Saccharides In Aqueous Solutions Research Articles

Boronic acid‐based thin films that show saccharide‐responsive multicolor changes

ABSTRACTA novel saccharide sensor that displays a distinct color change resembling a “traffic signal” was developed. By copolymerizing boronic acid and amine monomers on a glass plate, a boronic acid‐containing thin film was obtained. Anionic blue and yellow dyes were adsorbed on the thin film, and the film was immersed in aqueous saccharide solutions containing a cationic red dye. With increase in the saccharide concentration in the solution, the thin film changes color from green to red via yellow. The observed distinct changes in color were attributed to a stepwise release and binding of dyes. The sensitivity of the saccharide sensor was dependent on the monomer composition of the thin film and increased with increasing the boronic acid content. The pH of the saccharide solution was another key factor affecting the sensing behavior, and glucose‐responsive color changes were significantly enhanced at pH 7.8. By optimizing these conditions, significant color changes in response to glucose were achieved. Saccharide selectivity was found to be in the following order: fructose > glucose > galactose = mannose > sucrose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42679.

Solution structures of methyl aldopyranosides revealed by vacuum-ultraviolet electronic circular-dichroism spectroscopy

Vacuum-ultraviolet (VUV) electronic circular-dichroism (ECD) spectra of methyl β-D-glucopyranoside (methyl β-D-Glc), methyl α- and β-D-galactopyranosides (methyl α- and β-D-Gal), and methyl α- and β-D-xylopyranosides (methyl α- and β-D-Xyl) were measured down to 163 nm in aqueous solution using a s ynchrotron-radiation VUV-ECD spectrophotometer. Five methyl aldopyranosides exhibited characteristic ECD spectra depending on the gauche (G) and trans (T) conformations of the hydroxymethyl group at C-5 and the α-/β-anomer configurations of the methoxy group at C-1. To elucidate the contributions of these structures to the spectrum, the ECD spectra of three rotamers (GT, GG and TG) of methyl β-D-Glc, methyl α-D-Gal and methyl β-D-Gal were calculated using a time-dependent density functional theory and molecular dynamics simulations. These theoretical spectra were very similar to those observed experimentally, indicating that the GT and GG rotamers show negative and positive ECD around 170 nm, respectively, and that the α- and β-anomers exhibit negative and positive ECD around 160 nm, respectively. These spectral differences between the two rotamers and between the two anomers were attributable to changes in steric configurations, including the intramolecular hydrogen bond around the ring oxygen and the methoxy oxygen, respectively. These relationships were supported by the ECD spectra experimentally observed for methyl α-D-Xyl and methyl β-D-Xyl, demonstrating that the VUV-ECD spectroscopy is a powerful technique for characterizing the structures of saccharides in aqueous solution.

Formation of ether-functionalized ionic-liquid-based aqueous two-phase systems and their application in separation of protein and saccharides.

Ionic-liquid (IL)-based aqueous two-phase systems (ATPSs) have attracted much attention in the separation technology. In this work, we synthesized five novel ether-functionalized ILs and studied their applications in ATPS formation. The phase diagrams for several systems were determined at 298.15 K. An as-prepared IL (1-(2-butoxy-ethyl)-3-methylimidazolium chloride) was chosen as a representative to construct ATPSs for separation of bovine serum albumin (BSA) from aqueous saccharide solutions. Results showed that 76.1-94.3% of BSA was enriched into the IL-rich top phase and almost all the saccharides were extracted into the salt-rich bottom phase in a one-step separation process. The main factors affecting the separation process, such as kinds of saccharides and the amount of inorganic salts, were discussed. Furthermore, the size distributions of aggregates in the IL-rich top phase were determined by dynamic light scattering (DLS), and accordingly the possible mechanism for the separation was investigated.

Conductivities for ZnSO4/MgSO4 + sucrose/trehalose + water systems at 298.15 K

Conductivities for ZnSO4/MgSO4+sucrose/trehalose+water solutions were measured at 298.15K. The limiting molar conductivities (Λ0) and association constants (KA) were derived using the Lee–Wheaton conductivity equation. From the obtained conductivity data, the values of the Walden product (Λ0η0) were also calculated. These parameters have been interpreted in terms of ion–ion and ion–solvent interactions in aqueous saccharide solutions.

