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Kosuke Izutsu - One of the best experts on this subject based on the ideXlab platform.
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Further Study on the Component Related to Ion Solvation of the Liquid Junction Potential between Electrolyte Solutions in Different Solvents
Bulletin of the Chemical Society of Japan, 2013Co-Authors: Kosuke IzutsuAbstract:The Liquid Junction Potential between electrolyte solutions in different solvents has been studied, paying attention to why the values of the component related to ion solvation are actually much sm...
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Liquid Junction Potentials between electrolyte solutions in different solvents.
Analytical sciences : the international journal of the Japan Society for Analytical Chemistry, 2011Co-Authors: Kosuke IzutsuAbstract:Many chemists are not familiar with the problem of the Liquid Junction Potential (LJP) between electrolyte solutions in different solvents. Some even misunderstand it. Therefore, it seems worthwhile to write a review article on this subject. The LJP between electrolyte solutions in different solvents consists of three components: i.e., (a) a component related to electrolyte concentrations and ionic mobilities, (b) a component related to ion solvation (and ionic mobilities), and (c) a component related to solvent-solvent interactions. The characteristics of each of the three components have been discussed in detail, based on our old and new results. Components (a) and (b) are diffusion Potentials but component (c) is a dipole Potential.
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Liquid Junction Potential between different solvents the component due to solvent solvent interactions is dipole Potential in nature
Bulletin of the Chemical Society of Japan, 2010Co-Authors: Kosuke IzutsuAbstract:The Liquid Junction Potential between different solvents contains three components, i.e., component (a) due to electrolyte concentrations and ionic mobilities, component (b) due to the solvation of ions, and component (c) due to solvent-solvent interactions. The values of component (b) are actually much smaller than the values calculated from theoretical equations, but other researchers considered the equation to be valid and came to the conclusion that component (c) depended on electrolytes. From electrolyte-independent characteristics and others, we report here that component (c) is not the diffusion Potential but the dipole Potential.
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Liquid Junction Potential between electrolyte solutions in different solvents some consideration on the component due to solvent solvent interactions
Bulletin of the Chemical Society of Japan, 2010Co-Authors: Kosuke IzutsuAbstract:The Liquid Junction Potential between different solvents contains three components, i.e., (a) related to ionic concentrations and mobilities, (b) related to ion solvations, and (c) related to solvent-solvent interactions at the Junction. In order to understand the characteristics of component (c), we formerly introduced a model that the two solvents at the Junction directly interact each other as a Lewis acid and a Lewis base and some parts of the solvent molecules are oriented perpendicularly to the boundary. However, this direct-interaction model deviates from reality in that the actual Junction has a transition layer; its solvent composition gradually varies from that on one side to that on the other and its thickness expands with time, usually between 0.05 and 1 mm. In this report, we show that this direct-interaction model is applicable also in the presence of such transition layer. For this, we divide the transition layer in steps and get the total component (c) by summing up component (c) at each step. Here, the value at each step is obtained from the experimental results for component (c) at mixed solvent/mixed solvent Junctions. The extent of the solvent orientation at the boundary was also roughly estimated.
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Liquid Junction Potential between Electrolyte Solutions in Different Solvents Studied by Use of Mixed Solvent/Pure Solvent Junctions
Bulletin of the Chemical Society of Japan, 2008Co-Authors: Kosuke IzutsuAbstract:Of the three components of the Liquid Junction Potential between electrolyte solutions in different solvents, the component due to the interaction between different solvents (component (c)) was stu...
Takashi Kakiuchi - One of the best experts on this subject based on the ideXlab platform.
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Single-ion activity: a nonthermodynamically measurable quantity
Journal of Solid State Electrochemistry, 2020Co-Authors: Takashi KakiuchiAbstract:Ionic Liquid salt bridge (ILSB) that effectively minimizes the Liquid Junction Potential in a galvanic cell articulates the nonthermodynamic measurability of single-ion activity. Points for further improvement of the stability of ILSB are summarized, and associated intriguing phenomena at the ILSB-W interface are described.
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determination of single ion activity coefficients of hydrogen and bromide ions in aqueous hydrobromic acid solutions based on an ionic Liquid salt bridge
Electrochimica Acta, 2013Co-Authors: Kazuya Minami, Takashi KakiuchiAbstract:Abstract Single ion activity coefficients of H+ and Br− in aqueous hydrobromic acid solutions, γ H + and γ Br − , have been estimated potentiometrically at 25 °C with a hydrogen electrode and a silver–silver bromide electrode, respectively, based on the assumption that the change in the Liquid Junction Potential at the interface between a sample solution and an ionic Liquid salt bridge is negligibly small. The mean activity coefficients of HBr calculated from experimentally obtained values of γ H + and γ Br − well agree with the literature values over the entire concentration ranges studied, 1.04 × 10−3 to 0.528 mol kg−1. Overall dependencies of γ H + and γ Br − on ionic strength are similar to those found previously in aqueous HCl solutions, but the degree of the dependence is distinctively stronger in both γ H + and γ Br − . Plots of γ H + and γ Br − as a function of the ionic strength are nearly congruent with the predictions by Fraenkel's smaller-ion shell (SiS) model up to 0.05 mol kg−1. However, with a further increase in HBr concentration experimental γ H + and γ Br − more rapidly increases and decreases, respectively, in comparison with the SiS predictions.
