JPS58119148A - Ion source of mass spectrograph - Google Patents

Abstract

PURPOSE:To cause an ion to promptly appear when reaching an ionization range without causing a time lag, by previously irradiating the second neutral particle beam to a sample before the ionization range. CONSTITUTION:A metallic rotating belt 6 is tensibly bridged on pulleys 7, 8 approximately arranged to a drawing out electrode 2 and a pulley 9 out of a vacuum, and outflowing fluid from a liquid chromatograph 10 is allowed to continuously adhere to the belt 6 in a sample attaching part 11, then a solvent is removed by a heater 12, thus the belt holding the residual sample component on its surface is transferred into an ionization chamber 1 through a difference pressure exhaust means 13. A fast neutral particle beam 19 is irradiated from a neutral particle source 18 in an ionizing part 17, and the sample component held on a surface of the belt 6 is ionized and guided to a mass spectrographing system through the electrode 2, focus electrode 3 and main slit 4. The an argon ion Ar<+> deflected by an applicable deflector 23 passes through the second collision chamber 24 introduced with argon gas and is mostly converted into an argon atom, and this argon atomic beam 25 is irradiated as the second neutral particle beam to the belt before the part 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ion source suitable for use when a sample solution separated by a liquid chromatograph is analyzed by a mass spectrometer.

Conventionally, a belt method is known as a method for introducing a sample solution separated by a liquid chromatograph into an ion source of a mass spectrometer. In this method, the liquid effluent from the liquid chromatograph is held open on a belt, the belt is introduced into an ion source, and the belt is heated at the ionization position to vaporize and ionize the sample. However, in this conventional method, the sample is evaporated by heating and then subjected to electron impact ionization or chemical ionization, so unstable samples are thermally decomposed during the evaporation stage, and non-volatile samples are not evaporated sufficiently. The number of samples that could be measured was extremely limited.

On the other hand, ionization methods that ionize samples by irradiating them with high-speed neutral particles have recently been attracting attention. This method has low ionization energy and soft ionization, high generation rate of negative ions as well as positive ions, and since it uses neutral particles, there is no charge-up and it is easy to use with insulating samples. It has many excellent features such as being able to be ionized. However, when this ionization method is combined with the belt method, the following problems arise. That is, in the above ionization method, there is a time lag between irradiation of neutral particles and the appearance of ions, and depending on the material, it may take 5 seconds or more. On the other hand, in the belt method, since the liquid effluent from the liquid chromatograph is spread on the belt, it is necessary to move the belt at a speed of approximately one order of magnitude before introducing it into the ion source. This causes the inconvenience that the neutral particle beam leaves the ionization region to which it is irradiated before the neutral particle beam is irradiated.

The present invention has been made in view of this point, and by irradiating the sample with the second neutral particle beam before the ionization region, ions can appear quickly without any time lag when the sample reaches the ionization region. It is characterized by the fact that it is possible to do so. The present invention will be explained in detail below using the drawings.

The drawing is a sectional view showing the configuration of an embodiment of the present invention, and 1 is an ionization chamber of a mass spectrometer. This ionization chamber contains an ion extraction electrode 2. Focus electrode 3. Main slit 4
is placed, and its interior is maintained at a high vacuum by a vacuum pump 5. 6 is an endless bendable metal rotary belt, and is arranged close to the extraction electrode 2.
8 and a boolean 99 outside the vacuum. Near the pulley 9, there is a sample attachment part 11 for continuously adhering the effluent from the liquid chromatograph 10 to the belt 6, and a sample attachment part 11 to the belt 6. A heater 12 is arranged to evaporate the solvent component from the adhering effluent, leaving only the sample component.The heater 12 removes the solvent and the belt holding the remaining sample component on the surface is evacuated by differential pressure. Means 13
is transferred into the ionization chamber 1 via the ionization chamber 1. This differential pressure exhaust means is the partition walls 14a, 14B).

having a chamber 151.15b formed by 14c;
Each room is equipped with an appropriate vacuum pump 1IISA depending on the degree of vacuum.

18b. The belt 6 is then transferred to the ionization chamber or into the atmosphere through passages provided in each partition wall, but the air circulation in this section is extremely small, so that the degree of vacuum in the ionization chamber is not deteriorated. Belt transfer can be performed.