Partial Molar Volumes and Isentropic Compressibilities of Some Saccharides in Aqueous Solutions of Leucine at Different Temperatures

In the present study, densities, ρ, and velocities of sound, u, have been measured for mono-, di-, and trisaccharides at molalities ranging from (0.0 50 to 0.100) mol·kg–1 in aqueous solutions of leucine (0.025, 0.050, and 0.100) mol·kg–1 over a wide temperature range (293.15 to 313.15) K. By using density and velocities of sound data the partial molar volumes, ϕvo, isentropic compressibilities, κs, and partial molar isentropic compression, ϕko, for different saccharides have been evaluated. The trends of variation of different parameters have been interpreted in light of the solute–solvent/cosolute and solute–solute interactions occurring in these systems. An attempt has also been made to compare the results with the corresponding results in aqueous electrolyte solutions.

Multicolor saccharide-sensing chips created via layer-by-layer adsorption of boronic acid-containing polymers

A novel saccharide-sensing chip that shows a distinct color change was developed. The saccharide-responsive thin films were obtained on a pattern-printed microscope slide via a layer-by-layer method utilizing a boronic acid-containing polycation. After adsorption of anionic dyes, the thin films were immersed in aqueous saccharide solutions. As the saccharide concentration increased, the thin films showed a multi-patterned color change that enabled the quantification of saccharides using multi-colorimetric sensing.

Multicolor Saccharide-analysis Sensor Arrays Based on Boronic Acid-containing Thin Films Combined with Various Anionic Dyes

Abstract A novel saccharide sensor array that shows distinct color changes was developed. By copolymerizing a boronic acid monomer and an amine monomer on a pattern-printed microscope slide, boronic acid-containing thin films were obtained. After adsorbing anionic dyes on the thin films, the sensor array thus obtained was immersed in aqueous saccharide solutions. As the saccharide concentration increased, the sensor array distinctly changed its color. This methodology enables us to measure saccharide concentration with ease by pattern-based sensing utilizing multiple color changes of the sensor array.

Conductivity in MnSO4–saccharide–water solutions at 298.15 K

Conductivities for MnSO4–saccharide (d-glucose, d-galactose and d-fructose)–water solutions were measured, together with densities, viscosities of the aqueous saccharide solutions at 298.15K. According to the Lee–Wheaton conductivity equation, limiting molar conductivities Λ0 and association constants KA were obtained. The Walden products (Λ0η0) were also calculated. These parameters have been interpreted in terms of ion–ion and ion–solvent interactions in aqueous saccharide solutions.

Vacuum-Ultraviolet Electronic Circular Dichroism Study of Methyl α-d-Glucopyranoside in Aqueous Solution by Time-Dependent Density Functional Theory

The vacuum-ultraviolet (VUV) electronic circular dichroism (ECD) spectrum of methyl α-D-glucopyranoside (methyl α-D-Glc) was measured down to 163 nm in aqueous solution using a synchrotron-radiation VUV-ECD spectrophotometer. The spectrum exhibited two characteristic ECD peaks around 170 nm, which depend on the trans (T) and gauche (G) configurations of the hydroxymethyl group at C-5. To elucidate the influences of the T and G configurations on the spectrum, the ECD spectra of three rotamers (α-GT, α-GG, and α-TG) of methyl α-D-Glc were calculated using time-dependent density functional theory (TDDFT) combined with molecular dynamics simulation. A linear combination of the ECD spectra of these three rotamers, which differ markedly from each other, produced a methyl α-D-Glc spectrum similar to that observed experimentally. The spectrum was assignable to the n-σ* transitions of the ring oxygen and methoxy oxygen with minor contributions from the hydroxyl oxygen. The differences in α-GT, α-GG, and α-TG spectra were attributed to fluctuations of the configurations of the hydroxymethyl group at C-5 and the hydroxyl group at C-4, which strongly affected the orientations of intramolecular hydrogen bonds around the ring oxygen. These findings demonstrate that combining VUV-ECD and TDDFT is useful for structural characterization of saccharides in aqueous solution.

Calorimetric and Theoretical Study of the Interaction between Some Saccharides and Sodium Halide in Water

Dilution enthalpies and mixing enthalpies of sodium halide and some saccharides (glucose, galactose, xylose, arabinose, fructose, and sucrose) in aqueous solution were determined by calorimetric measurements at 298.15 K. The values were used to determine enthalpic pair interaction parameters. Combined with Gibbs energy pair parameters, entropic pair interaction parameters were also obtained. Theoretical calculations at the B3LYP/6-311++G(d,p) level were carried out to provide the information of structures and thermodynamic functions. The information reveals the thermodynamic essence of the interactions between sodium halide and saccharides in aqueous solutions. The experimental results and theoretical calculations show that the sign of enthalpic pair interaction parameter 2υh(ES) is determined by the direct interaction between saccharides and ions, whereas the difference in value of 2υh(ES) for different saccharides or electrolytes depends on the partial dehydration of saccharides or anions in aqueous solution. The difference in value of entropic pair interaction parameters depends partly on the different dominant interactions in the process of partial dehydration of saccharides or ions. An enthalpy-entropy compensation relationship was observed for the sodium bromide-aldopyranose-water systems. Remarkably, it can be conjectured that the hydration entropy of glucose is lower than for other monosaccharides. Perhaps it is one of the reasons why glucose plays an important role in living organisms rather than other monosaccharides.

