Dielectric Relaxation of Aqueous Solution with Low-molecular-weight Nonelectrolytes and Its Relationship with Solution Structure

Saito, Akio; Miyawaki, Osato; Nakamura, Kozo

doi:10.1271/bbb.61.1831

Cited by 28 publications

(16 citation statements)

References 7 publications

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“…(9) has a meaning as an index of the solvent ordering in aqueous solutions. The parameter α showed a good correlation with solvent‐ordering parameters reported in the literature such as the B coefficient of viscosity for electrolytes31 and nonelectrolytes,32 the number of equatorial —OH groups for carbohydrates,33 and dielectric relaxation time of water molecules in nonelectrolyte solutions 34. The parameter α, as an index of the solvent ordering, was useful to explain the effect of the coexistence of cosolutes on the thermal stability of proteins30 and enzyme kinetics 35.…”

Section: Resultsmentioning

confidence: 60%

Effect of water potential on sol–gel transition and intermolecular interaction of gelatin near the transition temperature

et al. 2003

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The sol-gel transition of gelatin, measured by thermal analysis and viscosity measurement, was analyzed in terms of the change in hydration state of polymer molecules. A new thermodynamic model was proposed in which the effect of water potential is explicitly taken into account for the evaluation of the free energy change in the sol-gel transition process. Because of the large number of water molecules involved and the small free energy change in the transition process, the contribution of water activity, a(W), was proved to be not negligible in the sol-gel transition process in solutions containing such low-molecular cosolutes as sugars, glycerol, urea, and formamide. The gel-stabilization effect of sugars and glycerol was linear with a(W), which seemed consistent with the contribution of water potential in the proposed model. The different stabilization effect among sugars and glycerol was explained by the difference in solvent ordering, which affects hydrophobic interaction among protein molecules. The gel-destabilization effect of urea and formamide could be explained only by the direct binding of them to protein molecules through hydrogen bonding. On the contrary, the polymer-polymer interaction, measured by the viscosity analysis, in polyethyleneglycol and dextran solutions was not sensitive to the change in a(W), suggesting that no substantial change in hydration state with a(W) occurred in these polymer solutions.

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Section: Resultsmentioning

confidence: 60%

Effect of water potential on sol–gel transition and intermolecular interaction of gelatin near the transition temperature

et al. 2003

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“…Miyawaki and co-workers [16,17] calculated the water activity in sugar solutions from the measurement of the freezing point depression and evaluated the parameter α. They have revealed that including the measurement of the dielectric relaxation time [25]. As shown in Table 1, the measurement of the vapor pressure tended to give a value of α smaller than that evaluated from the measurement of the freezing point depression for unknown reasons.…”

Section: Equilibrium Constant Of Hydration and Hydration Numbermentioning

confidence: 99%

Dielectric Relaxation and Water Activity in Aqueous Solution of D-Psicose

et al. 2011

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Hydration behavior of a rare sugar, D-psicose, was investigated based on measurements of the dielectric relaxation and the water activity in its aqueous solutions. Dielectric relaxation spectra in the frequency domain were obtained from time domain reflectometry. The dielectric relaxation time was then determined by fitting the spectra to a Cole-Cole type equation and used to evaluate the average hydration number representing the average number of water molecules forming a complex with a sugar molecule at infinite dilution. The concentration dependence of the dielectric relaxation time in aqueous solutions of all examined sugars generated a single master cur ve. The average hydration number of psicose was found to be identical with that of fructose. Only slight differences were noticeable among the concentration dependences of the water activity of monosaccharides. The equilibrium constant of hydration of sugar was calculated by considering material balances in an aqueous solution of sugar and using experimentally obtained values of the average hydration number and the water activity. The equilibrium constant values increased in the order of glucose < fructose ≈ psicose < trehalose < sucrose < maltose. The present results suggest that both fructose and psicose interact with water in a similar manner.

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“…It is, therefore, of some interest to learn about the properties of such solutions. Comprehensive experimental data for these systems are relatively scarce; [12][13][14][15] therefore, we report the dielectric spectra for solutions of these three compounds at concentrations ranging from Cϭ0.01 to 1 mol dm Ϫ3 . The results are discussed in a threefold manner.…”

Section: Introductionmentioning

confidence: 99%

Dielectric spectroscopy in aqueous solutions of oligosaccharides: Experiment meets simulation

Weingärtner

Knocks

Boresch

et al. 2001

The Journal of Chemical Physics

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We report the frequency-dependent complex dielectric permittivity of aqueous solutions of the homologous saccharides D(+)-glucose, maltose, and maltotriose in the frequency range 200 MHz⩽ν⩽20 GHz. For each solute, solutions having concentrations between 0.01 and 1 mol dm−3 were studied. In all measured spectra two dispersion/loss regions could be discerned. With the exception of the two most concentrated maltotriose solutions, a good description of the spectra by the superposition of two Debye processes was possible. The amplitudes and correlation times of the glucose and maltose solutions determined from fits of the experimental data were compared to those obtained in an earlier molecular dynamics study of such systems; the overall agreement between experiment and simulation is quite satisfactory. A dielectric component analysis of the simulation results permitted a more detailed assignment of the relaxation processes occurring on the molecular level. The physical picture emerging from this analysis is compared with traditional hydration models used in the interpretation of measured dielectric data. It is shown that the usual standard models do not capture an important contribution arising from cross terms due to dipolar interactions between solute and water, as well as between hydration water and bulk water. This finding suggests that conventional approaches to determine molecular dipole moments of the solutes may be problematic. This is certainly the case for solutes with small molecular dipole moments, but strong solute–solvent interactions, such as the saccharides studied here.

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Dielectric Relaxation of Aqueous Solution with Low-molecular-weight Nonelectrolytes and Its Relationship with Solution Structure

Cited by 28 publications

References 7 publications

Effect of water potential on sol–gel transition and intermolecular interaction of gelatin near the transition temperature

Effect of water potential on sol–gel transition and intermolecular interaction of gelatin near the transition temperature

Dielectric Relaxation and Water Activity in Aqueous Solution of D-Psicose

Dielectric spectroscopy in aqueous solutions of oligosaccharides: Experiment meets simulation

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