JP3799317B2 - Column positioning method and jig for ion source for mass spectrometer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for positioning a column of an ion source for a mass spectrometer, and more specifically, an inner chamber that is disposed in a vacuum vessel and generates ions therein, and the inner chamber can be detachably fixed and held. The present invention relates to a column positioning method for an ion source for a mass spectrometer configured to be able to take out an inner chamber from the vacuum container while the base chamber remains in the vacuum container.
[0002]
[Prior art]
Conventionally, an ion source for a mass spectrometer configured so that a filament and an ionization chamber can be taken out to the atmosphere without breaking a vacuum inside the mass spectrometer has been proposed (for example, see Patent Documents 1 to 6).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 52-84793 [Patent Document 2]
Japanese Patent Laid-Open No. 54-109895 [Patent Document 3]
JP-A-57-202054 [Patent Document 4]
JP 61-82647 A [Patent Document 5]
Japanese Utility Model Publication No. 1-86058 [Patent Document 6]
JP, 6-68842, A In a gas chromatograph mass spectrometer provided with such a type of ion source, when the column of a gas chromatograph has to be replaced due to contamination or wear, When it is necessary to replace a plurality of columns depending on the type, positioning of the insertion depth of the column into the ion source may be important. If the insertion depth of the column into the ion source is not reproducible, the ionization efficiency of the sample gas supplied from the column in the ion source will not be reproducible. This is because no longer appears. Therefore, conventionally, in order to perform positioning of the column with high reproducibility, the following method has been employed.
[0004]
FIG. 1 is a diagram showing a conventional technique of a column positioning method for an ion source for a mass spectrometer. An ion source placed in an ion source casing (vacuum vessel) D includes an inner chamber K that generates ions therein, and a base chamber J that is configured to detachably fix and hold the inner chamber K. It consists of two assemblies, and it is comprised so that the inner chamber K can be taken out of the ion source casing D, leaving the base chamber J in the ion source casing D. Incidentally, regarding the inner chamber K and the base chamber J, a patent application has already been filed by the applicant as Japanese Patent Application No. 2002-300206.
[0005]
The tip position of the capillary column B inserted into such an ion source is desirably set as close as possible to the ionization chamber M in order to improve the ionization efficiency of the ion source. However, since there must be no obstacle to the entry / exit when the inner chamber K is attached / detached, the tip of the capillary column B must not protrude into the inner hole of the base chamber J into which the inner chamber K is fitted.
[0006]
However, the tip of the capillary column B is located inside the ion source casing D, the guide pipe I, and the base chamber J. Further, a partition valve E and a preliminary exhaust chamber F are provided on the front surface, and an analysis portion V is provided on the rear surface. It is impossible to confirm the position of the tip of the capillary column B from the outside of the apparatus because the detectors are connected to each other and are made of an opaque material.
[0007]
For this reason, in the prior art, first, the inner chamber K is first pulled out to the atmosphere with the detachable rod G, then the vent valve S and the gate valve E are opened, and the inside of the ion source casing D in a vacuum state is made large. At atmospheric pressure, the gate valve E and the preliminary exhaust chamber F were removed from the ion source casing D together with the flange P, and the front surface was opened.
[0008]
Then, the inner hole portion of the base chamber J is made visible, and the capillary column B extending from the gas chromatograph C side is inserted through the inner side of the guide pipe I, and the distal end thereof comes into contact with the distal end of the guide pipe I. After confirming that the position before the sample introduction port L, that is, the position where it does not pop out toward the inner hole of the base chamber J into which the inner chamber K is fitted, the column nut Q is tightened, and the capillary column B The tip position of was fixed.
[0009]
Thus, after the column is fixed, the flange P is attached to the ion source casing D again, the vent valve S is closed, the gate valve E is opened, the pre-exhaust chamber F and the ion source casing D are evacuated, and the column is attached. Had ended.
[0010]
[Problems to be solved by the invention]
As described above, in the conventional technique, when the capillary column has to be replaced due to contamination or wear, or when a plurality of capillary columns need to be replaced depending on the type of analyte, the base chamber is used. In order to confirm the tip position of the capillary column B inserted into J, it was necessary to remove the front flange P of the ion source casing D and expose the ion source to the atmosphere.
[0011]
And it takes time to remove and replace such a front flange P, and since it takes a waiting time to start up the ion source casing D by evacuation, efficient measurement is possible. could not.
