We developed a micro total analysis system (mu-TAS) incorporating chemiluminescence detection, in which the chemiluminescence reaction of isoluminol isothiocyanato (ILITC) (as a chemiluminescence reagent for labeling)-microperoxidase (as a catalyst)-hydrogen peroxide (as an oxidant) was adopted. The analysis system performed the following three processes on a microchip: immune reaction for high selectivity, electrophoresis for formation and transportation of the sample plug, and chemiluminescence detection for high sensitivity. The three processes were compactly integrated onto the microchip to give the mu-TAS. The microchip contained two microchannels that crossed at an intersection, while the ends of the microchannels accessed four reservoirs. As the first process, the immune reaction was performed using an antibody-immobilized glass bead. The glass bead was placed in one of the reservoirs along with antigen (analyte) and a known amount of ILITC-labeled antigen to set up a competitive immune reaction. For electrophoresis, as the second process, the reactant after the immune reaction was fed electrophoretically into the intersection resulting in a sample plug. The sample plug was then moved into another reservoir containing hydrogen peroxide solution. At this point, chemiluminescence detection was performed as the third process: the labeled antigen mixed with the hydrogen peroxide and the catalyst included in the migration buffer to produce chemiluminescence. Chemiluminescence was detected by a photomultiplier tube located under the reservoir. The mu-TAS described here was capable of determining, with high selectivity and sensitivity, human serum albumin or immunosuppressive acidic protein as a cancer marker in human serum.

We developed a capillary chromatography system by using an open capillary tube made of fused-silica, polyethylene, or polytetrafluoroethylene, and a water-hydrophilic/hydrophobic organic mixture carrier solution, called tube radial distribution chromatography (TRDC) system. By comparing with chromatograms obtained via the TRDC system, fluorescence photographs and profiles of the fluorescent dyes dissolved in the carrier solvents in capillary tubes were observed under laminar flow conditions. The chromatograms were obtained for a model mixture analyte consisting of 1-naphthol and 2,6-naphthalenedisulfonic acid with the TRDC system, by using a fused-silica capillary tube and a water-acetonitrile-ethyl acetate carrier solution. By altering the carrier flow rates, we examined the fluorescence photographs and profiles of the dyes, perylene and Eosin Y, dissolved in the carrier solvents in the capillary tube by using a fluorescence microscope equipped with a CCD camera. As confirmed by fluorescence observations, the major inner and minor outer phases generated in the capillary tube were based on the tube's radial distribution of the carrier solvents. We designed and manufactured a microreactor incorporating microchannels in which three narrow channels combined to form one wide channel. When the carrier solvents containing the dyes were fed into the channels, the inner and outer phase generations were also observed in the narrow and wide channels, strongly supporting the conclusions concerning the tube radial distribution phenomenon of the solvents.

When ternary mixed solutions of water-hydrophilic/hydrophobic organic solvents are fed into a microspace under laminar flow conditions, the solvent molecules are radially distributed in the microspace. The specific fluidic behavior of the solvents is termed "tube radial distribution phenomenon" (TRDP). In this study, water-acetonitrile-ethyl acetate mixed solutions (3:8:4 volume ratio) containing fluorescent dyes, perylene (0.1 mM) and Eosin Y (1 mM), were fed into fused-silica capillary tubes (75 μm i.d.) for investigating the TRDP with a fluorescence microscope-CCD camera under various analytical conditions. The pressure at the observation point for the fluorescence on the tube was changed by altering the flow rates, capillary total lengths, and capillary effective lengths. The obtained fluorescence images showed that the TRDP in the capillary tube created the inner and outer phases, i.e., the organic solvent-rich major inner and the water-rich minor outer phases in this case, providing the kinetic liquid-liquid interface. The formation of the inner and outer phases in the capillary tube was observed at flow rates of 0.5 -2.0 μL min -1 under the present analytical conditions. We also discuss the specific formation locations of the major and minor solvents.

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