研究者詳細 - 金田　隆

論文 - 金田　隆

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Determination of inorganic anions in human saliva by zwitterionic micellar capillary electrophoresis 査読

M Mori, WZ Hu, JS Fritz, H Tsue, T Kaneta, S Tanaka

FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY 370 ( 4 ) 429 - 433 2001年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER-VERLAG

Capillary electrophoresis (CE) using sulfobetaine-type zwitterionic micelles as the background electrolyte (BGE) has been used to determine inorganic anions in human saliva. The zwitterionic micelles resulted in unique migration behavior for the separation of inorganic anions. They also prevented adsorption of proteins on the inner wall of the capillary. These properties of the zwitterionic micelles enabled the direct determination of inorganic anions in human saliva. Three species of inorganic anions, NO2-, NO3-, and SCN-, were found in real samples and the analysis was achieved within 3 min. Direct UV-absorption was used as the detection method and the detection limits for these anions were 2.0, 1.0, and 5.0 mu mol L-1, respectively (0.09, 0.06, and 0.30 mug mL(-1)).

DOI： 10.1007/s002160100804

Determination of motility forces of bovine sperm cells using an "optical funnel" 査読

T Kaneta, N Mishima, T Imasaka

ANALYTICAL CHEMISTRY 72 ( 11 ) 2414 - 2417 2000年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

An optical funnel, a new technique for the evaluation of the force of a microorganism, was applied to the determination of the motility force of bovine sperm cells. In this approach, sperm cells, suspended in an aqueous solution, are introduced into a now cell, to which radiation pressure is applied from the direction opposite to a medium flow. The sperm cell, which is moving in a stream, is captured by radiation pressure and forced to move to the position at which the force induced by the laser radiation is equal to the force induced by a medium now. The sperm cell then escapes by its own power on the way to this equilibrium (entrapping) position. The radiation force increases with decreasing distance from the focal point, and as a result, the force of the sperm cell can be determined by measuring the position where the sperm cell escaped against the laser irradiation field. The motility farce of the sperm cell was measured in aqueous solution at different pH values and potassium ion concentrations, It was possible to measure more than 250 sperm cells in 3 h, Thus, the optical funnel has potential for use as a rapid and repetitive means for the determination of the motility force of the sperm cell.

DOI： 10.1021/ac991458q

Visualization of an immunological reaction between single antigen and antibody molecules by optical chromatography 査読

S Miki, T Kaneta, T Imasaka

ANALYTICA CHIMICA ACTA 404 ( 1 ) 1 - 6 2000年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Optical chromatography, which is a technique for the separation of microscopic particles using a radiation force, is applied to kinetic studies of an immunoreaction. Polystyrene beads coated with antibodies react with antigens to produce conjugated beads, which comprise two beads and some antigens. The resulting conjugated beads are separated from the single beads. The detection limit of the antigen is <1 ng ml(-1), which is smaller than that reported in a previous paper [T. Hatano, T Kaneta, T. Imasaka, Anal. Chem. 69 (1997) 2711], and can be achieved using 2 mu m-diameter beads. The sensitivity in the present method can be further enhanced by increasing the particle size. In addition, the dissociation reaction of the conjugated beads is evaluated by using an on-column reaction technique, which allows the direct monitoring of the formation and dissociation of the conjugated beads. The rate constant for the dissociation of the conjugated beads is determined to be 4.0 x 10(-3) s(-1) for the case of conjugated beads combined by a single bond. (C)2000 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0003-2670(99)00669-8

Hadamard transform capillary electrophoresis 査読

T Kaneta, Y Yamaguchi, T Imasaka

ANALYTICAL CHEMISTRY 71 ( 23 ) 5444 - 5446 1999年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

This paper reports the first demonstration of a multiplex sample injection technique in capillary electrophoresis, The sample was injected into a capillary (effective length, 4 cm) as a pseudorandam Hadamard sequence by a photodegradation technique using a high-power gating laser, and the fluorescence signal, which was measured using a probe excitation beam, was decoded by an inverse Hadamard transformation. The signal-to-noise ratio was improved by a factor of 8, which was in good agreement with the theoretically predicted value of 8.02. This approach is potentially useful for the enhancement of the sensitivity by 3 orders of magnitude in high-resolution capillary electrophoresis, combined with fluorescence detection.

