JPH01299454A - Ionization mass spectrometer used under atmospheric pressure - Google Patents

Abstract

PURPOSE:To make it possible to perform fine atomization stably, by providing a structure wherein many small holes are provided along the axial direction in a specimen introducing pipe, introducing specimen that is conveyed into a spectrometer into said holes, and atomizing the specimen. CONSTITUTION:A specimen which is eluted from a liquid chromatograph 1 and a moving-phase material are sent into an atomizing part 3 and heated therein. Thus, the specimen and the material are atomized. The atomized specimen and the moving-phase material become a molecular state. The moving-phase material becomes the molecular state in an ionizing chamber. The material is ionized by corona discharge. The ionized moving molecules ionize the specimen molecules. A specimen introducing pipe 10 is inserted into a heater block 11. For example, six holes are arranged in a radial pattern in the cross sectional plane of the pipe 10. It is desirable that the diameter of the hole is 0.01-0.05mm. In this constitution, the surface areas of the inner walls of the holes are multiplied, and the distance from the inner wall of the hole to the center of the hole can be shortened. Therefore, the fine atomization can be realized stably.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is directed to atmospheric pressure ionization (Atomosphere).
The present invention relates to an atmospheric pressure ionization mass spectrometer that has an ionization function that utilizes molecular reactions such as pressure ionization or ionization, and particularly relates to an atmospheric pressure ionization mass spectrometer that has an improved sample introduction pipe that atomizes the sample or mobile phase.

rPrior art] A liquid chromatograph directly connected atmospheric pressure ionization mass spectrometer (hereinafter abbreviated as API) that utilizes atmospheric pressure ionization (hereinafter abbreviated as API).
A gas chromatograph direct-coupled mass spectrometer (hereinafter referred to as GC/API mass spectrometer) that uses conventional electron impact ionization (hereinafter referred to as EI)
Compared to the EI mass spectrometer), its ionization mechanism uses a gentler ionization method with less impact, so there is less decomposition when ionizing the sample, resulting in 1 trillion single molecule ions! It has easy-to-use characteristics, and
It has many advantages not available with C/EI mass spectrometers.

Such a LC/AP I mass spectrometer is a liquid chroma 1
- The sample and mobile phase eluted from the graph (hereinafter abbreviated as LC) are guided to the atomization section, where heat is applied to make the sample into a molecular state, and the sample is further ionized by corona discharge in the ionization chamber. After that, mass spectrometry will be performed.

[Problem that the invention seeks to solve]

However, in the above conventional technology, the atomization section has a diameter of 0.
A sample introduction pipe having one 1rIn hole and a heater block were integrated, and the sample and mobile phase were atomized by heating the heater block. Therefore, in order to stably obtain fine atomization, the flow rates of the sample and mobile phase and the temperature of the heater block have subtle effects, making it extremely difficult to set the temperature of the heater block. In an LC/API mass spectrometer, one of the factors for performing mass spectrometry with high sensitivity is how stably and finely a sample and mobile phase can be atomized.

An object of the present invention is to provide an atmospheric pressure ionization mass spectrometer that stably and finely atomizes a sample and a mobile phase to perform highly sensitive mass spectrometry.

[Means to solve the problem]

In order to achieve the above object, the present invention includes: an atomization unit that heats and atomizes a sample transported by a mobile phase within a sample introduction pipe; an ionization unit that ionizes the atomized sample; In an atmospheric pressure ionization mass spectrometer equipped with a mass spectrometer that analyzes the mass of an ionized sample, the sample introduction pipe has a structure in which many fine holes are provided along the axial direction, and the sample is transported by a mobile phase. The sample is introduced into the hole and atomized.

Further, the hole provided in the sample introduction pipe is formed circularly or radially, and the diameter of the hole is 0.0.
It is formed from 1nn+ to 0.05nn.

In addition, the sample introduction pipe may be inserted into a thin-walled pipe by inserting a plurality of thin rod-like bodies in close contact with each other, or by placing a plurality of thin rod-like bodies in close contact with each other, and the outer periphery of the closely-contacted rod-like bodies is It can be formed by winding a plate or inserting a porous metal body or porous sintered body into a thin-walled pipe.

[Effect]

According to the above configuration, the contact area between the sample or the mobile phase and the inner surface of the hole in the sample introduction pipe becomes larger, which makes it possible to apply more heat to the sample or the mobile phase, and the inner surface of the hole. It is possible to reduce the temperature gradient between the hole and the center of the hole, and it is possible to realize uniform, stable, and finer atomization.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

The outline of the atmospheric pressure ionization mass spectrometer according to the present invention is shown in FIG. It is atomized by adding . The atomized sample and mobile phase are in a molecular state and are ionized by corona discharge generated from the needle electrode 5 in the ionization chamber 4 . The ionized mobile phase molecules cause a molecular reaction with the sample molecules and ionize the sample molecules by transferring protons to the sample molecules that have not yet been ionized. This molecular reaction gently ionizes almost all of the sample molecules. The ionized sample molecules pass through the first pore and further through the second pore 7, and are sent to a mass spectrometer 8 where they are subjected to mass spectrometry.

