Analytical Sciences

Tube Radial Distribution Chromatography on a Microchip Incorporating Microchannels with a Three-to-One Channel Confluence Point

Naomichi SUZUKI,* Kenichi YAMASHITA,*** Hideaki MAEDA,*** Masahiko HASHIMOTO,* and Kazuhiko TSUKAGOSHI*,**

*Department of Chemical Engineering and Materials Science, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
**Tube Radial Distribution Phenomenon Research Center, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
***Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 807-1 Shuku-machi, Tosu, Saga 841-0052, Japan

We developed a capillary chromatography system using a phase-separated solvent mixture as a carrier solution—i.e., a water-hydrophilic/hydrophobic organic solvent mixture—which we call “tube radial distribution chromatography” (TRDC). Here, we attempted to apply the TRDC system to a microchip incorporating microchannels with a double T-junction for injection of analyte solution and a three-to-one, narrow-to-wide channel confluence point for tube radial distribution phenomenon (TRDP) at room temperature. A ternary mixed solvent of water, acetonitrile and ethyl acetate was used as a carrier solution. TRDP in the wide microchannel was examined using various flow rates, temperatures, and component solvent ratios. Successful observation was carried out using a fluorescence microscope-CCD camera. Model analytes perylene (hydrophobic) and Eosin Y (hydrophilic) were separated by flowing through the microchannel, without any treatment such as packed columns or coating, at room temperature (25°C).

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