Thermodynamic Characteristics of Surface Diffusion in Reversed-Phase Liquid Chromatography

and, Kanji Miyabe†; Guiochon, Georges

doi:10.1021/jp991725w

Cited by 45 publications

(93 citation statements)

References 41 publications

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“…On the basis of these results, we proposed a surface-restricted molecular diffusion model for surface diffusion as a first approximation of the mechanism of surface diffusion and tried to consistently explain some intrinsic characteristics of surface diffusion. [24][25][26][27][28][29][30] The semi-logarithmic plots between the ratios DLs/Dm and Ds/Dm and -Qst in Fig. 6 fluctuate around a single straight line, although there is some scatter.…”

Section: Mechanism Of Surface Diffusionmentioning

confidence: 90%

Peak Parking-Moment Analysis Method for the Measurement of Surface Diffusion Coefficients

2009

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The peak parking (PP)-moment analysis (MA) method was applied to the measurement of surface diffusion coefficients (Ds) in reversed-phase liquid chromatography using a C18-silica gel and an aqueous solution of methanol (70 vol%). The values of Ds measured by the PP-MA method were in agreement with those obtained by the pulse response (PR)-MA method, which is one of powerful strategies for the quantitative study on the mass transfer kinetics in columns and stationary phases. It was demonstrated that the PP-MA method is an alternative for the experimental measurement of Ds. The mechanism of surface diffusion was considered on the basis of molecular diffusion by introducing a restriction energy (Er) for surface diffusion. Physical meanings of Er were discussed by analyzing the correlation between the enthalpy change due to sample retention (Qst) and Ds. It seems that surface diffusion of a sample molecule is restricted by its retention strength and by the solvent structure formation due to the hydrophobic solvation of the stationary phase surface.

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Section: Mechanism Of Surface Diffusionmentioning

confidence: 90%

Peak Parking-Moment Analysis Method for the Measurement of Surface Diffusion Coefficients

2009

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“…Physical meaning of the activation energy of surface diffusion Figure 8 shows the correlation between E s and Q st for two homologous series [48]. For both series, E s increases almost linearly with increasing -Q st but is not equal to zero at Q st = 0.…”

Section: 33mentioning

confidence: 99%

Measurement of the parameters of the mass transfer kinetics in high performance liquid chromatography

Miyabe

Guiochon²

2003

J of Separation Science

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148

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Fundamental studies of the mass transfer kinetics are as essential as those of the retention equilibrium for a detailed understanding of the characteristics and the mechanisms of chromatographic separations. The acquisition of a large amount of reliable experimental data and of meaningful results is necessary for any further progress of our knowledge of kinetics. The main goal of this review is to provide information on the methods used to perform accurate measurements and on the data analysis procedures used for deriving the kinetic parameters characterizing mass transfer in HPLC. First, the general characteristics of several methods of determination of some kinetic parameters are briefly reviewed. Secondly, we give detailed explanations of the experimental conditions of the pulse on a plateau method (i.e., elution chromatography on a plateau of finite concentration or pulse response method) and of the data analysis procedures based on moment analysis. Thirdly, we explain some important requirements for the acquisition of appropriate experimental data and discuss corrections to be applied when deriving several kinetic parameters. Fourthly, we discuss the accuracy of the kinetic parameters derived from the pulse on a plateau method and from moment analysis. Finally, some results concerning the mass transfer kinetics in RPLC systems are demonstrated as examples.

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“…This result suggests that there may be a kind of intimate correlation between surface diffusion and molecular diffusion [24]. From these observations, K. M. and Guiochon have proposed a surface-restricted molecular diffusion model as a first approximation for the mechanism of surface diffusion [16,[23][24][25][28][29][30][31] and formulated the new model on the basis of the absolute rate theory [32]. On the other hand, in In Fig.…”

Section: Dependence Of C S D S On Retention Strengthmentioning

confidence: 99%

“…Additionally, K. M. and Guiochon [16,17,23,26,[29][30][31][33][34][35][36][37] have shown that an EEC is also established for surface diffusion in RPLC under various conditions of sample compounds and stationary and mobile phases. They analyzed some thermodynamic data concerning the retention equilibrium and surface diffusion in more detail on the basis of the four approaches proposed by Krug et al [38][39][40] and strictly demonstrated the establishment of the extra-thermodynamic relationship, i. e., EEC, for both the retention equilibrium and surface diffusion in RPLC [30,31,33,34,37,41].…”

Section: Extra-thermodynamic Properties Of D Lsmentioning

confidence: 99%

A kinetic parameter concerning mass transfer in silica monolithic and particulate stationary phases measured by the peak‐parking and slow‐elution methods

Miyabe

Kobayashi

Tokuda

et al. 2006

J of Separation Science

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Mass transfer in monolithic C18-silica stationary phases and C18-silica gel particles was studied. A traditional kinetic parameter, gamma(s)D(s), which is a diffusion coefficient of solute molecules in the stationary phase, was measured by two unusual approaches, i.e., peak-parking and slow-elution methods. The correlation between the ratio of gamma(s)D(s) to molecular diffusivity (Dm) and the retention factor (k) was represented by one common curve, irrespective of the RPLC conditions. A similar curved profile was also observed between another kinetic parameter (D(Ls)), which is related to the axial diffusive molecular migration in the stationary phase, and the retention equilibrium constant (Ka). The values of D(Ls) and Ka were calculated from those of gamma(s)D(s) and k, respectively. The ratio of D(Ls)/Dm increases with decreasing Ka and seems to approach around unity when Ka is infinitely small. The dependence of D(Ls) on Ka was also studied from extra-thermodynamic points of view. The linear correlation between In D(Ls) and In Ka suggests the existence of a kind of linear free energy relationship between the mass transfer in the stationary phase and the retention equilibrium. Because these characteristics of D(Ls) are similar to those of the surface diffusion coefficient (D(sur)), D(Ls) seems to correspond to D(sur).

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Thermodynamic Characteristics of Surface Diffusion in Reversed-Phase Liquid Chromatography

Cited by 45 publications

References 41 publications

Peak Parking-Moment Analysis Method for the Measurement of Surface Diffusion Coefficients

Peak Parking-Moment Analysis Method for the Measurement of Surface Diffusion Coefficients

Measurement of the parameters of the mass transfer kinetics in high performance liquid chromatography

A kinetic parameter concerning mass transfer in silica monolithic and particulate stationary phases measured by the peak‐parking and slow‐elution methods

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