Analytical Sciences

Development of Tetrahydrofuran/Water Optical Waveguide and Its Application to the Observation of Extraction Behavior of 1-Anilino-8-naphtalene Sulfonate at the Tetrahydrofuran/Water Interface

Hiromi TAKIGUCHI,*1 Soto ASANUMA,*2 Junya KAMIYAMA,*2 Hiroyasu MURATA,*2 Yuki HASEGAWA,*2 Satoshi YOSHIZAWA,*2 Hiroki HOTTA,*3 Tamao ODAKE,*1 Tomonari UMEMURA,*4 Kiichi SATO,*2 and Kin-ichi TSUNODA*2

*1 Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
*2 Department of Chemistry and Chemical Biology, Gunma University, 1-5-1 Tenjin-cho, Kiryu 376-8515, Japan
*3 Graduate School of Maritime Sciences, Kobe University, 5-1-1 Fukae-minamimachi, Higashinada, Kobe 658-0022, Japan
*4 School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji 192-0392, Japan

A stable two-phase sheath flow using tetrahydrofuran (THF) for an inner flow and water for an outer flow was formed in a glass capillary, and worked as a stable liquid-core/liquid-cladding optical waveguide (THF/water LLW). Although THF and water were miscible with any ratio, the length of the stable THF/water LLW at 0.9 – 2.1 cm s⁻¹ reached at least 150 mm. The THF/water LLW was applied to the observation of extraction behavior of solvatochromic fluorescence dye, 1-anilino-8-naphtalene sulfonate (ANS), through the THF/water interface. ANS was added to the water phase (clad solution) and its fluorescence, which was excited with the guided light (355 nm) through the LLW, was observed by changing the position of the detector. While the ANS stayed in the region of 70% THF to the end of the LLW without the addition of cationic surfactant, hexadecyltrimethylammonium ion (CTA⁺) at pH 3 and 11, the ion-pair of ANS and CTA⁺ was extracted into the higher concentration region of THF with the addition of CTA⁺ at pH 11.

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