JPS6240150A - Flight-time-type mas spectrometer - Google Patents

Abstract

PURPOSE:To enable a study of high pressure on the stability of ions, by providing through holes in a reflection electrodes for reflecting accelerated ions to an ion detector, so that the through hols extend along the direction of acceleration of the ions, and by providing a neutral particle detector downstream to the reflection electrodes. CONSTITUTION:The foremost of reflection electrodes 4, which constitute an ion reflector 8, are meshy, while the others are annular. The reflection electrodes 4 have through holes 4a extending along the direction of acceleration of ions. A neutral particle detector 6 is provided downstream to the reflection electrodes 4 to detect nautral particles passed through the holes 4a of the ions reflector 8.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a time-of-flight mass spectrometer.

<Prior art> Time-of-flight mass spectrometer (hereinafter referred to as TOF-MS)
In general, ions are generated from the sample by irradiating the sample with pulsed laser light, etc., and the ions are accelerated under a predetermined accelerating voltage and flown in a predetermined direction to a detector. , its mass can be determined from the time required for it to reach the detector.

Among conventional ToF-MS, what is called a straight type is configured to accelerate ions extracted from a sample using an accelerating electrode, make them fly in a straight line, and cause them to enter a detector.

In addition, in conventional TOF-MS equipped with an ion reflector, ions are similarly accelerated by an accelerating electrode to fly in a straight line, and an electric field that can focus the energy of the ions is formed at a predetermined flight distance. An ion reflector having a reflecting electrode is disposed, and is configured to reflect incoming ions in a predetermined direction and cause them to enter the ion detector.

<Problems to be Solved by the Invention> By the way, even if ions are generated, if their lifetime is short, some of the ions may undergo fragmentation during flight. When such ions are analyzed by conventional straight TOF-MS, if fragmentation occurs in an electric field-free space, the resulting neutral particles will have the same velocity as the original ions, so the observed mass spectrum will change. This results in a mixture of both ion and neutral particle components.

On the other hand, when similar ions are analyzed using a TOF-MS equipped with a conventional ion reflector, only the ions are guided to the detector by the ion reflector, so the observed mass spectrum contains neutral particles due to fragmentation during flight. It does not contain ingredients that have become .

In order to examine the stability, or lifespan, of ions generated from a sample, we need a spectrum of only the ions that have reached the detector, and a spectrum of those that have undergone fragmentation and become neutral particles. becomes. Conventionally, when conducting such studies, a straight type T was used for the same sample.

It was necessary to perform separate analyzes using both F-MS and TOF-MS with an ion reflector to obtain a spectrum containing ions and neutral particles and a spectrum containing only ions. Furthermore, since the obtained magnitudes are obtained through separate analysis operations, there is a problem in that it is not possible to obtain an accurate comparison of the intensities.

The present invention was developed in view of the above, and allows the spectra of ions and neutral particles to be determined in a single analysis.By comparing these, it is possible to compare the intensities with high precision, and the stability of the ions can be determined. The purpose of this study is to provide a time-of-flight mass spectrometry needle that enables highly accurate studies regarding

Means for Solving the Problems> The configuration for achieving the above object will be explained with reference to FIG. 1, which is an embodiment drawing. In order to extract ions and make them fly, and to converge the energy of the ions at a predetermined flight distance and reflect them in a predetermined direction, a reflective electrode 4-4 that forms a predetermined electric field is provided, and the ions are directed in the direction of reflection of the ions. A detector 5 is provided, and after extracting ions, the ion detector 5
In an apparatus for determining the mass of an ion from the time required to reach ion, a through hole 4a is formed in the reflective electrode 4--4 in the direction of acceleration of the ions.

Moreover, a neutral particle detector 6 for detecting neutral particles that have passed through the through hole 4a is provided at the rear stage of the reflective electrode 4-4.

Effect> Ion number extracted from the sample and accelerated, reflecting electrode 4
---4 is guided to the ion detector 5 by the electric field. On the other hand, neutral particles that undergo fragmentation during the flight pass straight through the through hole 4a without being affected by the electric field, and are detected by the neutral particle detector 6. be done.

As a result, suppose that the mass vector l-/ of the ions actually generated and accelerated from sample W is as shown in Fig. 2(a), and some of them cause fragmentation. For example, a mass spectrum as shown in FIG. 2 (bl) is generated based on the detection signal from the ion detector 5, and a mass spectrum as shown in FIG. can be obtained simultaneously with the analysis operation of

By comparing the spectra of ions and neutral particles shown in FIG. 2(b) and (C1), it is possible to conduct a highly accurate study of the lifetime of the generated ions.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram showing the main part of an embodiment of the present invention.

