Chromatographic study on liquid‐phase adsorption on octadecylsilyl‐Silica Gel

External and Intraparticle Diffusion of Coumarin 102 with Surfactant in the ODS-silica Gel/water System by Single Microparticle Injection and Confocal Fluorescence Microspectroscopy

“…[1][2][3][4] The mass transfer in the porous material/solution system has been often analyzed in terms of diffusion in pores of the material. [5][6][7][8][9][10] However, analysis of the mass transfer mechanism is generally difficult. As an example, mass transfer in a porous particle/ solution system consists of several elementary processes such as adsorption/desorption at the pore walls, mass transfer in the surrounding solution (external mass transfer), and diffusion in the pore solution (pore diffusion) and along the pore walls (surface diffusion).…”

“…Direct measurements of the individual elementary processes are necessary for the analysis of the mass transfer mechanism in the porous material/solution system. 5,6,9,11,12 Mass transfer of a dye between a porous microparticle and the surrounding solution phase was analyzed by single microparticle injection and absorption microspectroscopy. 6,13 In the single microparticle/solution system, external mass transfer between the microparticle and the bulk solution is steady-state spherical diffusion so that analysis of the external mass transfer is simplified.…”

Analysis of Distribution and Intraparticle Diffusion of a Fluorescent Dye in Mesoporous Silica Gel by Confocal Fluorescence Microspectroscopy

“…High functionality of the porous material is caused by a high specific surface area, interaction between a solute and adsorption sites of the pore walls, effective mass transfer of the solute in the pores, and so forth. [1][2][3] Quantitative analyses of adsorption/desorption and reaction at solid/liquid interfaces, diffusion in the pore solution (pore diffusion) and at the pore walls (surface diffusion), and mass transfer of the solute between the material surface and the bulk solution phase (external mass transfer) in porous material/ solution systems have been demonstrated by chromatographic analysis for a large number of microparticles, 4,5 microspectroscopic analysis for individual microparticles, [6][7][8][9][10][11] and so on. [12][13][14] Nonetheless, detailed consideration will be required for analysis of individual elementary processes because various processes are included in the porous material/solution systems.…”

The Hydroxyl Group-Solvent and Carbonyl Group-Solvent Specific Interactions for Some Selected Solutes Including Positional Isomers in Acetonitrile/Water Mixed Solvents Monitored by HPLC

“…The thermodynamic relationship between the capacity factor (k') and temperature (T) was used to obtain solute transfer enthalpies and entropies and is as follows [1][2][3][4][5][6][7][8][9][10] :…”

“…The chromatographic enthalpies and entropies for the solute transfer from the mobile to the stationary phase can be obtained by measuring retention data over a wide range of temperature [1][2][3][4][5][6][7][8][9][10][11][12] and the specific solute functional group-mobile phase interaction can be derived from such thermodynamic data. [13][14][15][16][17] In our previous studies, we measured the specific hydroxyl group-solvent and carbonyl group-solvent interaction enthalpies and entropies of phenol and acetophenone in aqueous methanol mixtures using the squalane-impregnated C 18 stationary phase, 13 the specific functional group-solvent interaction enthalpies and entropies of phenol, benzylalcohol, phenenthylalcohol, acetophenone, and benzylacetone in aqueous acetonitrile mixtures using the squalane-impregnated C 18 stationary phase, 16 and the specific functional group-solvent interaction enthalpies and entropies of 4 positional isomers of phenylbutanol, 5-phenyl-1-pentanol, 3 positional isomers of alkylarylketone derived from butylbenzene, and 1-phenyl-2-hexanone in aqueous methanol mixtures using the Alltima C 18 stationary phase.…”