The second section shows the detailed configuration from the LCI to the atomization section 3.
It is a diagram. As shown in the figure, a Teflon pipe 2 for guiding the sample or mobile phase eluted from the LCI is connected to a sample introduction pipe 10 by a joint 9 using a Swagelock screw. The sample introduction pipe 10 is inserted into a heater block 11, and a spacer 12 is installed between the heater block 1.1 and the sample introduction pipe 10 to improve heat conduction. A heater 13 for heating the sample introduction pipe 10 and a temperature detection element 14 for detecting the temperature are attached to the heater block 11, so that an arbitrary and constant temperature can be applied to the sample or the mobile phase.

The cross section of the sample introduction pipe 10 is formed as shown in FIG. In this example, there are 6 holes with a diameter of 0.04 m in a ceramic material with an outer diameter of 1°611 fl and a length of 150 nm.
They are arranged radially. This is hiter block 11
This is to minimize variations in the heat applied to each hole. According to this method, the conventional hole diameter is 0.1 na.
When compared to be able to. Therefore, the actual flow rate from LCI is 0°8~1
, 0 cc/min, the temperature of the heater block 11 is 300 to 350°C, which is the conventional temperature of 38°C.
Stable and finer atomization can be obtained at temperatures lower than 0 to 400°C, and sensitivity can also be improved by 5 to 10 times compared to conventional methods.

In this example, ceramic was used as the material, but this is not necessarily a good method since it has the effect of chemically activating the sample and the like. However, with the current technology, the only way to pass a hole with a diameter of 0.0 L to 0.05 [ID] over a length of 100 to 150 mm is to use ceramics. Therefore, it goes without saying that it would be effective if the sample introduction pipe shown in this example could be manufactured using gold (Au), which is the most chemically stable substance.

Furthermore, regarding the arrangement of the holes in this embodiment, FIG. 3 shows an example in which six holes are arranged radially, but as a method for uniformly applying the heat from the heater block 11 to the sample or mobile phase, It is also conceivable to arrange several holes in a circle as shown in FIG.

In addition, as a method of providing a plurality of fine holes, as shown in FIGS. 5 and 6, a plurality of fine rods made of stainless steel, for example, are inserted into a thin-walled pipe made of stainless steel, or It can also be manufactured by wrapping a fine rod made of, for example, stainless steel with a thin plate made of, for example, stainless steel. However, in the case of this method, it is difficult to intentionally arrange the thin holes as shown in Figures 3 and 4, and the arrangement becomes random. This may be more difficult than the cases shown in Figures 3 and 4.

Further, FIG. 7 shows a case in which a porous metal body or a sintered body is inserted into a thin-walled pipe made of stainless steel, for example. In this case, by changing the size of the particles constituting the metal body or sintered body, the size of the narrow holes can be changed, and even more holes can be provided. However, although it is possible to obtain a fine mist with this method, all of the sample or mobile phase sprayed from the tip does not necessarily fly straight toward the sample introduction direction (opposite the LC direction), and some may not enter the ionization chamber.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to stably realize fine atomization, so it is possible to improve the sensitivity of mass spectrometry by about 5 to 10 times compared to the conventional method.

Therefore, sensitivity adjustment of the LC/API mass spectrometer becomes easy, and analysis operations become very easy.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the LC/API mass spectrometer, Figure 2 is a detailed diagram of the sample introduction pipe, Figure 3 is a cross-sectional view of the sample introduction pipe of the present invention, and Figure 4 is a cross-section showing a modification thereof. Figure, 5th
6 and 7 are cross-sectional views showing other embodiments in which a plurality of holes are provided in the sample introduction pipe. 1...Liquid chromatograph, 3...Atomization section, 4...
Ionization chamber, 5... Needle electrode, 8... Mass spectrometry section, 1
0... Sample introduction pipe, 11... Heater block,
12 spacer, 13... heater, 14... temperature detection element.

Claims (1)

[Claims] 1. An atomization section that heats and atomizes a sample transported by a mobile phase in a sample introduction pipe, an ionization section that ionizes the atomized sample, and an ionization section that ionizes the atomized sample; In an atmospheric pressure ionization mass spectrometer equipped with a mass spectrometer that analyzes mass, the sample introduction pipe has a structure in which a large number of fine holes are provided along the axial direction, and the sample introduced by the mobile phase is An atmospheric pressure ionization mass spectrometer, characterized in that the sample is introduced into the hole and atomized. 2. The atmospheric pressure ionization mass spectrometer according to claim 1, wherein the holes provided in the sample introduction pipe are formed circularly or radially. 3. The diameter of the hole provided in the sample introduction pipe is 0.
The atmospheric pressure ionization mass spectrometer according to claim 1 or 2, characterized in that the diameter is from 0.01 mm to 0.05 mm. 4. The atmospheric pressure ionization mass spectrometer according to claim 1, wherein the sample introduction pipe is formed by inserting a plurality of thin rod-shaped bodies in close contact with each other into a thin-walled pipe. 5. Atmospheric pressure ionization according to claim 1, wherein the sample introduction pipe is formed by bringing a plurality of thin rod-like bodies into close contact with each other and wrapping a metal plate around the outer periphery of the closely-adhered rod-like bodies. Mass spectrometer. 6. The atmospheric pressure ionization mass spectrometer according to claim 1, wherein the sample introduction pipe is formed by inserting a porous metal body or a porous sintered body into a thin-walled pipe.