structure of the complex was determined. Further, the effects of permethylation on inclusion complex formation were discussed.

Calcium binding to β-lactoglobulin in the native and preheated forms was studied using an ion-selective electrode, and the structural changes induced were studied by fluorescence spectroscopy. Ca binding to β-lactoglobulin showed a small increase with heat treatment and a larger increase with pH. The intrinsic fluorescence of β-lactoglobulin and aniline naphthalenesulfonate fluorescence showed significant increases with heat treatment and with the addition of CaCl 2 (1-15 mM). The reactive sulfhydryl group content also increased with the addition of CaCl 2 to native and preheated β-lactoglobulin

The interaction of 8-anilino-1-naphthalenesulfonate (ANS) with 2,6-di- O -methyl-cyclomaltoheptaose (2,6-DM-βCD) was investigated in a 0.1 M phosphate buffer at pH 7.4 by fluorescence spectrophotometry. Utilizing the fact that the fluorescence intensity of ANS increases in the presence of 2,6-DM-βCD, the thermodynamic parameters for inclusion complex formation were determined as follows: Δ D ° = −10.3 kJ·mol −1 at 25°C, Δ H ° = −13.4 kJ·mol −1 , Δ S ° = −10.9 J·deg −1 ·mol −1 . The main driving force for the inclusion complex formation was considered to be the Van der Waals-London dispersion forces, while the contribution of the hydrophobic interaction was small. Also, from the measurements of proton nuclear magnetic resonance spectra and studies with Corey-Pauling-Koltun models, the probable structure was determined.

Butyl-substituted naphthalenesulfonate formaldehyde condensates (C4NSF) with different molecular weights were synthesized. The structures were confirmed by NMR in terms of the appearance of the signal at δ = 3.3–4.0 ppm, and the molecular weights of the synthesized C4NSFs were compared by gel permeation chromatography (GPC). C4NSFs used as dispersants were compared to unmodified naphthalenesulfonate formaldehyde condensates (NSF) in their ability to disperse nonpolar particles (carbon black) and polar particles (TiO2) in water. Their dispersing ability was evaluated by both a viscosity method and a microscopy method. For dispersing carbon black in water, it was found that using C4NSFs as dispersing agents results in a lower viscosity, a lower yield value by the viscosity method, and a more homogeneous dispersion of particles as determined by microscopy. These results indicate that the butyl group enhances the dispersing ability of C4NSF. The effect of the butyl group on the dispersing ability of C4NSF was interpreted by the results of the measured adsorption amount that was also enhanced by the existence of the butyl group. For dispersing TiO2 in water, C4NSF results in a higher viscosity and a higher adsorption amount of the dispersed system than NSF. These phenomena were interpreted in terms of the hydrophobic interaction between the butyl groups and the bridging effect. © 1993 John Wiley & Sons, Inc.

trans-2-Fluorocyclohexyl 4-phenyl- benzoate, (1), Cl9H19FO2, M r = 298.36, monoclinic, P21/n, a = 6.9710 (1), b = 9.3896 (11), c = 23.826 (4) A,/3 = 93.518 (12) °, V= 1556.6/~3, Z = 4, Dx = 1.273 Mg m -a, A(Mo Ka) = 0.71069/~, /z = 0.08 mm-1, F(000) = 632, T = 293 K. Final R = 0.062 for 2396 unique observed reflections, trans-2- Fluorocyclohexyl diphenyl phosphate, (2), C18H2oFOaP, Mr=350.32, monoclinic, Cc, a= 16.644 (5), b = 9.27'.(3), c = 12.048 (4) A, /3 = 109.80 (3) °, V = 1750 A 3, Z = 4, Dx = 1.329 Mg m- A(Mo Ka) = 0.71069 A, /~ = 0.18 mm -1, F(000) = 736, T= 293 K. Final R = 0.029 for 2977 unique observed reflections, trans-2-Fluorocyclohexyl 2- naphthalenesulfonate, (3), C16HITFO35, Mr = 308.37, monocliuic, P21/c, a = 11.7709 (15), b= 15.601 (2), c = 8.2119 (12) A,/3=94.728(15) °, V= 1502.9 A 3, Z = 4, Dx = 1.363 Mg m -3, a(Mo Ka) = 0.71069 A,/z = 0.22 mm-1, F(000) = 648, T = 293 K. Final R = 0.053 for 2098 unique observed reflections. The three related structures have both substituents equatorial, and C--F thus gauche to the C---OX bond. The introduction of the 2-fluorine atom is associated with a significant shortening of the C---O bond only in the sulfonate ester.