The belt 6 transferred into the ionization chamber 1 in this way has an ionization section 17 set between the pulleys 1 and 8.
High-speed neutral particle beam 19 from a neutral particle source 18 to be described later
The sample components held on the surface of the belt 6 are ionized by the irradiation of the beam, and the sample components held on the surface of the belt 6 are ionized.
Focus electrode 3. It is guided through the main slit 4 to the mass spectrometry system.

The above-mentioned neutral particle source 1s is for creating a neutral particle beam given a high velocity, for example, an argon atomic beam. Argon gas is introduced, and argon gas is ionized and accelerated by electron impact to obtain an argon ion beam 20. An ion gun 21, a collision chamber 22 for colliding the argon ion beam 2e with floating argon gas lζ to deprive the argon ions of charge, and the charge mixed in the argon atomic beam emitted from the collision chamber 22 not being taken away. It is composed of a deflector 23 for rejecting argon ions Ar.

The argon ions Ar deflected by the deflector 23 pass through the second collision chamber 24 into which argon gas is introduced, and most of them are converted into argon atoms, and this argon atomic beam 25 becomes a second neutral A particle beam is irradiated onto the belt in front of the ion 1 section 1T.

In order to facilitate the irradiation of the argon atomic beam 19 and the extraction of ions, the belt surface between the pulleys 1 and 8 is inclined (for example, about 45 degrees) with respect to the extraction electrode 2. Location is taken into account. Further, 26 is a heater for evaporating and removing sample components remaining without being ionized.

In the above-described configuration, the belt is rotated in the direction of the arrow, and the belt is transferred at a constant speed through the differential pressure evacuation means 13, and the effluent from the liquid chromatograph 10 is placed on the sample attachment part 11, and the effluent from the liquid chromatograph 10 is transferred to the belt. The effluent is developed as a liquid chromatogram on Belut. The solvent component is removed from the developed effluent by the heater 12, and only the remaining sample components are held on the belt and transferred to the ionization section 1γ, where they are treated with argon atomic beams.
However, in the present invention, before reaching the ionization unit 11, the sample components undergo preliminary ionization by irradiation with the second argon atomic beam 25, and then the sample components are ionized immediately before ionization or before reaching the ionization unit 11. It has started to become ionized. Therefore, the sample components that reach the ionization section and are irradiated with the argon atomic beam 19 are immediately ionized, and no time lag occurs.

In addition, in the ionization section, the sample is ionized by colliding high-speed argon atoms (neutral particles) with the sample, so the vaporization process by heating, which is conventional, is not necessary, making it possible to eliminate thermal decomposition of the sample. It is.

Therefore, accurate measurements can be made even with unstable samples. Also, since the sample is ionized by colliding with high-speed argon atoms, even non-volatile substances or insulators can be efficiently ionized, expanding the range of samples that can be measured. .

In the embodiment described above, the argon ions separated by the deflector 23 are used to generate the second argon atomic beam 25.
Although the configuration is simplified by creating a source, it goes without saying that the configuration is not limited to this, and a second neutral particle source may be provided separately. Furthermore, by making the beam width of the second argon atomic beam 25 variable, the degree of preliminary ionization can be adjusted depending on the sample. For this purpose, variable lens means may be placed between the deflector 23 and the collision chamber 24.

Furthermore, although argon atoms were used as the neutral particles in the above-described embodiments, the present invention is not limited to this, and other atoms or neutral particles may be included.

[Brief explanation of drawings]

The drawing is a sectional view showing the configuration of an embodiment of the present invention. 1: Ionization chamber, 2: Ion extraction electrode, 5°163
．． 16b: Vacuum pump, 6=belt, 7,8°9: Pulley, 10: Liquid chromatograph, 11: Sample attachment part, 1
3: differential pressure exhaust means, 1T: ionization section, 18: neutral particle source, 19, 25: high continuous neutral particle beam, 22, 24: collision chamber, 23: deflector.

Claims (1)

[Claims] An evacuated ionization chamber, a belt that continuously transfers the sample to the ionization chamber from outside the vacuum, a differential pressure evacuation means provided at the introduction part of the belt to the ionization chamber, and a sample that is transferred to the belt outside the vacuum. means for depositing a solution; a neutral particle source for creating a neutral particle beam to be irradiated onto the belt in an ionization section in an ionization chamber; An ion source for a mass spectrometer, comprising an electrode for extracting and accelerating the particles, and configured to irradiate a second neutral particle beam onto the belt before reaching the ionization section.