Evaluation of the Distribution in Mesopores of ODS-Silica Gel in Alcohol-Water Solvent by Absorption Microspectroscopy

Mass transfer of weak acid in nanometer-sized pores of octadecylsilyl-silica gel

“…In a silica gel/water system, we reported the relationship between the intraparticle diffusion coefficient and isotherm parameters, and nanometer pore size dependence of the intraparticle diffusion for the sorption of a cationic dye [13,14]. In an octadecylsilyl (ODS)-silica gel/organic solventwater system, the microscopic polarity near the ODS/solution interface has been reported for the sorption of a neutral solute [15,16]. In the present article, the sorption of a weak acid into single ODS-silica gel microparticles, used as a separation medium in liquid chromatography and solid-phase extraction, was analyzed using the microcapillary injection-manipulation and absorption microspectroscopy.…”

Effect of Organic Solvent on the Mass Transfer Mechanism of Coumarin 102 in a Single Octadecylsilyl Silica Gel/Organic Solvent–Water System by Laser Trapping and Fluorescence Microspectroscopy

“…In this study, we discovered that both pore and surface diffusions of C102 occurred in the BuOH solution, whereas ACN and DMF solutions only caused surface diffusion. The relative permittivities of ACN, DMF, and BuOH are 36.0, 36.8, and 17.1, respectively, indicating that ACN and DMF exhibit similar polarities. , Liquid chromatography and molecular dynamics simulation revealed that ACN formed a concentrated liquid phase at the ODS phase/bulk solution interface. − However, BuOH is distributed in the ODS phase and therefore does not form an interfacial liquid phase . Therefore, we concluded that the absence of pore diffusion in the ACN solution is due to the formation of the interfacial liquid phase.…”

“…28,29 Even at low concentrations of 0.1 vol %, BuOH reduces solute adsorption by partitioning solvent molecules within the ODS alkyl chain. 31 Fluorescence microspectroscopy was used to measure C102 intraparticle diffusion in the ODS silica gel particles in these organic solvent−water solutions. We examined the effect of interfacial properties on mass transfer within pores using a pore and surface diffusion model.…”

“…Although the formation of an interfacial liquid phase has not been reported for DMF, we aimed to assess its effect by comparing it to ACN, given their similar polarities. Notably, BuOH does not form an interfacial liquid phase because it distributes throughout the ODS alkyl chain. , Even at low concentrations of 0.1 vol %, BuOH reduces solute adsorption by partitioning solvent molecules within the ODS alkyl chain . Fluorescence microspectroscopy was used to measure C102 intraparticle diffusion in the ODS silica gel particles in these organic solvent–water solutions.…”

Release Mechanism from a Microsphere of a Silkworm Chitin Derivative Studied by Single Microparticle Injection and Absorption Microspectroscopy

“…16 In homogeneous water, ethylene glycol, or methanol, the absorption maximum (lmax) of phenol blue was 658, 633, or 609 nm, respectively. 17 The lmax of the dye adsorbed on ODS groups on the mesopore walls of the ODSsilica gel in water was 626 nm. 18 As can be seen in Fig.…”