DOI： 10.1021/ac990625j

Diffractive optical chemical sensor based on light absorption 査読

F Nakajima, Y Hirakawa, T Kaneta, T Imasaka

ANALYTICAL CHEMISTRY 71 ( 13 ) 2262 - 2265 1999年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

A new type of chemical sensor based on light absorption is proposed. An array of zones alternatively containing the pH indicator thymolphthalein is formed in a gelatin film. By changing the sample solution from acidic to alkaline, a blue stripe appears in the gelatin film. This acts as a transmission grating and diffracts the introduced laser beam. Theory predicts that this method, which is based on light absorption/beam diffraction, is as sensitive as or more sensitive than fluorometry.

DOI： 10.1021/ac990216n

Optical chromatography: Size determination by eluting particles 査読

J Makihara, T Kaneta, T Imasaka

TALANTA 48 ( 3 ) 551 - 557 1999年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

A new method for the determination of particle size was developed using optical chromatography. After separating polystyrene particles, the laser power was gradually reduced, permitting the elution of small to large particles. Particle size was calculated from the laser power when the particle was eluted with a medium flow. This approach is more accurate than the technique previously reported because there is no need to determine the position of the beam waist. Advantages of the new approach are discussed theoretically and experimentally. The precision in size determination was improved by a factor of 3.3, i.e. the standard deviation in the measurement was reduced from 10 to 3% for 1 mu m beads by replacing optical chromatography with the present method. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0039-9140(98)00272-0

Indirect detection of amino-substituted polycyclic aromatic hydrocarbons in cyclodextrin-modified micellar electrokinetic chromatography combined with diode laser-induced fluorometry 査読

T Kaneta, Y Saito, T Imasaka

JOURNAL OF CHROMATOGRAPHY A 831 ( 2 ) 285 - 292 1999年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Indirect fluorescence detection in cyclodextrin (CD)-modified micellar electrokinetic chromatography (MEKC) was demonstrated by using a diode laser as an excitation source. Amino-substituted polycyclic aromatic hydrocarbons (PAHs), which have no absorption band in the deep-red region, were used as model compounds since it was difficult to separate them by conventional MEKC. In the preliminary study, the separation of amino-substituted PAHs was achieved using gamma-CD as a modifier. The fluorescence intensity of the visualizing reagent, oxazine 750, increased in the presence of gamma-CD due to the complex formation of oxazine 750 with gamma-CD. Consequently, the peak areas of amino-substituted PAHs were observed to decrease with increasing concentration of gamma-CD. Detection limits were improved due to the enhancement in efficiency and dynamic reserve by adding small amounts of gamma-CD. The results obtained in this study were in good agreement with the proposed model. (C) 1999 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0021-9673(98)00925-X

Separation and detection of cyanine-labeled amino acids by micellar electrokinetic chromatography combined with fluorescence detection using diode-based solid-state lasers 査読

T Kaneta, T Komatsubara, H Shiba, T Imasaka

ANALYTICAL SCIENCES 14 ( 5 ) 1017 - 1019 1998年10月

The "Optical Funnel". A technique for measuring a microorganism's power 査読

N Mishima, T Kaneta, T Imasaka

ANALYTICAL CHEMISTRY 70 ( 16 ) 3513 - 3515 1998年8月

記述言語：英語出版者・発行元：AMER CHEMICAL SOC

A novel and potentially useful optical technique called an "optical funnel" has been developed, The technique utilizes a system in which a microorganism is suspended by equilibrium between the medium now and the radiation pressure applied in the opposite direction. At equilibrium, i.e., when the force of the laser pressure Is equal to the force of the moving stream, the microorganism is captured. At this point, it has the ability to escape on its own power, Since the force applied to the microorganism is calculated on the basis of a ray-optics model, it is possible to measure the magnitude of the microorganism's power. A Trachelomonas volvocina cell was determined to have a power of similar to 1 pN, This technique is superior to the laser trapping technique, which is currently used in these determinations, since it is possible to capture numerous organisms in a single experiment, thus allowing the calculation of the average power for an organism with minimal effort, in terms of repetitive samplings and measurements.