1-Anilino-8-naphthalenesulfonate (ANS) was observed to undergo a number of photochemical processes, including ionization, dimerization and loss of sulfonate. A mechanism that involves monophotonic ionization is proposed for the photo-induced dimerization of ANS. Photoionization of ANS was demonstrated by the reduction of silver ions in solution, which in turn was verified by surface-enhanced Raman spectroscopy.

Naphthalenesulfonate mobile phases for chromatography with indirect photometric detection have been characterized for the separation and detection of common inorganic and organic anions using an ion-exchange column. The singly charged 2-naphthalenesulfonate (NMS) has shown good chromatographic performance for small singly charged inorganic anions such as F - , CI - , NO 2 - , Br - and NO 3 - with detection limits ranging from 20 to 4 ng. The doubly charged 1,5-naphthalenedisulfonate (NDS) was more efficient toward the separation and identification of small singly charged, multicharged, and large anions such as F - , CI - , NO 2 - , Br - , NO 3 - , SO 4 2- , S 2 O 3 2- , I - and SCN - . Analysis of a mixture containing the above anions can be performed in less than 16 min, with detection limits in the 20-1 ng range. The linear response range of these mobile phases were from 100 ppm to the detection limits of all anions (0.05-1 ppm). Both NMS and NDS require no pH adjustment for indirect photometric detection use, and no system peak was observed in any chromatogram.

Molar conductances of dilute solutions of sodium 2-naphthalenesulfonate at 25°C and of sodium 2-anthraquinonesulfonate have been measured at 25 and 37°C. These data are interpreted to show that the anthraquinonesulfonate anion is dimerized in solution. Dimerization constants and the enthalpy and entropy of dimerization are calculated. Spectrophotometric absorbancies have been measured at 25, 30, 35 and 40°C for a series of aqueous solutions containing both sodium 4-dimethylaminobenzenesulfonate and sodium 3-nitrobenzenesulfonate. Equilibrium constants and enthalpy and entropy changes for formation of the 1 ∶ 1 complex between these two ions have been calculated from these data. The formation of these complexes between like-charged ions, and of dimers of other aromatic solutes in water is discussed in terms of a two-state model of hydrophobic hydration.

Two beta-cyclodextrin (beta-CD) derivatives bearing steroid groups (1 and 2) were synthesized by the condensation of mono(6-aminoethylamino-6-deoxy)-beta-CD with cholic acid and deoxycholic acid, respectively, and their original conformations and binding behavior to the organic anion of naphthalenesulfonate derivatives were investigated by using 1H NMR spectroscopy and spectrofluorometric titration in combination with computational methods. The 2D NMR experiments reveal that the steroid groups attached to the beta-CD rim could be deeply embedded in the beta-CD cavity to form the intramolecular (for 1) or intermolecular (for 2) inclusion complexes in aqueous solution. Upon complexation with naphthalenesulfonate derivatives, modified beta-CDs display two obviously different binding modes, that is, the competitive inclusion mode and the induced-fit inclusion mode, which is consistent with the results of molecular modeling study. The two modes and the strict size/shape fitting relationship between the hosts and guests reasonably explain the different binding behaviors and molecular selectivity of host beta-CDs 1 and 2 toward the naphthalenesulfonate guests. Therefore, the cholic acid- or deoxycholic acid-modified beta-CDs could effectively recognize the size/shape of guest molecules as compared with the parent beta-CD, giving good molecular selectivity up to 24.9 for the disodium 2,6-naphthalenedisulfonate/disodium 1,5-naphthalenedisulfonate pair by the host 1.

Application of capillary electrophoresis (CE) to simultaneously determine the apparent binding constants and thermodynamic parameters for six positional and structural naphthalenesulfonate derivatives with β-cyclodextrin (β-CD) is presented. The change in electrophoresis mobilities was used to assess the binding constants by non-linear regression and three different linear plots methods (named double reciprocal, x -reciprocal and y -reciprocal). The substituent group(s) attached to the naphthalene ring considerably affected the inclusion behaviors of these naphthalenesulfonate derivatives. The binding constant varies over almost one order of magnitude and a highly selective sequence is obtained between these guest model compounds. Naphthalenesulfonates with the substituent(s) at the 2-position(s) displayed stronger interaction with β-CD, and gave well compatible results by these four plot methods. While at least one substituent was substituted into the 1-position of naphthalene showed the weak interaction or no interaction with β-CD. Comparison to three linear regression methods, the non-linear regression method proves to be the most suitable for these determinations. Additionally, apparent binding constants for each structural isomer with β-CD at several temperature, and thermodynamic parameters for binding were also calculated and discussed.

