Publications (11)16.83 Total impact
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Article: High-throughput walkthrough detection portal for counter terrorism: detection of triacetone triperoxide (TATP) vapor by atmospheric-pressure chemical ionization ion trap mass spectrometry.
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ABSTRACT: With the aim of improving security, a high-throughput portal system for detecting triacetone triperoxide (TATP) vapor emitted from passengers and luggage was developed. The portal system consists of a push-pull air sampler, an atmospheric-pressure chemical ionization (APCI) ion source, and an explosives detector based on mass spectrometry. To improve the sensitivity of the explosives detector, a novel linear ion trap mass spectrometer with wire electrodes (wire-LIT) is installed in the portal system. TATP signals were clearly obtained 2 s after the subject under detection passed through the portal system. Preliminary results on sensitivity and throughput show that the portal system is a useful tool for preventing the use of TATP-based improvised explosive devices by screening persons in places where many people are coming and going.Rapid Communications in Mass Spectrometry 09/2011; 25(17):2448-52. · 2.79 Impact Factor -
Article: On‐line combination of micellar electrokinetic chromatography and mass spectrometry using an electrospray–chemical ionization interface
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ABSTRACT: Micellar electrokinetic chromatography/mass spectrometry (MEKC/MS) using an electrospray–chemical ionization (ES-CI) source is described. The interface between micellar electrokinetic chromatography and mass spectrometry consists of an electrospray-type nebulizer and an atmospheric pressure chemical ionization source that uses a needle electrode. Aromatic amines (aniline, p-nitroaniline, and 1-naphthylamine) are analysed by MEKC/MS, using a phosphate buffer that includes 20 mM sodium dodecyl sulfate (SDS), and protonated molecular ions of the samples are clearly recorded on the ion electropherograms. The results show that the ES-CI technique is very promising as an MEKC/MS interface since MEKC/MS uses a high concentration of nonvolatile salts and surfactants.Rapid Communications in Mass Spectrometry 04/2005; 9(6):488 - 490. · 2.79 Impact Factor -
Article: Real-time-monitored decrease of trichlorophenol as a dioxin surrogate in flue gas using iron oxide catalyst.
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ABSTRACT: The decrease of trichlorophenol by injecting oxidation catalyst into a municipal solid waste incinerator was monitored in real time. Direct sampling atmospheric pressure chemical ionization (APCI)/ion trap mass spectrometry (ITMS) was used for the real-time monitoring. The oxidation catalyst was iron oxide type, which exponentially reduced trichlorophenol emission. CO emission, however, did not show any correlation with the catalyst injection rate. Simultaneous analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs) suggested that real-time monitoring of trichlorophenol as a surrogate of PCDDs/PCDFs, has a potential to timely control the optimum injection rate of PCDD/PCDF suppression catalyst continuously and economically.Chemosphere 04/2004; 54(10):1475-80. · 3.21 Impact Factor -
Article: Detection of Military Explosives by Atmospheric Pressure Chemical Ionization Mass Spectrometry with Counter‐Flow Introduction
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ABSTRACT: To detect vapors from explosives, we have developed a new detection system based on a novel ion source for atmospheric pressure chemical ionization (APCI). The direction of the sample gas flow introduced into the ion source is opposite to that of the ion flow produced by the ion source. We call this technique “counter-flow introduction” (CFI). The CFI ion source has high ionization efficiency for nitro-compounds and is installed in an ion-trap mass spectrometer. Our tests on various military explosives show that this system is suitable for practical on-line explosive detection; namely major explosives can be detected within a few seconds without any pretreatment of the sample gases.Propellants Explosives Pyrotechnics 09/2002; 27(4):224 - 228. · 1.10 Impact Factor -
Article: Atmospheric Pressure Chemical Ionization Interface for Capillary Electrophoresis/Mass Spectrometry
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Article: Sonic Spray Ionization Method for Atmospheric Pressure Ionization Mass Spectrometry
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Article: Direct Coupling of Semi‐micro Liquid Chromatography and Sonic Spray Ionization Mass Spectrometry for Pesticide Analysis