Non-covalently lactose imprinted polymers and recognition of saccharides in aqueous solutions

The aim of this work was to prepare lactose imprinted polymer and study of its selectivity for the recognition of different mono- and disaccharides. A series of molecularly imprinted polymers (MIPs) against lactose were synthesized and their binding properties were compared with a Blank non-imprinted polymer. Methacrylamide (MAAM) and ethylene glycol dimethacrylate were used as functional monomer and cross-linker, respectively. Dimethylsulfoxide was also applied as polymerization solvent. Different lactose:MAAM ratios were applied and optimized MIP was selected in a conventional batch adsorption study. The dissociation constant and maximum binding sites of polymer were determined using the Scatchard analysis. The selectivity of MIP for different mono- and disaccharides was also evaluated. The results indicated that the shape of cavity and orientation of functional monomers in binding sites and the spatial arrangement of hydroxyl groups in saccharide structure were responsible for the selectivity of lactose imprinted polymer.

A Multicolor Saccharide Sensing Chip Created by Layer-by-Layer Adsorption of a Boronic Acid-containing Polymer

A novel saccharide sensor array that shows distinct color change was developed. By the layer-by-layer method utilizing boronic acid-containing polycation and polyanion, saccharide-responsive thin films were obtained on a pattern-printed microscope slide. After adsorbing anionic dyes, the thin films were immersed in aqueous saccharide solutions. As saccharide concentration increased, the thin films clearly changed their color. Since the color changed occurred at different saccharide concentrations depending on anionic dyes, the sensor array showed a multipactor color change which enables us to quantify saccharides by a pattern-based sensing.

Multicolor saccharide-sensing chips based on boronic acid-containing thin films showing stepwise release and binding of dyes

A novel saccharide sensor that shows a distinct color change resembling a “traffic signal” was developed. By copolymerizing a boronic acid monomer and an amine monomer on a glass plate, a boronic acid-containing thin film was obtained. After adsorbing anionic blue and yellow dyes, the thin film was immersed in aqueous saccharide solutions containing a cationic red dye. As saccharide concentration increased, the thin film changed its color from green to red via yellow. Origin of the distinct color change was attributed to a stepwise release and binding of dyes.

Galactosyl oligosaccharide purification by ethanol precipitation

Galactosyl oligosaccharides (GOS) are prebiotics commonly manufactured by β-galactosidase conversion of lactose, producing a mixture containing GOS, lactose, glucose and galactose. Enrichment of GOS in this mixture adds value to the product. This study aimed to determine whether the addition of ethanol to aqueous saccharide solutions could be used to selectively precipitate and enrich GOS from a reaction mixture. High concentrations of ethanol (>70% v/v) were required to induce precipitation. The total saccharide concentration was a significant variable, with higher GOS enrichment occurring at lower total saccharide concentrations. Varying the temperature between 10 and 40 °C had less impact than had changes in the concentration of saccharide or ethanol. GOS was enriched 2.3 (±0.1) fold in the precipitate formed in a solution of 90% (v/v) ethanol with 28 g/L of total saccharide at 40 °C. Performing two such precipitations sequentially reduced the monosaccharides from 48% (w/w) of the total saccharides to 4% (w/w). GOS precipitation has potential for industrial application as it is simple in operation and offers levels of purification similar to those by other techniques.

Interactions of Diglycine in Aqueous Saccharide Solutions at Varying Temperatures: A Volumetric, Ultrasonic and Viscometric Study

Densities, viscosities and speeds of sound were measured for ternary mixtures of diglycine (0.05 to 0.30 mol⋅kg−1) in 2, 4 and 6 mass-% aqueous xylose, L(-)arabinose, and D(-)ribose solutions at 288.15, 298.15 and 308.15 K and at atmospheric pressures, using a DSA 5000 instrument. The limiting apparent molar volume, limiting apparent molar adiabatic compressibility and their corresponding slopes were computed using the density and speed of sound data. Corresponding transfer functions have also been determined. The viscosity data have been analyzed on the basis of the Jones-Dole equation. The viscosity B-coefficient and Gibbs energy of activation of viscous flow per mole of solvent and solute have been evaluated. Hydration numbers, pairwise and triplet interaction coefficients have also been evaluated from these data. The variations of these parameters with concentration and temperature clearly suggest the roles of diglycine and saccharides in solute–solvent interactions.