DOI： 10.1021/ac980199m

Miniaturized injection method using silver-coated capillaries in DNA sequencing by multiplexed capillary electrophoresis 査読

T Kaneta, H Jeong, ES Yeung

HRC-JOURNAL OF HIGH RESOLUTION CHROMATOGRAPHY 21 ( 5 ) 287 - 290 1998年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

Silver-coated capillaries were used for direct sample injection in multiplexed capillary electrophoresis. The absence of an additional electrode simplifies mechanical alignment, reduces contamination, and decreases the amount of sample needed. Capillaries were coated by a silver paint which is a suspension of silver particles in an organic solvent. To provide electrical contact, the upper part of the capillary and a platinum wire were wound together by a copper wire. Electrical resistance from the platinum wire to the tip of the capillary was small enough (7 Omega to 50 Omega) to inject large amounts of DNA samples. Electrokinetic injection from eight separate sample vials to eight capillaries was demonstrated for DNA sequencing by multiplexed capillary electrophoresis. Signal-to-noise ratio and resolution were good enough to call up to 350 base pairs.

DOI： 10.1002/(SICI)1521-4168(19980501)21:5<287::AID-JHRC287>3.0.CO;2-#

Determination of cyanine-labeled amino acid enantiomers by cyclodextrin-modified capillary gel electrophoresis combined with diode laser fluorescence detection 査読

T Kaneta, H Shiba, T Imasaka

JOURNAL OF CHROMATOGRAPHY A 805 ( 1-2 ) 295 - 300 1998年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Enantiomeric amino acids were labeled with a cyanine derivative (Cy5) for selective determination by capillary electrophoresis combined with diode laser-induced fluorometry. Cyanine-labeled glutamic acid has a high negative charge so that it was difficult to detect by conventional capillary zone electrophoresis due to its electrophoretic mobility being greater than the electroosmotic mobility. Thus, cyclodextrin-modified capillary gel electrophoresis using replaceable poly(vinylpyrrolidone) (PVP), which effectively suppresses the electroosmotic flow, was employed to separate Cy5-labeled amino acid enantiomers. The separation of six amino acid enantiomers could be achieved by using 1% PVP solution containing 70 mM gamma-cyclodextrin. It was also shown that PVP does not affect the selectivity of optical isomers. (C) 1998 Elsevier Science B.V.

DOI： 10.1016/S0021-9673(98)00023-5

Application of optical chromatography to immunoassay 査読

T Hatano, T Kaneta, T Imasaka

ANALYTICAL CHEMISTRY 69 ( 14 ) 2711 - 2715 1997年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

Optical chromatography, a new separation technique involving the use of a radiation force and a medium flow, is used for trace analysis of protein. Two polystyrene beads, coated with antibody (anti-mouse IgG), are combined in the presence of an antigen (mouse IgG). The bound (B) and free (F) beads are readily separated by optical chromatography, and the B/F ratio can be correlated with the concentration of antigen (protein). Nanomolar concentrations of protein can be measured by this technique. The rates of the forward and reverse immunological reactions were independently determined by measuring the time of formation and dissociation, respectively, of the immunobeads.

