JPH09251849A - Mass spectrometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mass spectrometer with its high sensitivity by preventing ion loss until an ion transportation lens is reached. SOLUTION: Ions generated by means of atmospheric pressure ion source 1 are induced to a mass spectrometric system 4 via a sampling cone 2 and a schema cone 3 and mass-spectrometrically. A lens 5 composed of four electrodes to which high-frequency voltages are applied is arranged in a area between the schema cone 3 and the mass spectrometric system 4. A pipe 6 is so mounted on the side of the lens 5 of the schema cone 3 by means of welding, for example, as to communicate with an inducing hole. The other end of this pipe 6 reaches the interior of the lens 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mass spectrometer in which ions generated under a relatively high pressure are introduced into a vacuum chamber for mass analysis.

[0002]

2. Description of the Related Art The interior of a mass spectrometer is evacuated to 1
It is maintained at 0 ^-5 Torr about or less pressure. On the other hand, there are atmospheric pressure ion sources that generate ions by mass spectrometry at or near atmospheric pressure. When this atmospheric pressure ion source is combined with a mass spectrometer, the ions generated at atmospheric pressure are introduced into a high-vacuum mass spectrometer through a sampling cone and skimmer cone with small inlet holes while maintaining a pressure difference. Is being done.

Further, in order to prevent the loss of ions when the ions introduced into the vacuum through the sampling cone and the skimmer cone are transported to the mass spectrometry system, for example, it is composed of four rod-shaped electrodes to which a high frequency voltage is applied. A lens for ion transport is installed.

[0004]

SUMMARY OF THE INVENTION The present invention is highly effective in preventing the loss of ions until reaching the lens for ion transport, which is inevitable even in the mass spectrometer equipped with the lens for ion transport. An object is to provide a mass spectrometer that can obtain sensitivity.

[0005]

To achieve this object, the mass spectrometer of the present invention comprises an atmospheric pressure ion source and a hole for introducing ions generated by the atmospheric pressure ion source into a vacuum chamber. Introducing means provided, a mass analyzer for mass-analyzing the ions introduced into the vacuum chamber, an ion transport lens arranged between the mass analyzer and the introducing means, the introducing means and the ion transporting It is characterized in that it has an ion transport tube which is arranged in an ion passage between the lens for use and an ion, and which guides ions through the inside from the introducing means to the ion transport lens.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing an example of a mass spectrometer according to the present invention. In FIG. 1, an atmospheric pressure ion source 1 produces ions I under atmospheric pressure by the principle of electrospray ionization, for example. The generated ions are introduced into the vacuum-exhausted region through the introduction holes formed in the sampling cone 2 and the skimmer cone 3, and are introduced into the quadrupole type or magnetic field type mass analysis system 4 for mass analysis. It

Each region through which the ions pass is, for example, 1 in the region A between the sampling cone 2 and the skimmer cone 3.
Torr, about 10 ⁻³ Torr in region B between skimmer cone 3 and mass spectrometer 4, 1 in region C with mass spectrometer 4
It is evacuated by an appropriate vacuum pump so as to be maintained at about 0 ^-6 Torr.

In a region B between the skimmer cone 3 and the mass analysis system 4, an ion transport lens 5 is arranged in order to prevent a loss due to diffusion of ions. The lens 5 is composed of four rod-shaped electrodes arranged parallel to the ion passage and at 90 ° intervals so as to surround the ion passage, and a high frequency voltage is applied to each electrode.

On the lens 5 side of the skimmer cone 3, as shown in FIG. 2, a pipe 6 made of, for example, stainless steel is attached by, for example, welding so as to communicate with the introduction hole. The other end of the pipe 6 reaches the inside of the lens 5.

In the above-mentioned structure, the ions generated by the ion source 1 and introduced into the region B through the sampling cone 2 and the skimmer cone 3 reach the lens 5 through the inside of the pipe 6, and therefore this pipe is used. The loss when passing between the skimmer cone 3 and the lens 5 can be made extremely small as compared with the conventional case in which the lens is not provided. Therefore, it became possible to perform mass spectrometry with high sensitivity.

Although the pipe is directly attached to the skimmer cone 3 in the above-mentioned embodiment, it is not always necessary. For example, by using another holding means, it can be arranged apart from the skimmer cone 3. The distance between the pipe and the skimmer cone is preferably within 10 mm, and more preferably within 5 mm in order to prevent leakage of ions and gas molecules from the gap. When separating the pipe from the skimmer cone like this,
By applying an appropriate voltage to the pipe, it is possible to further increase the ion passing efficiency.

In the above embodiment, the tip of the pipe is inserted into the inside of the lens. However, if the tip reaches near the entrance of the lens, the tip does not necessarily reach inside.

Furthermore, in the above-described embodiment, the ion transport lens composed of four electrodes is used, but an ion transport lens having a larger number of electrodes may be used.

[0014]

As described in detail above, according to the present invention, the ions are passed through the inside of the ion passage between the introducing means for introducing the ions from the ion source into the vacuum chamber and the ion transport lens. Since the ion transport tube leading from the introducing means to the lens for ion transport is provided, it is possible to prevent the loss due to the diffusion of the ions and realize the mass spectrometer with high sensitivity.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a mass spectrometer according to the present invention.

FIG. 2 is an enlarged view showing a structure of a pipe portion in the apparatus of FIG.

[Explanation of symbols]

1: Atmospheric pressure ion source 2: Sampling cone
3: Skimmer cone 4: Mass spectrometric system 5: Lens 6: Pipe

Claims (2)

[Claims] 1. An ion source, an introduction means having a hole for introducing ions generated by the ion source into the vacuum chamber, and a mass analyzer for mass-analyzing the ions introduced into the vacuum chamber. An ion transport lens disposed between the mass spectrometer and the introduction means, and an ion passage disposed between the introduction means and the ion transport lens, through which ions pass from the introduction means to the ions. A mass spectrometer comprising an ion transport tube leading to a transport lens. 2. One end of the ion transport pipe is attached to the introducing means so as to be connected to an introducing hole of the introducing means,
The mass spectrometer according to claim 1, wherein the other end is inserted into the lens for ion transport.