Abstract
When homogeneous solutions that feature two-phase separation properties, such as a ternary mixed solvent solution of water-acetonitrile-ethyl acetate, are fed into a microspace, such as a capillary tube and a microchannel, the solvent molecules are radially distributed into the microspace, generating inner and outer phases. This is called “tube radial distribution phenomenon” (TRDP). In this study, microflow extraction for the Fe(III)-8-hydroxyquinoline complex was carried out using a microchip incorporating microchannels based on the TRDP. A microchip in which one wide channel was separated into three narrow channels was designed and manufactured. When the ternary mixed solvent solutions of water (acetic acid aqueous solution, pH3.5)-acetonitrile-ethyl acetate (volume ratio 40:45:15) containing Fe(III) and 8-hydroxyquinoline were fed into the wide channel under laminar flow conditions, the solvent molecules were radially distributed in the channel, generating inner (organic solvent-rich) and outer (water-rich) phases. The Fe(III)-8-hydroxyquinoline complex in the carrier solution was distributed between the inner and outer phases due to its hydrophilic nature, and then collected through the three narrow channels. The concentration of Fe(III) in the center narrow channel was greater than those in the two outer narrow channels through extraction with 8-hydroxyquinoline.