DOI： 10.1021/ac970081q

Theory of optical chromatography 査読

T Kaneta, Y Ishidzu, N Mishima, T Imasaka

ANALYTICAL CHEMISTRY 69 ( 14 ) 2701 - 2710 1997年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

To evaluate the performance of optical chromatography, a number of equations are theoretically derived using a ray-optics model. These mathematical formalisms are experimentally verified by determining the relationship between the velocity of motion of a polystyrene bead with respect to the intensity of an applied radiation force under the condition where there exists no applied fluid now. The force is confirmed to be at a maximum at the focal point and to decrease with increasing distance from this position. The radiation force is verified to be proportional to the square of the particle size when the particle diameter is much smaller than the beam diameter. In addition, the radiation force is ascertained to be proportional to the laser power. These results are in excellent agreement with the proposed theoretical model, which is based on ray optics. Furthermore, by analogy with conventional chromatography, fundamental parameters such as retention distance, selectivity, theoretical plate number, and resolution are calculated, and optimum conditions for chromatographic separation are discussed. Based on the results obtained, the dynamic range can be extended by increasing laser power and decreasing now rate. Peak broadening is primarily caused by variations in laser power and now rate of the medium for large particles (> 1 mu m). It is possible, in theory, to distinguish particles whose diameters differ by less than 1% for particles with a diameter larger than 1 mu m. Three sizes of polystyrene beads are well separated at a now rate of 20 mu m s(-1) and a laser power of 700 mW. This technique is also applied to the separation of human erythrocytes. Two fractions, one consisting of cells ranging from 1.5 to 2.4 mu m in diameter and another consisting of cells ranging from 3.5 to 5.7 mu m in diameter, are observed. Optical chromatography is useful for separation and size measurement of particles and biological cells.

DOI： 10.1021/ac970079z

Detection of a specific DNA fragment by free-solution capillary electrophoresis using a fluorescent DNA probe measured by semiconductor laser-induced fluorometry 査読

T Kaneta, T Okamoto, T Imasaka

ANALYTICAL SCIENCES 12 ( 6 ) 875 - 880 1996年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：JAPAN SOC ANALYTICAL CHEM

Semiconductor laser-induced fluorescence detection of native (target) DNA has been accomplished by free-solution capillary electrophoresis (CE) using an oligonucleotide labeled with a cyanine dye as a DNA probe. A mixture of probe DNA and target DNA, which is complementary to probe DNA, is incubated to form hybrid DNA; the mixture is then injected into a capillary. Single-stranded probe DNA and double-stranded hybrid DNA were separated by free-solution CE. A 19mer oligonucleotide labeled with fluorescein isothiocyanate (FITC) was used as probe DNA in a preliminary study. The stability of double-stranded DNA during migration was evaluated by changing the temperature of the solution in the capillary, i.e. the applied voltage in CE. The dissociation of double-stranded DNA was appreciable at high applied voltages. Thus, suppressing the temperature in the capillary, i.e. optimization of the voltage, was required in order to prevent the dissociation of double-stranded DNA. Furthermore, a new labeling reagent, a cyanine derivative, was synthesized in order to be applied to semiconductor laser-induced fluorometry. The detection limit was 8 x 10(-9) M for probe DNA.

DOI： 10.2116/analsci.12.875

Migration behavior of niacin derivatives in capillary electrophoresis 査読

S Tanaka, K Kodama, T Kaneta, H Nakamura

JOURNAL OF CHROMATOGRAPHY A 718 ( 1 ) 233 - 237 1995年12月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE BV

The migration behaviour of niacin derivatives was investigated by capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC). When the pH of the buffer solution is lower than the pK(a) of the pyridine ring in the niacin derivatives, they are positively charged by protonation on the pyridine ring and migrate electrophoretically. The mobilities of niacin derivatives in CZE were controlled by the pH of the migrating buffer. Good separation of thirteen niacin derivatives was achieved at pH 2.8. Further, to shorten the analytical time and to achieve a more complete separation, an investigation by MEKC using sodium dodecyl sulfate micelles was performed. All thirteen niacin derivatives were eluted within 30 min and a satisfactory separation was achieved.