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ionic Liquid salt bridge with low solubility of water and stable Liquid Junction Potential based on a mixture of a Potential determining salt and a highly hydrophobic ionic Liquid
Analytical Chemistry, 2012Co-Authors: Limin Zhang, Yuki Kitazumi, Takahiro Miyazawa, Takashi KakiuchiAbstract:A new type of ionic Liquid salt bridge(ILSB) based on a mixture of pentyltripropylammonium bis(pentafluoroethanesulfonyl)amide, [N3335+][C2C2N–], and heptadecafluorodecyltrioctylphosphonium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, [TOPH+][TFPB–], shows a stable phase-boundary Potential (ΔILWϕ) between the ILSB and an aqueous solution of MCl (M = H+, Li+, Na+, and K+) over the concentration range from 0.05 mM to 0.5 M with an averaged excursion in 1 h of ±0.3 mV. The reproducibility of ΔILWϕ is ±0.6 mV on average (95% confidence interval) in KCl solutions in this concentration range. The mixing of the two different types of salts not only increases the stability of the phase-boundary Potential but provides us with more freedom in selecting Potential-determining salts to design and customize ILSBs for different purposes.
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Ionic Liquid salt bridge based on tributyl(2-methoxyethyl)phosphonium bis(pentafluoroethanesulfonyl)amide for stable Liquid Junction Potentials in highly diluted aqueous electrolyte solutions.
Talanta, 2010Co-Authors: Hideaki Sakaida, Yuki Kitazumi, Takashi KakiuchiAbstract:A moderately hydrophobic ionic Liquid, tributyl(2-methoxyethyl)phosphonium bis(pentafluoroethanesulfonyl)amide ([TBMOEP+][C2C2N−]), shows a very stable Liquid Junction Potential upon contact with an aqueous solution whose ionic strength is as low as 1 μmol dm−3. The stability with the maximum excursion of the Potential within ±0.5 mV for 30 min is very promising for accurate determination of pH and other single ion activities potentiometrically.
Yutaka Aoki - One of the best experts on this subject based on the ideXlab platform.
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Liquid Junction Potential between different solvents. A Junction with an alkali metal salt as electrolyte
Journal of Electroanalytical Chemistry, 1992Co-Authors: Kosuke Izutsu, Toshio Nakamura, Yutaka AokiAbstract:Abstract The characteristics of the three components of a Liquid Junction Potential between different solvents were studied at a Junction with an alkali metal salt as the electrolyte. As for a Junction with a tetraalkylammonium salt as the electrolyte, the equation previously reported for component (a) was proved to be valid in many cases. Component (b) at H 2 O/organic solvent and MeOH/dipolar aprotic solvent Junctions also behaved similarly to that at a Junction with a tetraalkylammonium salt. At Junctions between aprotic solvents, however, lithium and sodium ions did not make an appreciable contribution to component (b), even when this was expected theoretically. This fact was found to be the cause of the apparently different behavior of component (c) in the case of salts of these metal ions. Thus component (c) can be considered to be almost independent of electrolyte species and concentrations, even when alkali metal salts are used as the electrolyte.
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Liquid Junction Potential between different solvents: A Junction with different electrolytes on the two sides
Journal of Electroanalytical Chemistry, 1992Co-Authors: Kosuke Izutsu, Mitsuo Muramatsu, Yutaka AokiAbstract:Abstract The characteristics of the Liquid Junction Potential (ljp) between different solvents were investigated using different electrolytes on the two sides of a Junction, denoted as c 1 MX(S 1 )| c 2 NY(S 2 ). The ljp consists of three components, a, b and c, as reported previously. The calculated values of components a and b were obtained by numerical integration of the following equations, E j (a) = ( − RT / F )∫ S 1 S 2 {( t M – t X ) d ln a MX + ( t N – t Y ) d ln a NY} E j (b) = ( − 1 / F )∫ S 1 S 2 {itt M dμ°(M) – t X dμ°(X) + t N dμ°(N) – t Y dμ°(Y)} where t are the ionic transport numbers, a the electrolyte activities, and μ° the standard chemical Potentials. Linear variations in t, a and μ° at the interphase region were assumed. In a cell containing the above Junction, when the electrolyte concentrations, c 1 and c 2 , are varied, components a and b vary simultaneously. However, by making a proper correction for the actual values of component b, the emf variation corresponding to the actual variation in component a could be obtained. Thus, the above equation for component a was confirmed to be valid. The results also suggest that the previously reported method of estimation of component b is reasonable.
