Kitamura Noboru, Yamada Momoko, Ishizaka Shoji, Konno Kumiko
Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Anal Chem. 2005 Sep 15;77(18):6055-61. doi: 10.1021/ac050822k.
Thermal phase separation of aqueous triethylamine (TEA) solutions (TEA wt % = 6.5-6.7 in H2O) was induced by irradiating a focused 1064-nm laser beam (spot size approximately 1 mum) under an optical microscope, and this produced a single micrometer-sized TEA droplet as demonstrated by in situ Raman microspectroscopy. Since H2O absorbs 1064-nm light, heat is generated at the focal spot of the incident laser beam, giving rise to photothermal phase separation of the aqueous TEA solution. The TEA droplet produced by phase separation was trapped simultaneously by the incident laser beam. In the presence of p-chlorophenol (CP) in an aqueous TEA solution, laser-induced photothermal phase separation and simultaneous TEA droplet formation brought about extraction/concentration of CP from the surrounding solution phase to the TEA droplet (approximately 15-mum diameter and 1.7-pL volume). Raman microspectroscopy demonstrated that the distribution coefficient of CP (KD) between the solution phase and the single TEA droplet was KD(drop) = approximately 21, while that in a bulk TEA/H2O system was KD(bulk) = 4.7. The larger KD(drop) value as compared to KD(bulk) was discussed in terms of radiation pressure exerted on CP in the TEA droplet.
通过在光学显微镜下照射聚焦的1064纳米激光束（光斑尺寸约为1微米），引发了三乙胺（TEA）水溶液（水中TEA重量百分比=6.5 - 6.7）的热相分离，原位拉曼显微光谱表明这产生了单个微米级的TEA液滴。由于水吸收1064纳米光，在入射激光束的焦点处产生热量，从而导致TEA水溶液的光热相分离。相分离产生的TEA液滴同时被入射激光束捕获。在TEA水溶液中存在对氯苯酚（CP）的情况下，激光诱导的光热相分离以及同时形成的TEA液滴使得CP从周围的溶液相萃取/浓缩到TEA液滴中（直径约15微米，体积1.7皮升）。拉曼显微光谱表明，CP在溶液相和单个TEA液滴之间的分配系数（KD）为KD（液滴）≈21，而在大量TEA/H₂O体系中为KD（大量）=4.7。针对与KD（大量）相比更大的KD（液滴）值，从TEA液滴中施加在CP上的辐射压力方面进行了讨论。
