Direct determination of zinc in steel samples by electrothermal vaporization inductively coupled plasma atomic emission spectrometry.
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Electrochemistry↗
Biomedical subjects
Satoshi Tsukahara
Publications and source records attributed to Satoshi Tsukahara.
Lactone cleavage reaction kinetics of rhodamine dye at liquid/liquid interfaces studied by micro-two-phase sheath flow/two-photon excitation fluorescence microscopy.
Two-photon excitation fluorescence microscopy was combined with the two-phase microflow system in order to measure the fast interfacial reaction rate at liquid/liquid interfaces. The lactone cleavage kinetics of octadecylrhodamine B (C(18)RB) at the toluene/water and heptane/water interfaces was studied by this new method. The organic solution containing the nonfluorescent lactone of C(18)RB was made to flow as an inner flow with an aqueous outer sheath flow. The diameter of the inner flow was <20 microm. A focused fundamental beam of a Ti:sapphire pulse laser of 780 nm was irradiated to the interface, and emitted fluorescence from the fluorescent product was detected by a charge-coupled device (CCD) camera or a streakscope. The increase in the concentration of the fluorescent form of C(18)RB was measured along the interface of the inner flow of the toluene/water and heptane/water systems for 80 micros just after the contact of two phases. The analysis made by the time-dependent Langmuir adsorption model with the aid of the digital simulation method gave the cleavage reaction rate constants of the lactone form of C(18)RB at the liquid/liquid interfaces.
Journal Article↗
Magnetic field enhanced microextraction rate of europium(III) with 2-thenoyltrifluoroacetone and oxalate at dodecane-water interface.
A microscopic system for the observation of reactions at a liquid-liquid interface was established, to which strong magnetic fields (0-0.4 T) could be applied with permanent magnets. In situ observation for the interfacial extraction of fluorescent and paramagnetic Eu(III) ion with 2-thenoyltrifluoroacetone (Htta) in dodecane was carried out. In the presence of oxalate (ox2-), micro-aggregates of Eu(III)-tta-ox complexes were generated in the aqueous phase before its extraction. When the micro-aggregates diffused to the dodecane-water interface, Eu(tta)3 was extracted with excess Htta in the dodecane phase. The microextraction process of the aggregates was observed as random flashes of Eu(tta)3 fluorescence at the dodecane-water interface. The single flash contained about 10(-16)-10(-14) mol of Eu(III). An application of magnetic fields made the flash frequency increase, which corresponded to an enhancement of interfacial Eu(III) extraction rate. The enhancement effect was attributable to the magnetophoresis of the paramagnetic microaggregates to the dodecane-water interface.
Journal Article↗
Migration analysis of micro-particles in liquids using microscopically designed external fields.
The recent development of new migration methods of micro-particles in liquids using various external fields is reviewed. The combination of a laser scattering force and a photothermal effect produced photothermal-conversion laser-photophoresis. A dielectric field generated in a planer or a capillary quadrupole electrode realized dielectrophoresis. Using a micrometer-scaled magnetic field gradient, the "Magnetophoretic velocimetry" of micro-particles was invented. Furthermore, the Lorentz force generated by combining an electric field and a magnetic field was utilized for electromagnetophoresis. These new methods were overlooked and the advantages in analytical use were discussed.
Journal Article↗
Effects of viability and lectin protein binding on dielectrophoretic behavior of single yeast cells.
The dielectrophoretic (DEP) behavior of individual yeast cells (5-7 microm in diameter) in aqueous media was observed in a fabricated planar quadrupole microelectrode with a working area of 100 microm in diameter by an optical microscope. The yeast cells migrated in the radial direction in the working area. The DEP velocity of the cells increased as they approached the electrode. The DEP trajectory of the cells was analyzed with a theoretical equation derived previously, and the dielectrophoretic mobility was determined. The dielectrophoretic mobility was found to be affected by the viability of cells, the conductivity of the medium, and the binding of lectin protein (concanavalin A) to the cell surface. These DEP behaviors were analyzed based on the permittivities and conductivities of the cell interior and wall, and those of the medium.
Concanavalin A↗