JPS592144B2 - Mass spectrometer ion source - Google Patents

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 a liquid chromatograph is developed and held on a belt, this belt is introduced into an ion source, and the belt is heated at the ionization position to evaporate 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 sufficiently evaporated. Without,
The samples that could be measured were extremely limited.
The present invention was made in view of this point, and eliminates the above-mentioned drawbacks by colliding neutral particles (atoms) given a high velocity to the sample on the belt to ionize it without heating. It is characterized by

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 51 is an ionization chamber of a mass spectrometer. An ion extraction electrode 2, a focus electrode 3, and a main slit 4 are placed in this ionization chamber, and the inside thereof is maintained at a high vacuum by a vacuum pump 5. 6
is made into an endless bendable rotary belt, and is stretched around pulleys 7 and 8 placed close to the extraction electrode O2 and a pulley 9 outside the vacuum.

In the vicinity of the pulley 9, there is a sample attachment part for continuously adhering the effluent from the liquid chromatograph 10 to the belt 6, and a sample attachment part for continuously adhering the effluent from the liquid chromatograph 10 to the belt 6.
A heater 12 is provided to evaporate the solvent components while leaving a residue behind. The belt holding the remaining sample components on the surface after the solvent has been removed by the heater 12 is used as a differential pressure exhaust means 1.
3 into the ionization chamber 1. This differential pressure evacuation means has chambers 15a, 15b formed by partition walls 14a, 14b, 1014c, and each chamber is connected to an appropriate vacuum pump 16a, 16b depending on the degree of vacuum. The belt 6 is then transferred to the ionization chamber or into the atmosphere through passages provided in each partition, but the circulation of air in this section is extremely small, which deteriorates the degree of vacuum in the ionization chamber. Heald can be transported without any trouble. The belt 6 transferred into the ionization chamber 1 in this manner is irradiated with a high-speed neutral particle beam 19 from a neutral particle source 18, which will be described later, in the ionization section 17 set between the pulleys 7 and 8. The sample components held on the surface of the belt 6 are ionized by the beam irradiation and guided to the mass spectrometry system via the extraction electrode 2, the focus electrode 3, and the main slit 4. It is used to create a given neutral particle beam, for example, an argon atomic beam, and includes an argon ion gun 21 for introducing argon gas, ionizing it by electron impact, and accelerating it to obtain an argon ion beam 20; It is composed of a collision chamber 22 for colliding with floating argon gas to deprive the argon ions of electric charge, and a deflector 23 for extracting the argon ions that have not been deprived of the electric charge mixed in the argon atomic beam emitted from the collision chamber 22. be done.

In order to facilitate the irradiation of the argon atomic beam and the extraction of ions, the pulleys 7 and 8 are positioned so that the belt surface force bow 1 between the pulleys 7 and 8 is inclined (for example, about 45 f) with respect to the output electrode 2. This is taken into consideration, and a perforated plate 24 is placed in that area to limit the irradiation area of the argon atomic beam. Further, 25 is a heater for evaporating and removing sample components remaining without being ionized. In the above-described configuration, the pulleys 7, 8, and 9 are rotated in the direction of the arrow, and the belt is passed through the differential pressure evacuation means 13 at a constant speed. If the liquid effluent from the liquid chromatograph 10 is applied to the belt in the sample applying section 11 while being transferred by the liquid chromatogram, the liquid effluent is developed as a liquid chromatogram on the belt.

The solvent component is removed from the expanded effluent by the heater 12, and only the remaining sample components are held on the belt and sequentially transferred to the ionization section 17, where they are ionized by irradiation with an argon atomic beam and subjected to mass spectrometry. Ru. At this time, in the ionization section 17, the sample is ionized by colliding high-speed argon atoms (neutral particles) with the sample, so there is no need for the conventional vaporization process by heating, and the sample is not decomposed due to heat. It is possible to eliminate it. Therefore, accurate measurements can be made even with unstable samples. Furthermore, since the sample is ionized by collision with high-speed argon atoms, even non-volatile substances or insulators can be efficiently ionized, and the range of samples that can be measured is expanded. In this embodiment, the argon ions taken out by the deflector 23 are irradiated onto the belt after measurement to splatter the belt, and the remaining sample that has not been ionized can be removed. can be lost. In the embodiments described above, argon atoms were used as neutral particles, but the present invention is not limited to this, and other atoms or neutral particles may be used.

[Brief explanation of the drawing]

The drawing is a sectional view showing the configuration of one embodiment of the present invention.
...Ionization chamber, 5, 16a, 16b...
・・Vacuum pump, 6・・・・Belt, 7, 8, 9・
... Pulley, 10 ... Liquid chromatograph, 11 ... Sample attachment part, 12, 25 ...
...Heater, 13...Differential pressure exhaust means, 14a,
14b, 14c...Partition wall, 15a, 15b...
...Room, 17...Ionization section, 18...
...Neutral particle source, 19...Neutral particle beam, 20...Argonion beam, 21...
...Argon ion gun, 22...Collision chamber, 2
3...Deflector, 24...Perforated plate.

Claims (1)

[Claims] 1. An evacuated ionization chamber, a belt that is continuously transferred to the ionization chamber from outside the vacuum, a differential pressure exhaust means provided at the introduction part of the belt into the ionization chamber, and a belt that is continuously transferred to the ionization chamber from outside the vacuum. means for depositing a sample solution;
an ion gun, a means for removing the electric charge of ions generated from the ion gun and converting them into neutral particles, and a neutral particle beam that is irradiated from the converting means onto the belt in the ionization chamber. a deflection means for extracting ions;
It is characterized by comprising an electrode for extracting and accelerating sample ions obtained by neutral particle irradiation, and irradiating the belt with the ions extracted from the neutral particle beam by the deflection means. The ion source of the mass spectrometer.