DOI： 10.1016/0021-9673(95)00634-6

OPTICAL CHROMATOGRAPHY 査読

T IMASAKA, Y KAWABATA, T KANETA, Y ISHIDZU

ANALYTICAL CHEMISTRY 67 ( 11 ) 1763 - 1765 1995年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

A new and potentially useful method for separation of particles by optical radiation pressure is described and demonstrated in this study, A laser beam is focused into the solution, which contains particles counterflowing coaxially in a capillary, The particle is focused into the center line of the laser beam by radiation pressure, The particle is turned around, accelerated, passed through a beam waist, decelerated by a liquid now, and drifts, at which point the radiation pressure is identical to the force induced by the liquid now, resulting in separation of particles as a function of size.

DOI： 10.1021/ac00107a003

INDIRECT DETECTION OF AROMATIC-HYDROCARBONS BY SEMICONDUCTOR-LASER FLUOROMETRY IN MICELLAR ELECTROKINETIC CHROMATOGRAPHY 査読

T KANETA, T IMASAKA

ANALYTICAL CHEMISTRY 67 ( 5 ) 829 - 834 1995年3月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AMER CHEMICAL SOC

A semiconductor laser is used as an exciting light source in indirect fluorescence detection of neutral samples separated by micellar electrokinetic chromatography. A surfactant, tetradecyltrimethylammonium chloride, is used to form micelles, which act as a pseudostationary phase in the chromatographic separation. This surfactant has a positive charge, thus preventing adsorption of a visualizing agent, oxazine 750 (which contains a positive charge), to the capillary wall (which is negatively charged). The detection mechanism is based on the exclusion of the fluorophore, which is located in the hydrophilic part of the micelle, by a hydrophilic sample. The fluorescence intensity is reduced when the fluorophore is released into the aqueous solution. Separations of several aromatic compounds are demonstrated, and the parameters affecting the selectivity are discussed.

DOI： 10.1021/ac00101a007

SEPARATION OF POLYCYCLIC AROMATIC-HYDROCARBONS BY MICELLAR ELECTROKINETIC CHROMATOGRAPHY WITH LASER FLUORESCENCE DETECTION 査読

T KANETA, T YAMASHITA, T IMASAKA

ANALYTICA CHIMICA ACTA 299 ( 3 ) 371 - 375 1995年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE BV

Polycyclic aromatic hydrocarbons (PAHs) were separated by micellar electrokinetic chromatography and were detected by laser fluorometry. The PAHs with large molecular weights were separated by using dimethylformamide as an organic modifier. A He-Cd laser (325 nm, 5 mW) or a blue semiconductor laser (415 nm, 50 mu W) was used as an exciting light source. The detection limit (S/N = 3) for perylene was 1.4 X 10(-7) M under He-Cd laser excitation or 3.4 x 10(-7) M under semiconductor laser excitation.

DOI： 10.1016/0003-2670(94)00317-F

Indirect detection by semiconductor laser-induced fluorometry in micellar electrokinetic chromatography 査読

T KANETA, T IMASAKA

ADVANCES IN FLUORESCENCE SENSING TECHNOLOGY II 2388 67 - 70 1995年

EFFECT OF ORGANIC MODIFIER ON RESOLUTION OF HYDROPHOBIC COMPOUNDS BY MICELLAR ELECTROKINETIC CHROMATOGRAPHY 査読

T KANETA, T YAMASHITA, T IMASAKA

ELECTROPHORESIS 15 ( 10 ) 1276 - 1279 1994年10月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：VCH PUBLISHERS INC

Three organic modifiers, methanol, acetonitrile, and dimethylformamide, were used as organic modifiers to improve the resolution of hydrophobic compounds in micellar electrokinetic chromatography. The capacity factor decreased with increasing concentration of organic modifier. Acetonitrile and dimethylformamide were more effective modifiers to decrease the capacity factor than methanol. Maximum resolution was obtained when the capacity factor was reduced to about 2. Methanol enhanced the resolution for less hydrophobic compounds, while acetonitrile and dimethylformamide were better modifiers to improve the resolution for strongly hydrophobic compounds.

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