Selective separation of protein and saccharides by ionic liquids aqueous two-phase systems

In the present work, it was found that aqueous solution of a hydrophilic ionic liquid (IL), 1-butyl-3-methylimidazolium dicyanamide ([C4mim][N(CN)2]), could be separated into an aqueous two-phase system (ATPS) by inorganic salts such as K2HPO4 and K3PO4. The top phase is IL-rich, while the bottom phase is phosphate-rich. It was shown that 82.7%–100% bovine serum albumin (BSA) could be enriched into the top phase and almost quantitative saccharides (arabinose, glucose, sucrose, raffinose or dextran) were preferentially extracted into the bottom phase in a single-step extraction by [C4mim][N(CN)2] + K2HPO4 ATPS. The extraction efficiency of BSA from the aqueous saccharide solutions was influenced by the molecular structure of saccharides. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were combined to investigate the microstructure of the IL-rich top phase and the possible mechanism for the selective separation. It is suggested that the formation of the IL aggregate and the IL aggregate-BSA complex plays a significant role in the separation of BSA from aqueous saccharide solutions. This is the first example for the selective separation by ILs-based ATPSs. It is expected that these findings would have potential applications in bio-analysis, separation, and IL recycle.

ChemInform Abstract: Selective Fluorescence Signalling of Saccharides in Their Furanose Form.

A boronic acid binding site and biphenyl fluorophore has been used to create a fluorescent PET (photoinduced electron transfer) sensor for saccharides in aqueous solution at pH 7.77. Formation of five or six membered cyclic boronate esters can be “read out” by the relative fluorescence intensity.

Dosimetric characteristics of different types of saccharides: An EPR and UV spectrometric study

The time stability and dose response of the free radicals produced in various types of “less-studied” mono- and disaccharides by γ-radiation is studied by EPR (Electron Paramagnetic Resonance) and UV spectrometry. The time evolution of the shape of the EPR spectra of irradiated saccharides is investigated from 5 min to 5 months after irradiation. The intensity of the stable EPR signal is studied as a function of the absorbed γ-dose in the range 0.5–20 kGy. Aqueous solutions of irradiated solid saccharides exhibit a UV absorption maximum in the range 250–290 nm. A linear dependency is found between the magnitude of the UV absorption maximum and the absorbed γ-dose. The time stability of the UV absorption maximum is also studied for every saccharide. The results are compared with those obtained for irradiated sucrose.

Volumetric, viscometric, and acoustic behaviour of diglycine in aqueous saccharide solutions at different temperatures

Density, ρ, speed of sound, u, and viscosity, η measurements have been carried out on diglycine (0.05–0.30 mol kg − 1 ) in aqueous glucose, galactose and fructose solutions ranging from pure water to 6 mass % of saccharides at 288.15, 298.15 and 308.15 K. These data were used to calculate the corresponding apparent molar volume, V ϕ , limiting apparent molar volume, V ϕ 0, transfer volume Δ tr V ϕ 0, viscosity B-coefficients of Jones–Dole equation, apparent molar adiabatic compressibility, K ϕ,S , limiting apparent molar adiabatic compressibility, K ϕ,S 0, and its transfer values Δ tr K ϕ,S 0 at infinite dilution. The activation free energy, Δ μ 2 0⁎, for viscous flow in different aqueous saccharide solutions have been calculated from B-coefficient and partial molar volume data. Hydration numbers, n H and interaction coefficients, Y AB , and Y ABB , have also been calculated from these data. These parameters have been discussed in terms of solute–solvent interactions. We have also attempted to examine the temperature and concentration dependence of such interactions.

Volumetric and ultrasonic studies of diglycine in binary aqueous solutions of saccharide at 288.15, 298.15 and 308.15 K

Densities, speeds of sound and viscosities of diglycine have been measured at 288.15, 298.15 and 308.15 K in aqueous saccharides solutions ranging from 1.0 to 5.0 mass% of saccharide. The saccharides used are mannose, maltose and raffinose. From density, viscosity and speed of sound data, apparent molar volumes V ϕ , relative viscosity η r and adiabatic compressibilities K φ,s of diglycine have been determined. The viscosity data have been analysed using the Jones-Dole equation. Partial molar volumes V φ 0 and partial molar adiabatic compressibilites K φ,s 0 of diglycine at infinite dilution were evaluated. These values are required for calculating hydration number n H of diglycine. Transfer volumes ΔV φ 0 , and transfer adiabatic compressibilites ΔK φ 0 from water to aqueous saccharide solutions have been calculated. The results have been discussed in terms of solute-solute and solute-solvent interactions and the structural changes of the solutes in solutions.