[0012]
In addition, since the setting of the tip position of the capillary column B depends on visual observation, the position reproducibility is uncertain, and when the ion source is exposed to the atmosphere, the components constituting the ion source are gas molecules and water vapor. For example, the contamination of the ion source is promoted to adsorb the ion, and the positioning of the capillary column B becomes a factor that makes the sensitivity of the mass spectrometer unstable or decreases.
[0013]
In view of the above-described points, an object of the present invention is to provide an ion source for a mass spectrometer capable of positioning the tip position of the capillary column B with good reproducibility without breaking the vacuum of the ion source casing D or relying on visual observation. And a column positioning jig for an ion source for a mass spectrometer.
[0014]
[Means for Solving the Problems]
In order to achieve this object, a column positioning method for an ion source for a mass spectrometer according to the present invention includes:
An inner chamber that is arranged in a vacuum vessel and has a sample introduction port into which a sample gas supplied from a column can be introduced, and ionizes the sample gas introduced from the sample introduction port. It consists of a base chamber that can be detachably fixed and held, and has an insertion means that can be inserted into the inner chamber so that the column can be inserted into the inner chamber. A column positioning method of an ion source for a mass spectrometer configured to be able to take out the inner chamber out of a vacuum container while
When inserting a column from the base chamber to the inner chamber, instead of the inner chamber, a column positioning jig that has the same outer shape as the inner chamber and does not have a sample inlet is fixed to the base chamber in advance. -After being held, the column is inserted until it hits the column positioning jig, and the insertion depth of the column is aligned.
[0015]
Further, a column positioning jig for the ion source for a mass spectrometer according to the present invention is:
A sample introduction port through which a sample gas supplied from a column can be introduced; an inner chamber that ionizes the sample gas introduced from the sample introduction port; and the inner chamber can be detachably fixed and held; and A base chamber provided with an insertion means for inserting the column toward the inner chamber at a position in contact with the sample introduction port of the inner chamber, and the inner chamber is left in the vacuum container while the base chamber remains in the vacuum container. A column positioning jig for an ion source for a mass spectrometer configured to be removed outside,
The shape is characterized by having a part having the same shape and the same size as the outer shape of the inner chamber, and having a blind plug structure having no sample inlet at that part.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an embodiment of a column positioning method for an ion source for a mass spectrometer according to the present invention. In this embodiment, the components constituting the gas chromatograph mass spectrometer such as the gas chromatograph C, the column interface V, the guide pipe I, the ion source casing D, the base chamber J, the inner chamber K, and the preliminary exhaust chamber F are the conventional components. It is exactly the same as technology.
[0017]
In the present invention, the only element different from the prior art is the column positioning jig T having a hook groove U at one end. The column positioning jig T is a positioning jig having a simple blind plug structure that has a part having the same shape and the same dimensions as the outer shape of the inner chamber K, and does not have the sample introduction port L and the ion repeller O at the part. is there.
[0018]
This embodiment operates as follows. First, with the gate valve E in the “open” state, the tip of the detachable rod G is hooked on the hook metal fitting H of the inner chamber K, and the inner chamber K is taken out to the preliminary exhaust chamber F. Next, the gate valve E is set to the “closed” state, the atmosphere is introduced from the vent valve S into the preliminary exhaust chamber F, the lid of the preliminary exhaust chamber F is opened, and the inner chamber K is taken out into the atmosphere.
[0019]
Instead of the inner chamber K, the hooking groove U of the column positioning jig T is fitted into the tip of the detachable rod G, put into the preliminary exhaust chamber F, and the cover of the preliminary exhaust chamber F is closed. The vent valve S is closed and the preliminary exhaust chamber F is evacuated. When the degree of vacuum in the preliminary exhaust chamber F reaches a predetermined value, the gate valve E is opened and the column positioning jig T is inserted into the ion source casing D. The column positioning jig T is accommodated in an inner hole portion (a hole in which the inner chamber K is accommodated) of the base chamber J. At this time, the detachable rod G is not removed and remains fitted in the hooking groove U of the column positioning jig T.
[0020]
When the capillary column B is inserted into the guide pipe in the ion source casing D from the gas chromatograph C side via the column interface V, the column positioning jig T has a blind plug structure. It hits the positioning jig T and becomes a dead end.
[0021]
This dead end position is understood as the position where the tip of the capillary column B does not jump out into the inner hole of the base chamber J, and is closest to the inner chamber K without any trouble in the insertion and removal of the inner chamber K. The position of the capillary column B is fixed by tightening the column nut Q and the sealing ferrule R.
