title: Mass transfer of weak acid in nanometer-sized pores of octadecylsilyl-silica gel.
abstract: The sorption of bromophenol blue or anthracene-9-carboxylic acid as a weak acid into single octadecylsilyl (ODS)-silica gel microparticles in a solution was analyzed by microcapillary injection-manipulation and absorption microspectroscopy. The distribution ratio and the sorption rate were highly dependent on the pH of the solution. These results are discussed in terms of the acid dissociation/association, distribution between the ODS and solution phases, and intraparticle diffusion of the weak acid in the nanometer-sized pores of the ODS-silica gel.
authors.affiliation: Department of Chemistry, Graduate School of Pure and Applied Sciences, University of Tsukuba, Ibaraki 305-8571, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kakizaki
authors.forename: Chiaki
authors.initials: C
authors.lastname: Aonuma
authors.forename: Kiyoharu
authors.initials: K
authors.lastname: Nakatani