Liquid membrane operations in a microfluidic device for separation of metal ions

Tatsuo Maruyama, Hironari Matsushita, Jun Ichi Uchida, Fukiko Kubota, Noriho Kamiya, Masahiro Goto

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130 Citations (Scopus)


A three-phase flow, water/n-heptane/water, was constructed in a microchannel (100-μm width, 25-μm depth) on a glass microchip (3 cm × 7 cm) and was used as a liquid membrane for separation of metal ions. Surface modification of the microchannel by octadecylsilane groups induced spontaneous phase separation of the three-phase flow in the microfluidic device, which allows control of interfacial contact time and off-chip analysis using conventional analytical apparatus. Prior to the selective transport of a metal ion through the liquid membrane in the microchannel, the forward and backward extraction of yttrium and zinc ions was investigated in a two-phase flow on a microfluidic device using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (commercial name, PC-88A) as an extractant. The extraction conditions (contact time of the two phases, pH, extractant concentration) in the microfluidic device were examined. These investigations demonstrated that the conventional methodology for solvent extraction of metal ions is applicable to solvent extraction in a microchannel. Finally, we employed the three-phase flow in the microchannel as a liquid membrane and observed the selective transport of Y ion through the liquid membrane. In the present study, we succeeded, for the first time, in the selective separation of a targeted metal ion from an aqueous feed solution to a receiving phase within a few seconds by employing a liquid membrane formed in a microfluidic device.

Original languageEnglish
Pages (from-to)4495-4500
Number of pages6
JournalAnalytical Chemistry
Issue number15
Publication statusPublished - Aug 1 2004

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry


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