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a new method of estimation of the Liquid Junction Potential between different solvents
Analytical Sciences, 1991Co-Authors: Kosuke Izutsu, Toshio Nakamura, Mitsuo Muramatsu, Yutaka AokiAbstract:Based on the experimental study of the three components of the Liquid Junction Potential (LJP) between different solvents, a new method was developed for the estimation of the LJP. In the method, each of the three components was estimated separately from the others, and then they were summed up. The results obtained by this method agreed well with the results obtained by the conventional method.
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Liquid Junction Potential between different solvents: Component due to the differences in electrolyte concentrations and ionic mobilities
Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1991Co-Authors: Kosuke Izutsu, Toshio Nakamura, Mitsuo Muramatsu, Yutaka AokiAbstract:Abstract Among the three components of the Liquid Junction Potential at a Junction between different solvents, the component due to the differences in electrolyte concentrations (or activities) on the two sides of the Junction and the differences between the cationic and anionic mobilities was investigated. An equation was derived for the component at a Junction with the same electrolyte (MX) on the two sides, where t represents the ionic transport numbers and a the electrolyte activity. Linear variations of t and a were assumed at the interphase region of the Junction. The equation was confirmed experimentally to be approximately valid in many cases and may be used in estimating the component. In some cases, apparent deviations from the equation were observed. The deviations were attributed to the influence of electrolyte concentration, which caused partial decreases in the component due to the solvent-solvent interactions at the Junction. Some theoretical and experimental studies were also carried out for a Junction with different electrolytes (MX and NY) on the two sides,
C. Kalidas - One of the best experts on this subject based on the ideXlab platform.
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Gibbs Energies of Solvation and Solvent Transport of Some Silver(I) Salts in Water + N-Methyl-2-pyrrolidinone at 30 .degree.C
Journal of Chemical & Engineering Data, 1995Co-Authors: T. K. Varadarajan, R. Parvathy, T. V. Ramakrishna, C. KalidasAbstract:The preferential solvation of the silver salts silver(I) bromate, iodate, sulfate, and oxalate in the binary solvent mixtures of water and N-methyl-2-pyrrolidinone has been studied by solubility and solvent transport number measurements. The Gibbs transfer energies of the salts from water to water + N-methyl-2-pyrrolidinone mixtures, calculated from solubility data, were split into their ionic values by using the transfer energies of silver ion determined on the basis of the negligible Liquid Junction Potential method. These data have also been compared with those obtained on the basis of the tetraphenylarsonium tetraphenylborate method. Solvent transport numbers (Δ') of N-methyl-2-pyrrolidinone were determined for all the salts by employing a concentration cell with transference as suggested by Wagner. The results have been interpreted in terms of heteroselective solvation of all the salts, with silver ion being selectively solvated by N-methyl-2-pyrrolidinone and anions by water.
Juan Manuel Madariaga - One of the best experts on this subject based on the ideXlab platform.
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Determination of ion exchange equilibrium constants of strongly acidic resins with alkaline-earth metals by means of the potentiometric titrations technique.
Talanta, 1999Co-Authors: Gregorio Borge, Gorka Arana, Luis Fernández, Juan Manuel MadariagaAbstract:Abstract A recently developed methodology for the determination of ion exchange equilibrium constants has been applied to ion exchange systems of 1:2 stoichiometry. Potentiometric titrations with variable ionic strength were carried out. Ionic medium titrations were performed for the estimation of the Liquid Junction Potential. The modified Bromley's methodology and the Wilson model were used for the estimation of the activity coefficients of the species in the aqueous and resin phase, respectively. A modification of the Henderson equation is used for the estimation of Liquid Junction Potentials in the mixtures including 1:2 electrolytes. Equilibrium constants for the H + /M 2+ (M=Mg, Ca, Sr and Ba) exchange systems in the strongly acidic resins Dowex CM-15 and Dowex C650 were studied.
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On the Liquid Junction Potential for the determination of equilibrium constants by means of the potentiometric technique without constant ionic strength
Journal of Electroanalytical Chemistry, 1997Co-Authors: Gregorio Borge, Luis A. Fernāndez, Juan Manuel MadariagaAbstract:Abstract A modified method for the calculation of Liquid Junction Potentials based on the Henderson equation is proposed. The estimation of the activity coefficients and the conductivities is performed by means of the Modified Bromley Methodology [ G. Borge, R. Castano, M.P. Carril, M.S. Corbillon, J.M. Madariaga, Fluid Phase Equilibria 121 (1996) 85–98; G. Borge, N. Etxebarria, L.A. Fernandez, M.A. Olazabal, J.M. Madariaga, Fluid Phase Equilibria 121 (1996) 99–109. ] and the Extended Falkenhagen Equation [ A. De Diego, Conductivity of concentrated electrolytic solutions: study of the dependence with concentration and temperature, Ph.D. Thesis, University of the Basque Country, Bilbao, 1996. ]. The efficiency of the method has been tested in potentiometric titrations without constant ionic strength. Its applicability to potentiometric titrations with constant ionic strength is also discussed.