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

Abstract

The release process of phenol blue from a dibutyrylchitin microsphere, prepared with chitin from a silkworm, into an aqueous solution was kinetically analyzed by single microparticle injection/manipulation and absorption microspectroscopy. The distribution ratio and the release rate of phenol blue in the single microsphere/water system were significantly influenced by the pH of the solution. These results are discussed in terms of the protonation of phenol blue and dibutyrylchitin, and the pore and surface diffusion in the pores of the microsphere.

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

“…[14][15][16] In those reports, as the mass transfer rate in the microparticle/solution system was assumed to be limited by the intraparticle diffusion, the intraparticle diffusion coefficient (Dp) was estimated. When the supposed Dp value was independent of the microparticle diameter (d), the intraparticle diffusion was analyzed in detail on the basis of the pore and surface diffusion model.…”

“…When the supposed Dp value was independent of the microparticle diameter (d), the intraparticle diffusion was analyzed in detail on the basis of the pore and surface diffusion model. [14][15][16] For mass transfer of perylene as a water-insoluble organic compound in the presence of Triton X-100 (nonionic surfactant) in an ODS-silica gel/water system, however, the supposed Dp value depended on d, indicating that the mass transfer rate cannot be analyzed as the intraparticle diffusion. 17 From the d dependence of mass transfer rate, we concluded that the rate-determining step was the micelle-mediated solubilization of the dye at the microparticle surface.…”

Mass Transfer of Water-insoluble Organic Compound from Octadecylsilyl-silica Gel into Water in the Presence of a Nonionic Surfactant

“…8,10,17 As the rate-determining step of the perylene release rate is assumed to be the intraparticle diffusion, the intraparticle diffusion coefficient of perylene or Triton X-100 (Do) was determined from A(t). The t dependence of the radial concentration profile in the microparticle (Cp(r,t)) is given by the spherical diffusion equation: ∂Cp(r,t)/∂t = Do{∂ 2 Cp(r,t)/∂r 2 + (2/r)∂Cp(r,t)/∂r}, where r is the radially directed spatial coordinate.…”

“…3,8,10,17 In these systems, the rate-determining step of the sorption or release was the intraparticle diffusion, and the intraparticle diffusion could be discussed on the basis of the pore and surface diffusion model. In the present paper, we report the release of perylene as a water-insoluble organic compound from single ODS-silica gel microparticles into the water phase in the presence of polyoxyethylene (10) octylphenyl ether (Triton X-100).…”