Anelva Corporation

Tohru Sasaki

Yoshiro Shiokawa

Megumi Nakamura

Toshihiro Fujii

An apparatus for ion attachment mass spectrometry provided with an ion emitter for emitting positively charged metal ions, an ionization chamber for causing attachment of the metal ions to a gas to be detected, a third component gas introduction mechanism for introducing a third component gas into the ionization chamber, and a mass spectrometer for mass separation and detection of the detected gas with the metal ions attached. The third component gas introduction mechanism is provided with three types of third component gases and selectively introduces one type of third component gas from the three types of third component gases. Due to this, the occurrence of interference peaks due to macromers of third component gases with each other, macromers of third component gases and high concentration ingredients, etc. is prevented and accurate mass analysis made possible.

Method and apparatus for ion attachment mass spectrometry

An ionization apparatus according to the present invention has a mechanism for causing metal ions emitted from an ion emitter to attach to an introduced target gas so as to generate ions of the sample gas and emits the ions of the sample gas to a mass spectrometer. The mass spectrometer has a zone in which one or both of an electric field and magnetic field are formed. As the electrode for causing the generation of cleaning plasma in the ionization zone generating the ions of the sample gas, the ion emitter is used. The ion emitter causes the generation of plasma in connection with a hollow vessel and removes deposits on components facing the ionization zone by the plasma. The plasma cleaning process is performed consecutively at a suitable timing after the ionization process. Due to the above configuration, deteriorated performance in ionization can be restored in a short time, a memory effect can be prevented, and accurate mass spectrometry becomes possible. The ionization apparatus of the present invention is suitable for a mass spectrometry apparatus.

Ionization apparatus

An apparatus for ion attachment mass spectrometry provided with a reaction chamber for causing positively charged metal ions to attach to a gas to be detected; a mass spectrometer for mass separation and detection of the detection gas; an analysis chamber in which the mass spectrometer is placed; differential evacuation chambers for connecting the reaction chamber and analysis chamber; a data processor for receiving and processing the mass signal from the mass spectrometer; and vacuum gauges for measuring the total pressure of the reduced pressure atmosphere of the reduced pressure atmosphere reaction chamber, a differential evacuation chamber, and an analysis chamber. The total pressure signal from the vacuum gauge measured during the measurement is input to one of the data processor, introduction mechanism, and evacuation mechanism. The data processor has a processing means for performing quantitative analysis of each component utilizing the fact that sensitivity of each component has dependency on the total pressure of the reduced pressure atmosphere and that the dependency on total pressure differs for each component.

Metal ions are attached to a sample gas in an ionization chamber to produce ions of the sample gas. The ions of the sample gas pass through a mass spectrometer formed by an electromagnetic field for separation by mass. The mass separated ions of the sample gas are detected and measured by a detector as an ion current. Further, a metal ion emitter for emitting metal ions is arranged at the upstream side of a region controlled to a reduced pressure atmosphere where the flow of gas becomes viscous, a sample gas inflow part for introducing the sample gas to the downstream side where the metal ions are transported, and the sample gas ionized by attachment of the metal ions passes through the opening of the aperture plate and transported to the mass spectrometer. A second gas inflow part is arranged at the upstream side of the metal ion producing region. A second gas supplied by the second inflow part flows through the metal ion producing region and sample gas ionization region. Due to this configuration, it is possible to suppress contact of the sample gas with the metal ion emitter, prevent contamination of the metal ion emitter, and perform mass spectrometry stably over a long term.

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Fuchu, Japan

Tohru Sasaki