The effects of the type of buffer system, buffer pH, the polarity of electrode, and both the type and the concentration of cyclodextrins (CDs) on the separation and migration behavior of seven positional and structural naphthalenesulfonate isomers in CD-mediated capillary electrophoresis were systematically investigated. The most effective separation conditions were to use 20 mM phosphate buffer with β-CD at pH 3.0, while the polarity of the electrodes were reversed across the capillary. Under such conditions, these isomers can be separated in 10 min. The results also indicate that the interactions of naphthalenesulfonate derivatives with CDs are strongly affected by the position of the substituent(s) on the aromatic ring. The inclusion complex formation constants of these compounds were evaluated to improve our understanding of the interaction between the naphthalenesulfonate derivatives and CDs. Moreover, the formation constants of naphthalene-2-sulfonate to β-CD agreed closely with the data in the literature obtained by a spectrophotometric method and by CE methods in various pH buffers.

Quenched phosphorescence detection of camphorquinone in cyclodextrin-based electrokinetic chromatography provides very favorable detection limits, i.e., 7 x 10(-)(7) M, 3 orders of magnitude lower than conventional UV absorption detection at 200 nm. The detection is based on the dynamic quenching by the analyte of the strong phosphorescence emission of brominated naphthalenesulfonate, under deoxygenated buffer solution conditions. This approach has been used to detect (1S)-(+)- and (1R)-(-)-camphorquinone after enantiomeric separation by CE. Although the use of the negatively charged carboxymethyl beta-cyclodextrin (CM-beta-CD) alone was not successful, the addition of a second, neutral cyclodextrin, alpha-CD, provided an adequate enantiomeric separation of camphorquinone. Using 25 mM borate buffer (pH 8.5) with 10 mM CM-beta-CD and 20 mM alpha-CD (applied voltage 20 kV, ambient temperature), the enantiomeric separation was performed in approximately 14 min. The chiral method was applied to monitor the stereoselectivity of the biotransformation of a racemic mixture of camphorquinone by yeast. It was found that the enantiomeric ratio calculated from the peak areas in the electropherogram (RSD = 5%) after 24 h of incubation decreased from 0.92 for the control solution (culture medium without yeast) to 0.24 for the culture medium; a similar ratio of 0.25 was observed for cell extract solutions. Therefore, racemic camphorquinone is enantioselectively degraded by yeast, the biodegradation of (1S)-(+)-camphorquinone being faster than that of the (1R)-(-)-enantiomer.

A very sensitive analytical procedure based on LC–MS for determining trace amounts of the more relevant poly(naphthalenesulfonate) (PNS) contaminants present in environmental waters is presented. Extraction was performed on a styrene–divinylbenzene copolymer resin solid-phase extraction cartridge after addition of ammonium acetate to the sample. Small amounts of ammonium acetate in the mobile phase allowed the determination and characterisation of the four shorter oligomers by liquid chromatography–electrospray mass spectrometry. Under such conditions the electrospray process generates fully ionised molecules which greatly simplifies interpretation of spectra and quantitation. Additionally, confirmatory ions can be generated by the in-source collision-induced decomposition process. The effectiveness of the method was assessed in recovery experiments from drinking and river water samples spiked with commercial mixtures of PNS concrete plasticizers also referred as naphthalenesulfonate–formaldehyde condensates. Moreover, the performance of this method was compared to methods using ion-pair chromatography coupled with fluorimetric and mass spectrometric detection. Method detection limits were in the low picomolar range (1 ng/l for the monomer) for each isomer. In order to evaluate the environmental relevance of PNS type compounds waste, river and ground water grab samples were analysed. Concentrations of PNS oligomers detected in these samples ranged between 53 ng/l and 32 μg/l.

The inclusion mode of 8-anilino-1-naphthalenesulfonate (ANS) in the ANS-β-cyclodextrin complex with a molar ratio of 1 : 1 in deuterium oxide was investigated by measurements of the proton nuclear magnetic resonance spectra and studies with Corey Pauling Koltun models. It was found that in the preferential inclusion mode of ANS, the whole benzene ring of ANS is enclosed at a considerable depth in the cavity of β-cyclodextrin from the side of the secondary hydroxyl group, and a great portion of the naphthalene ring is outside the cavity.

“Neutral” water-soluble calix[n]arenes, 1n (n=6 and 8) were synthesized for the first time. Below the critical micelle concentrations, they formed host–guest-type complexes with naphthalenesulfonate derivatives used as fluorescence probes. The binding sites showed the hydrophobicity comparable with those of cyclodextrins, and the cavities showed the shape selectivity for these guest molecules.

