Analytical Sciences

Consecutive Sample Injection Analysis in Tube Radial Distribution Chromatography

Yusaku TAKAHASHI,* Kazushi NISHIMURA,* Kazuhiko TSUKAGOSHI,* Katsumi TSUCHIYA,* Ken HIROTA,* Kenichi YAMASHITA,** and Masaharu MURATA***

*Applied Chemistry, Graduate School of Science and Engineering, Doshisha University, Kyotanabe 610-0321, Japan
**Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 807-1 Shuku-machi, Tosu 841-0052, Japan
***Department of Advanced Medical Initiatives, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka 812-8582, Japan

Tube radial distribution chromatography based on the tube radial distribution flow, or annular flow, in an open-tubular capillary has been reported, where the annular flow is created through phase-separation multiphase flow. We have proposed the first-ever procedure for consecutive sample injection analysis using chromatography. In basic terms, a commercially available HPLC system could be used with a sample injector (0.2 μL volume) and a fused-silica capillary tube (250 cm long) as a separation column instead of a normal packed one, while the built-in detection cell was replaced by improved on-capillary detection. A ternary mixed solution of water/acetonitrile/ethyl acetate (3:8:4 volume ratio) was delivered into the capillary tube as an eluent at a flow rate of 2.0 μL min⁻¹. Model sample solutions of 1-naphthol and 2,6-naphthalenedisulfonic acid were consecutively analyzed by the present chromatography with a processing rate of 6 samples per hour. Simple and rapid consecutive analysis could be performed because washing and initialization of the separation tube was no longer necessary. The obtained results provide clues to developing new methodologies which combine features of both chromatography (separation) and the flow injection method (consecutive analysis).

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