[0022]
When the column nut Q has been tightened, the column positioning jig T is removed from the base chamber J with the detachable rod G, and the column positioning jig T is taken out into the preliminary exhaust chamber F with the gate valve E in the “open” state. . Next, the gate valve E is set to the “closed” state, the atmosphere is introduced from the vent valve S to the preliminary exhaust chamber F, the lid of the preliminary exhaust chamber F is opened, and the column positioning jig T is taken out into the atmosphere.
[0023]
Instead of the column positioning jig T, the hooking groove U of the inner chamber K is fitted into the tip of the detachable rod G, put into the preliminary exhaust chamber F, and the cover of the preliminary exhaust chamber F is closed. The vent valve S is closed and the preliminary exhaust chamber F is evacuated. When the degree of vacuum in the preliminary exhaust chamber F reaches a predetermined value, the gate valve E is opened and the inner chamber K is inserted into the ion source casing D. The inner chamber K is accommodated in the inner hole portion of the base chamber J.
[0024]
Finally, the tip of the detachable rod G is removed from the hooking groove U of the inner chamber K, the detachable rod G is extracted from the ion source casing D, and the gate valve E is brought into a “closed” state.
[0025]
By the above procedure, the tip position of the capillary column B can be positioned with high reproducibility with respect to the inner chamber K while the inside of the ion source casing D is always kept in a vacuum.
[0026]
【The invention's effect】
As described above, according to the column positioning method of the ion source for a mass spectrometer of the present invention, the ion source is disposed in the vacuum vessel and includes a sample introduction port into which the sample gas supplied from the column can be introduced. An inner chamber that ionizes the sample gas introduced from the sample inlet, and a guide pipe that can be detachably fixed and held and the column can be inserted toward the inner chamber. And a column positioning method for an ion source for a mass spectrometer, wherein the inner chamber can be taken out of the vacuum container while the base chamber remains in the vacuum container. In order to insert the column from the base chamber to the inner chamber Instead of the inner chamber, a column positioning jig that has the same outer shape as the inner chamber and does not have a sample introduction port is fixed and held in the base chamber in advance. The column is inserted until it hits the tool, and the insertion depth of the column is aligned, so that the tip position of the capillary column can be positioned with good reproducibility without breaking the vacuum of the ion source casing or relying on visual inspection. I was able to do it.
[Brief description of the drawings]
FIG. 1 is a diagram showing a conventional column positioning method of an ion source for a mass spectrometer.
FIG. 2 is a diagram showing a column positioning method of an ion source for a mass spectrometer according to the present invention.
[Explanation of symbols]
A ... Sample inlet, B ... Capillary column, C ... Gas chromatograph, D ... Ion source casing (vacuum vessel), E ... Gate valve, F ... Pre-exhaust chamber, G ... Detachable rod, H ... Hook, I ... Guide pipe, J ... Base chamber, K ... Inner chamber, L ... Sample inlet, M ... Ionization chamber , N ... heater, O ... ion repeller, P ... flange, Q ... column nut, R ... ferrule, S ... vent valve, T ... column positioning jig, U ... Hook groove, V ... Column interface.

Claims (2)

An inner chamber that is arranged in a vacuum vessel and has a sample introduction port into which a sample gas supplied from a column can be introduced, and ionizes the sample gas introduced from the sample introduction port. It consists of a base chamber that can be detachably fixed and held, and has an insertion means that can be inserted into the inner chamber so that the column can be inserted into the inner chamber. A column positioning method of an ion source for a mass spectrometer configured to be able to take out the inner chamber out of a vacuum container while
When inserting a column from the base chamber to the inner chamber, instead of the inner chamber, a column positioning jig that has the same outer shape as the inner chamber and does not have a sample inlet is fixed to the base chamber in advance. A column positioning method for an ion source for a mass spectrometer, wherein the column is inserted and held until it hits the column positioning jig, and the insertion depth of the column is aligned. A sample introduction port through which a sample gas supplied from a column can be introduced; an inner chamber that ionizes the sample gas introduced from the sample introduction port; and the inner chamber can be detachably fixed and held; and A base chamber provided with an insertion means for inserting the column toward the inner chamber at a position in contact with the sample introduction port of the inner chamber, and the inner chamber is left in the vacuum container while the base chamber remains in the vacuum container. A column positioning jig for an ion source for a mass spectrometer configured to be removed outside,
A column for an ion source for a mass spectrometer, characterized in that it has a part of the same shape and dimensions as the outer shape of the inner chamber, and has a blind plug structure without a sample inlet at that part. Positioning jig.

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