Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Japan.
Langmuir. 2012 Nov 6;28(44):15428-32. doi: 10.1021/la302375z. Epub 2012 Oct 26.
The total internal reflection laser fluorescence microscope method was used to observe the lateral diffusion of a single octadecylrhodamine B (C(18)RB) molecule at the toluene-water interface. The interfacial diffusion constant of single fluorescent cation C(18)RB(+) was obtained from the maximum residence time in a small observation area with pH <2. For pH >3, the maximum residence time was remarkably shortened, indicating that single fluorescent zwitterion C(18)RB(±) rapidly converted to the nonfluorescent lactone at the interface. The lactonization rate was completed within 0.13 ms at the toluene-water interface but slowed to 67 ms at an interface saturated with dimyristoylphosphatidylcholine.
采用全内反射激光荧光显微镜方法观察了单个十八烷基罗丹明 B（C（18）RB）分子在甲苯-水界面的横向扩散。通过在 pH < 2 的小观察区域内获得的最大驻留时间，得到了单荧光阳离子 C（18）RB（+）的界面扩散常数。对于 pH > 3，最大驻留时间显着缩短，表明单荧光两性离子 C（18）RB（±）在界面处迅速转化为非荧光内酯。内酯化速率在甲苯-水界面上在 0.13 ms 内完成，但在充满二肉豆蔻酰磷脂酰胆碱的界面上减慢至 67 ms。
