JPH06215729A - Mass spectrometer - Google Patents

Abstract

PURPOSE:To make the analysis of samples of different polarities without re-assembling an ion source by ionizing a sample of high polarity by an atmospheric pressure ion source from the rear part of an electron bombarding ion source for ionizing a sample of no polarity, and by guiding the sample ions. CONSTITUTION:A sample of no polarity flowed out of a gas chromatography 1 is ionized by electron bombarding ion sources 2-6, and is guided into an analysis part by a ripeller electrode 4. A sample of high polarity flowed out of a liquid chromatography 12 is ionized by atmospheric pressure chemical ionization ion sources 8-11 provided in the rear of the electron bombarding ion source, and by electrospray-ion sources 13-15. The trajectory of the sample ions emitted from each ion source is changed by a deflector electrode 7, and the sample ions are fed to a guiding analysis part from the rear part of the electron bombarding ion source in the direction of the ripeller electrode 4. Samples of no polarity to high polarity can thus be achieved without re-assembling the ion source.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to mass spectrometers, and more particularly to the analysis of sample ions ionized from a plurality of different ion sources.

[0002]

2. Description of the Related Art Conventional chromatograph mass spectrometers have been constructed by combining gas chromatographs or liquid chromatographs with mass spectrometers. However, the sample to be analyzed is a gas chromatograph with low polarity and liquid. The chromatograph is relatively medium to highly polar. Ionization methods for ionizing a sample from those polar planes have also used electron impact method for gas chromatographs, atmospheric pressure ionization method, frit-fab method, electrospray method for liquid chromatographs. It is necessary to change the source part, break the vacuum of the ion source housing and bring it to atmospheric pressure, then replace the ion source,
It was re-exhausting.

Even after recombining with various ion sources, it takes a long time to raise the temperature of the path from the chromatograph to the ion source and each ion source to a temperature for ionizing the sample with optimum ionization efficiency. And

[0004]

In the above-mentioned prior art, no consideration is given to the fact that the sample flowing out from the chromatograph has a wide range from non-polar to high-polarity. In addition to the bombarding ion source, several types of ion sources were required, and spectra were obtained by using them in combination. This method requires unnecessary time and labor because the ion source to be replaced is installed in a vacuum.

An object of the present invention is to install several kinds of ion sources in the ion source housing in advance in order to eliminate these drawbacks, and a low-polarity sample is higher in electron impact ion source than a gas chromatograph depending on the polarity of the sample. A polar sample is ionized by an ion source such as atmospheric pressure ionization, frit fab, or electrospray from a liquid chromatograph, and each ion is guided to the analysis section by a deflector electrode, so that various samples can be measured without changing the ion source. Especially.

[0006]

In order to achieve the above object, a relatively high-polarity sample flowing out from a liquid chromatograph is separated after an electron impact ion source for ionizing a non-polarity sample flowing out from a gas chromatograph. Ionization is carried out by the provided atmospheric pressure ion source (atmospheric pressure chemical ionization, electrospray), and the sample ions can be introduced. One mass spectrometer can simultaneously or simultaneously generate ions from several types of ion sources. It enables gas chromatograph mass spectrometry, liquid chromatograph mass spectrometry, and other measurements without changing the ion source for each sweep.

That is, a nonpolar sample is ionized by an electron impact ion source through a gas chromatograph as in a conventional product, and is converted into sample ions and introduced into an analysis section. On the other hand, a sample with polarity usually passes through a liquid chromatograph and is ionized by atmospheric pressure chemical ionization installed after the electron impact ion source, frit fab or electrospray ion source, and the direction of the sample ion is corrected by the deflector electrode. By doing so, the solvent molecules and the liquid chromatographic mobile phase that has not been ionized go straight and are exhausted. The sample ions enter after the electron bombardment ion source, are accelerated, are converged by the lens action, are sent to the analysis unit while being converged, and are recorded as sample ion spectra.

When used as a gas chromatograph mass spectrometer, the deflector voltage is changed to change the flight direction of ions from the liquid chromatograph so that sample ions cannot enter the electron impact ion source.
It functions as a conventional gas chromatograph mass spectrometer.

From the above, a plurality of ion sources are installed in one mass spectrometer so that samples having different polarities can be measured without changing the ion sources.

[0010]

The ionization of a non-polar sample such as gas chromatograph mass spectrometry uses an electron impact ion source which has been conventionally used. Polar substances are usually analyzed through a liquid chromatograph, and their ionization is performed by atmospheric pressure chemical ionization installed behind the electron impact ion source and ionization of the sample flowing out from the liquid chromatograph by an ion source such as electrospray. , The sample ions emitted from each ion source are changed in their trajectory by the deflector electrode, introduced into the repeller electrode direction after the electron impact ion source, and sent to the analysis unit, so various modes are possible without removing each ion source. Can be measured.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. A relatively nonpolar sample is injected from the gas chromatograph 1, and sample molecules that have flowed out after column separation are introduced into electron impact ion sources 2 to 6. In the electron impact ion source, the outflow component from the gas chromatograph is ionized by the collision of thermoelectrons generated by passing an electric current through the filament 3 and the sample molecule, and is extruded toward the analysis section by the repeller electrode 4, and then ionized in the ionization box 2. By the applied ion acceleration voltage, it is drawn out toward the earth slit 6, converges at the lens electrode 5 on the way, and enters the analysis section for analysis.

