Kim H B, Hayashi M, Nakatani K, Kitamura N, Sasaki K, Hotta J, Masuhara H
Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060, Japan.
Anal Chem. 1996 Feb 1;68(3):409-14. doi: 10.1021/ac951058c.
Ion-exchange processes of a cationic dye (Rhodamine B; RhB) were studied for individual polymer particles (diameter of 16-20 μm) by laser trapping microspectroscopy and confocal fluorescence laser microspectroscopy. The absorbance of RhB at 565 nm adsorbed on a cation-exchange particle increased linearly with the concentration of RhB in the aqueous phase, while it was independent of the particle diameter. Fluorescence intensity profile measurements of RhB along the particle diameter by confocal fluorescence microspectroscopy directly proved that ion exchange took place in the surface layer (∼2-μm thickness) of the particle in the initial stage (1 h). Diffusion of RhB in the particle was very slow, and ion exchange proceeded gradually to the inner volume in the order of days. The ion-exchange processes were analyzed on the basis of simulation of the time course of the concentration profile of RhB in the particle, and the diffusion coefficient of RhB was determined to be (2-4) × 10(-11) cm(2)·s(-1).
通过激光捕获显微光谱法和共聚焦荧光激光显微光谱法，对单个聚合物颗粒（直径为16 - 20μm）上阳离子染料（罗丹明B；RhB）的离子交换过程进行了研究。吸附在阳离子交换颗粒上的RhB在565nm处的吸光度随水相中RhB浓度呈线性增加，而与颗粒直径无关。通过共聚焦荧光显微光谱法沿颗粒直径对RhB进行荧光强度分布测量，直接证明在初始阶段（1小时）离子交换发生在颗粒的表层（厚度约2μm）。RhB在颗粒中的扩散非常缓慢，离子交换按天数顺序逐渐向内部体积进行。基于对颗粒中RhB浓度分布随时间变化过程的模拟，对离子交换过程进行了分析，确定RhB的扩散系数为(2 - 4)×10(-11) cm(2)·s(-1)。
