Open AccessKinetic Analysis of Distribution of Weak Acid in an Oil-Gelatin Microcapsule/Water System Studied by Microcapillary Injection and Microabsorption Methods
Author(s) -
Kiyoharu Nakatani,
Y. Kobayashi,
Hiroshi Kakizaki
Publication year - 2004
Publication title -
analytical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 73
eISSN - 1348-2246
pISSN - 0910-6340
DOI - 10.2116/analsci.20.1529
Subject(s) - chemistry , gelatin , dibutyl phthalate , mass transfer , membrane , anthracene , reaction rate constant , phthalate , chromatography , chemical engineering , kinetics , analytical chemistry (journal) , organic chemistry , biochemistry , physics , quantum mechanics , engineering
The distribution of anthracene-9-carboxylic acid across dibutyl phthalate/gelatin-membrane/water interface of a single microcapsule was analyzed using microcapillary manipulation and microabsorption methods. The partitioning ratio and the distribution rate in the microcapsule/water system were measured for various pH values in the water phase. Results were compared with those in the dibutyl phthalate/water system in the absence of the gelatin membrane. The distribution rate could be analyzed on the basis of a first-order type reaction. The observed rate constant was linearly proportional to the inverse of the microcapsule radius, indicating that the distribution rate is limited by interfacial mass transfer. Analysis of the pH dependence of the interfacial mass transfer rate suggests that the mass transfer of the neutral species of anthracene-9-carboxylic acid (AnH) competes with the ion transfer of the dissociated species (An-) at the liquid/liquid interface in the gelatin membrane of the microcapsule.