On the other hand, the sample from the liquid chromatograph 12 uses the electrospray 13 to 15 and the atmospheric pressure chemical ionization 8 to 11 depending on the mass number and polarity of the sample flowing out. That is, a substance having a high polarity and a high mass number is electrosprayed, and a substance having a low to medium polarity and a low to medium mass number is ionized by an atmospheric pressure chemical ionization ion source.

The electrospray sends the mobile phase from the liquid chromatograph through the capillary 15 and applies a voltage of about 3 to 5 kV to the counter electrode at the tip of the capillary. Very small droplets are generated from the tip of the capillary, and these droplets are charged with many positive or negative charges. The atomization is performed in the atmosphere, and while the droplet moves toward the counter electrode, the solvent is vaporized from the droplet surface and the droplet becomes smaller. The electric charge becomes localized on the surface of the droplet by electrolysis. When the droplet becomes smaller and the electric repulsive force exceeds the surface tension, the droplet is subdivided all at once, and finally the charge is transferred to the solute molecule (sample molecule), and the evaporation of ions directly from the liquid phase to the gas phase occurs. Once done, the sample molecules are ionized.

Atmospheric pressure chemical ionization ionizes solute molecules (sample molecules) with mobile phase solvent ions generated by ionizing a mobile phase solvent such as water or methanol, which is a mobile phase of a liquid chromatograph, by corona discharge under atmospheric pressure. Is to do. The sample flowing out from the liquid chromatograph is atomized together with the mobile phase in the atomizer 11, and most of the mobile phase solvent is exhausted in the desolvation chamber 10, and the remaining mobile phase solvent and the sample enter the needle electrode chamber, The mobile phase solvent is first ionized by the corona discharge generated from the needle electrode 16, and then the sample molecules are ionized by a kind of chemical ionization reaction by repeated ion molecule reactions. The ions generated here are the first
Pore 9, second pore 8 (electrospray is the first pore 1
4, through the second pore 13), the ion is corrected by the deflector electrode 7 for ion trajectory correction, enters the ion source from behind the electron impact ion source, is accelerated by the ion acceleration voltage applied to the ionization box, and enters the analysis section. Post-mass dispersion is observed as a spectrum. When the above method is adopted, the gas chromatograph / electron impact method, without desorption of the ion source,
Liquid chromatograph / electrospray, liquid chromatograph / atmospheric pressure chemical ionization method, etc. can be analyzed.

Also, by changing the voltage of the deflector electrode 7 for each mass insertion, the liquid chromatograph /
Alternate measurement of electrospray, liquid chromatograph / atmospheric pressure chemical ionization method is possible, and molecular ion is measured by electrospray, fragment ion is measured by atmospheric pressure chemical ionization method, and both data are combined to obtain one data. It becomes possible to add more information and make it a standard for data retrieval.

[0016]

According to the present invention, various ion sources are attached to one mass spectrometer, ions corresponding to the polarity of the sample are generated by these ion sources, and then the ion trajectory is changed by the deflector electrode. Then, it is introduced from behind the electron impact ion source and analyzed. The present invention enables analysis of non-polar to high-polarity samples without changing the ion source, and also enables simultaneous measurement of liquid chromatograph mass spectrometry and gas chromatograph mass spectrometry.

[Brief description of drawings]

FIG. 1 is a diagram showing a cross section and an ion source arrangement of an embodiment of the present invention.

[Explanation of symbols]

1 ... Gas chromatograph, 2 ... Ionization box, 3 ... Filament, 4 ... Repeller electrode, 5 ... Lens electrode, 6 ... Ground electrode, 7 ... Deflector electrode, 8, 13 ... 2nd pore,
9, 14 ... First pores, 10 ... Desolvation chamber, 11 ... Atomizer,
12 ... Liquid chromatograph, 15 ... Capillary, 16
... needle electrode, 17 ... deflector power supply, 18 ... electron beam, 19 ... sample ion beam.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Takahashi Toshiaki 832 Nagakubo, Horiguchi, Katsuta City, Ibaraki Prefecture 2 Within Nissan Measurement Engineering Co., Ltd. (72) Tomomi Bando 832 Nagakubo, Horiguchi, Katsuta, Ibaraki Prefecture (2) Inventor Toshihiro Shirasaki 832 Nagakubo, Horiguchi, Katsuta City, Ibaraki Prefecture

Claims (4)

[Claims] 1. A mass spectrometer having ion sources of different ionization systems, wherein ions ionized by atmospheric pressure ionization, electrospray, etc. are introduced from the direction opposite to the analysis unit of the electron impact ion source. Mass spectrometer characterized by pushing to. 2. The mass spectrometer according to claim 1, wherein the ions introduced into the electron impact ion source are introduced from respective ion sources such as an atmospheric pressure ion source through an ion direction changing electrode (deflector electrode). Total. 3. The ion from each ion source introduced into the analysis unit according to claim 2, wherein only the necessary ion, that is, the ion from the ion source to be studied is changed by changing the deflector voltage or the like. Is introduced into the analysis section. 4. The deflector voltage according to claim 3, wherein the deflector voltage is changed for each ion mode or for each mass insertion and extraction, and a single mass spectrometer simultaneously analyzes ions from a plurality of ion sources. Mass spectrometer.