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ABSTRACT: Direct coupling of semi-micro liquid chromatography and sonic spray ionization mass spectrometry is demonstrated and shown to be a very powerful technique for pesticide analysis. Direct coupling is achieved by using a high flow rate of nitrogen gas in sonic spray ionization and a high operating temperature in the sampling orifice of the atmospheric ionization mass spectrometer. The detection limit for simazine is about 300 fmol based on quantitative analysis in the range between 1 pmol and 1 nmol. A mixture of three pesticides was successfully analyzed using semi-micro liquid chromatography/mass spectrometry.Rapid Communications in Mass Spectrometry 05/1999; 10(15):1891 - 1893. · 2.79 Impact Factor -
Article: Multiply‐charged Ion Formation by Sonic Spray
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ABSTRACT: In sonic spray ionization technique, a solution from a fused-silica capillary is sprayed with a sonic gas flow coaxial to the capillary. The current for the ions produced and for the charged droplets is found to be dramatically enhanced when a voltage is applied to a surrounding metal piece, which is isolated from the solution by the fused-silica capillary. This can be ascribed to the induced concentration difference between positive and negative ions in the solution near the surface. Furthermore, multiply-protonated molecules produced in this way from protein solutions are analyzed with a quadrupole mass spectrometer. The ion intensity shows a strong dependence on the voltage but the diameter of the droplet produced by the spray is likely to be independent of the voltage. Thus, we conclude that the charge density of the droplet is regulated by the voltage.Rapid Communications in Mass Spectrometry 12/1998; 10(13):1703 - 1705. · 2.79 Impact Factor -
Article: Electrostatic ion guide using double cylindrical electrode for atmospheric pressure ionization mass spectrometry
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ABSTRACT: A novel electrostatic ion focusing lens that consists of two cylindrical electrodes positioned coaxially with each other is described. Square openings are formed in the inner electrode and their angular positions alternate by 90° with respect to the neighboring openings in the axial direction. When a potential difference is applied between the inner and outer electrodes, an electric field penetrates into the interior of the inner electrode through the openings. In the capillary electrophoresis/mass spectrometry analysis of peptides, use of the lens makes it possible to apply a higher voltage to the postacceleration dynode and the signal to background ratio is improved by a factor of 7. © 1996 American Institute of Physics.Review of Scientific Instruments 07/1996; · 1.37 Impact Factor -
Article: Micellar electrokinetic chromatography—mass spectrometry using a high-molecular-mass surfactant on-line coupling with an electrospray ionization interface
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ABSTRACT: On-line coupling between micellar electrokinetic chromatography (MEKC) and mass spectrometry (MS) was studied with a high-molecular-mass surfactant and an electrospray ionization interface (ESI). A high-molecular-mass surfactant, butyl acrylate-butyl methacrylate-methacrylic acid copolymer sodium salt (BBMA), was employed as a pseudo-stationary phase for an on-line MEKC-MS system. BBMA and a minor component separated by size-exclusion chromatography were determined by ESI-MS. No major ion from the BBMA polymer was detected. The BBMA micelle functioned successfully as the pseudo-stationary phase in a 10 mM ammonium formate buffer containing 10% methanol. Five standard compounds, phenyltrimethylammonium chloride, 1-naphthylamine, quinine sulfate, tetraphenylphosphonium chloride and octaoxyethylenedodecanol, were separated by MEKC and detected by MS. The effects of the concentrations of BBMA on the separation and sensitivity in MEKC-MS were studied. MEKC-MS with BBMA was applied to the separation and detection of a standard mixture of sulfamides.Journal of Chromatography A. -
Article: Recent progress in atmospheric pressure ionization mass spectrometry
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ABSTRACT: Atmospheric pressure ionization (API) is used as an interface in liquid chromatography-mass spectrometry and capillary electrophoresis-mass spectrometry. In API, quasi-molecular ions of biological molecules in solution are produced at atmospheric pressure. There have recently been several significant advances in spray ionization techniques, which use a solution spraying process. This article gives an overview of three spray ionization techniques: electrospray, ion spray, and sonic spray. It presents their characteristic features and describes the ion formation processes from charged droplets. Furthermore, the charged droplet formation process for each technique is described in terms of the non-uniformity in positive and negative ions in solution as well as in terms of the atomization process.TrAC Trends in Analytical Chemistry.
Top co-authors
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Institutions
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2002–2011
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Hitachi, Ltd.
- Central Research Laboratory
Tokyo, Tokyo-to, Japan
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