In this work we have studied the interaction of the hydrophobic fluorescent probe 1,1'-bis(4-anilino-5-naphthalenesulfonate) (bis-ANS), with the native state of apo- and Ca2+-bound goat alpha-lactalbumin (GLA). In 10 mM Tris-HCl, pH 7.5, at 4 degrees C in 2 mM EGTA as well as at 37 degrees C in 2 mM Ca2+, the native protein is close to its thermal transition. Therefore, it can be expected that in both conditions the protein is equally susceptible to interaction with bis-ANS. Nevertheless, we have observed a number of interesting differences in the interaction of the dye with the apo and Ca2+ form. Native apo-GLA binds two bis-ANS molecules and in the complex with bis-ANS, the far-UV circular dichroism (CD) spectrum of apo-GLA becomes similar to that of the protein in the molten globule state. In contrast, native Ca2+-GLA binds five bis-ANS molecules and the far-UV CD spectrum of native Ca2+-GLA is conserved for the complex. In both cases, the high activation energies observed in kinetic experiments indicate that upon binding, large parts of the protein structure have to be reorganized. The reduced perturbation of the protein structure in the presence of Ca2+ can be attributed to local stabilization effects.

The hypothesis that 2-toluidino-6-naphthalenesulfonate (TNS), a negatively charged probe for hydrophobic regions of proteins, may antagonize volatile anesthetics was tested in goldfish. TNS at 100 μM increased EC50 2-fold for halothane and 1.5-fold for isoflurane. High hydrophobicity and negative charge of TNS may play a key role for antagonization of volatile anesthetics.

Sonicated lipid micelles, formed from phospholipids isolated from yolks of fresh hen eggs, were used as a model membrane system for studying the effects of several surfactants on membrane properties. The interactions of the surfactants with the model system were followed through the fluorescence of the hydrophobic probe l-anilino-8-naphthalenesulfonate. The surfactants investigated were polyoxyethylene sorbitan monolaurate (Tween 20), polyoxyethylene thioether (Sterox SK), mono-calcium salt of polymerized aryl alkyl sulfonic acids (Daxad 21), and alkylbenzyl quaternary ammonium halide (AHCO DD 50). All surfactants enhanced fluorescence of the membrane-bound probe, and the degree of this enhancement correlated with the previously established phytotoxicity of these substances. The results indicate that surfactants can produce distinct changes in artificial phospholipid membranes and suggest that this lipid interaction may account for altered membrane permeability characteristics in surfactant-treated plants. The effects are observable for surfactant concentrations as low as 0.0001% (w/v), representing an approximate 10-fold increase in sensitivity for detecting surfactant effects compared with previous results on permeability changes in isolated plant cells.

It was indicated from fluorescence spectra and fluorescence titration that a hydrophobic probe, 1-anilino-8-naphthalenesulfonate (ANS), binds to casein components (αs-, β- and κ-caseins). Fluorescence intensity and affinity of ANS-κ-casein complex were larger than that of ANS-αs- and ANS-β-casein complexes. Enhancements of fluorescence intensity of complexes of casein components were observed by the addition of KCI or CaCl2. Reason for the enhancement was postulated to be the increase of the quantum yield of the ANS fluorescence caused by the environmental change of ANS binding region of the casein components.Marked increase of sedimentation coefficient of β-casein in the presence of KCl or CaCl2 at 10°C was caused by the addition of ANS. This may be responsible for the stimulation of the Ca-dependent precipitation of β-casein by the addition of ANS.It was found that αs · κ-association was prevented by ANS and that hydrophobic interaction have an important role for αs · κ-association.

Spectrofluorometric studies using 1-anilino-8-naphthalenesulfonate (ANS) reveal that Z-fraction from rat liver has far the more hydrophobic binding sites than the other cytoplasmic binding fractions X and Y. Diagnostically important organic anions, such as sulfobromophthalein (BSP) and rose bengal (RB), are shown to displace ANS from Z-fraction by quenching the fluorescence of ANS and Z-fraction mixture without the change of quantum yield and emission maximum. The binding constants of these dyes to Z-fraction are determined by the competitive studies with ANS, and are coincident with those from other methods. Since the spectrophotometric technique reveals that the number of RB binding sites on Z-fraction is about twice as large as that of ANS binding sites, ANS and RB do not have necessarily the identical binding sites, though they must have partly common ones. The major binding force between organic anions and Z-fraction is supposed to be hydrophobic considering that the binding constant of Z-fraction for ANS is only about one-eight of that of bovine serum albumin (BSA) of which site is both hydrophobic and cationic. This property of sites accounts for the lower affinity for BSP of Z-fraction extracted from CCl4 chronically intoxicated rats, which our former study has made clear.