A sample W to be analyzed is supported by a sample holder 1, and ions are generated by irradiating it with pulsed laser light, for example. The generated ions are accelerated rightward in the figure by the acceleration electrode 2 to which a predetermined acceleration voltage is applied, fly within the drift tube 3, and are guided to the ion reflector 8.

The ion reflector 8 is composed of a reflected voltage power source 7 that outputs a reflected voltage V=, and reflective electrodes 4--4 that are supplied with divided voltages of the reflected voltage vR, respectively.
Ion detection by concentrating the energy of incoming ions by forming an electric field with the opposite polarity to the accelerating voltage? It can lead to A5. The reflecting electrodes 4-4 constituting this ion reflector 8 have a mesh structure at the front and rear ends, and a ring shape between them. Hole 4a
will be formed.

A neutral particle detector 6 is disposed at the rear of the reflective electrode 4 - 4 of the ion reflector 8 and can detect neutral particles that have passed through the through hole 4 a of the ion reflector 8 .

According to the above-described embodiment of the present invention, ions generated from the sample W are guided to the ion reflector 8 through the drift tube 3, and the remaining ions are bent in their ilt path by the electric field and sent to the ion detector. Detected by 5. Furthermore, neutral particles that undergo fragmentation during flight pass through the through hole 4a and are detected by the neutral particle detector 6 without having their trajectories bent by the electric field. In other words, a single analysis operation simultaneously yields a mass spectrum of ions that have not undergone fragmentation and a mass spectrum of ions that have undergone fragmentation and become neutral particles.

As a result, ions A, B, C, and 'D were actually generated from sample W and accelerated, and their mass spectra are shown in Figure 2 (
If some of them were to undergo fragmentation during flight, the output from the ion detector 5 would result in a mass spectrum as shown in (b) of the same figure. From the output of the particle detector 6, a mass spectrum as shown in Figure 2 (C1) can be obtained.

By comparing the mass spectra shown in (C), the following considerations can be made, for example.

(2) Ion D exists, but it has the shortest life and the amount of ions produced is also small.

■Ion A is stable.

■Ion detectors produce the same amount, but ion C is more unstable, etc.

By the way, in conventional straight TOF-MS, the second
The mass magnitude shown in Figure fa) is obtained.

No information about the stability of ions A, B, C, and D can be obtained from this spectrum. In addition, in TOF-MS with a conventional ion reflector,
A mass spectrum shown in FIG. 2(b) is obtained. From this spectrum, it cannot be found that ion D was produced, and the stability of the ion is also unknown. Therefore, we prepared both types of TOF-MS,
When the same sample is analyzed separately, Figure 2 (al
(By obtaining the mass spectrum of bl, information regarding the presence of ion D and the stability of each ion can also be obtained,
ions because they are spectra from separate measurements.

Even if we compare the intensities of neutral particles, the result will be an inaccurate study, and we can only grasp trends.

<Effects> As explained above, according to the present invention, a through hole penetrating in the ion acceleration direction is formed in the reflective electrode that reflects accelerated ions and guides them to the ion detector, and the through hole of the reflective electrode A neutral particle detector is installed at the latter stage, so in a single analysis operation, a mass spectrum of ions extracted from the sample without fragmentation and a mass spectrum of ions that have undergone fragmentation and become neutral particles can be obtained. This made it possible to compare both spectra with high accuracy in terms of intensity, and it became possible to consider the stability of ions with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a main part of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of its operation. 1-sample holder, 2-.-acceleration electrode 3-.-drift tube, 4-reflection electrode 4a-through hole,
5-・Ion detector 6-Neutral particle detector, 7-
Reflected voltage power supply 8--Ion reflector

Claims (1)

[Claims] In order to extract ions from the sample under a predetermined acceleration and make them fly, and to converge the energy of the ions and reflect them in a predetermined direction over a predetermined flight distance, a reflecting electrode is provided to form a predetermined electric field. In an apparatus in which an ion detector is provided in the direction in which ions are reflected, and the mass of the ions is determined from the time required for the ions to reach the ion detector after being extracted, the reflecting electrode is penetrated in the direction in which the ions are accelerated. What is claimed is: 1. A time-of-flight mass spectrometer, characterized in that a through-hole is formed, and a detector for detecting neutral particles passing through the through-hole is provided downstream of the reflective electrode.