JPH0447892Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mass spectrometer, and particularly to the structure of a fixture for a sample holder thereof.

[Prior art]

In a mass spectrometer, a sample heating chamber and an adjacent ionization chamber are separated by a partition wall, and the vaporized sample introduction hole that runs between them is generally small in diameter.

The porous sample holder includes amorphous materials such as glass wool and asbestos, but these materials were simply accommodated in a recess provided at the tip of the sample introduction probe and pressed against the vaporized sample introduction hole.

[The problem that the invention is trying to solve]

Among porous sample holders, those that have a certain shape, such as an adsorbent layer formed on a support or a self-supporting porous adsorbent agglomerate, have a thickness that corresponds to the vaporized sample introduction hole. It is often impossible to insert the tube because it is larger than the inner diameter of the tube. In such a case, most of the vaporized sample is not led from the heating chamber to the ionization chamber, but is directly discharged from the heating chamber to the outside air, and the vaporized sample led to the ionization chamber is the polar part of the sample held in the holder. It is limited to a small area and degrades the sensitivity and accuracy of measurements.

[Means for solving problems]

The present invention was proposed in order to solve the above problems, and was designed to be movable together with the sample introduction probe within the sample heating chamber of the mass spectrometer.
In a sample holder fixing device for a mass spectrometer, which is electrically insulating as a whole and includes a cylindrical stem having a detachable connection part for a sample introduction probe at its base and a supporting part for a porous sample holder at its tip. The cylindrical stem is fitted with a thin cap made of a highly thermally conductive material, which is press-fitted to the stem at one end and is open at the other end to surround and cover the side surface of the sample holder. For a mass spectrometer, the interior of the cab is configured to communicate with the ionization chamber through a vaporized sample introduction hole provided in the partition when the open end touches the partition between the sample heating chamber and the adjacent ionization chamber. The gist is the sample holder fixture.

The cylindrical stem may be made of metal, glass, or plastic as long as it has a removable connection part for the sample introduction probe and a support part for the porous sample holder. but,
If the body is electrically conductive, the connections are preferably made of insulating plastic or rubber, for example. When the sample holder is a strip of a sintered thin layer chromatography plate, the support is preferably a resilient plastic tube capable of wrapping round a square cross section, for example. For example, polytetrafluoroethylene,
Examples include silicone, polyacetal, and polyimide. Depending on the case, the entire portion from the connection portion to the support portion may be integrally molded using these resins.

In addition, materials with good thermal conductivity constituting the thin-walled cap include aluminum, gold, copper, etc., and the thinner the molding is possible, the better, for example, 0.3
~0.4mm.

[Effect]

According to the present invention, the sides of the porous sample holder are surrounded and covered by thin caps during mass spectrum measurement, so that the sample is prevented from diffusing into the heating chamber and at the same time introduced into the ionization chamber. The ratio becomes larger, which improves the sensitivity and accuracy of the measurement.

〔Example〕

Figures 1 to 3 are all schematic cross-sectional views of embodiments of the sample holder fixing device for mass spectrometers of the present invention, and in each figure, 10 is a cylindrical stem, and 12 is its probe (not shown). 14 indicates a supporting portion of the porous sample holder 20. Further, 30 is a thin cap, 40 is a partition wall between the sample heating chamber and the ionization chamber, and 42 is a vaporized sample introduction hole.

The main body of the cylindrical stem 10 of the fixing device shown in FIG. 1 is a glass tube, while the main body of the cylindrical stem 10 of the fixture shown in FIG. The support portion 14 is a tube made of polytetrafluoroethylene. Here, the connection part 12 is a silicone material for gas chromatography that can be attached in place of the standard sample introduction probe of a Shimadzu mass spectrometer (QP-1000) after removing the part beyond the septum part. The rubber stopper is used as is.

In addition, the one in Figure 3 has a connecting part 12 and a supporting part 1.
4. Cylindrical stem 1 using flexible resin
This is a sample holder fixture that is integrally molded with 0.

Typically, the porous sample holder 20 is supplied as a strip of glass plate with a thin layer of porous thin layer chromatography (TLC) adsorbent. Therefore, the unnecessary part is cut off and inserted into the polytetrafluoroethylene tube of the support part 14 so that the spot of the TLC developed sample is located at the tip 22 of this strip.

Thereafter, a thin aluminum cap 30 is placed over this to seal the sample introduction chamber (not shown) in the front stage of the heating chamber, and with the introduction chamber sufficiently depressurized, the opening/closing port between the introduction chamber and the heating chamber ( (not shown) is opened to communicate between both chambers, and exhaustion of the heating chamber and ionization chamber is started. When the probe is advanced until the tip opening 32 of the thin cap 30 contacts the partition wall 40, the inside of the thin cap 30 communicates with the ionization chamber through the vaporized sample introduction hole 42 of the partition wall 40, and preparation for measurement is completed here.

In the embodiment shown in FIG. 2, the cylindrical stem 1
The reason why the periphery of the support part 14 of 0 is formed into a stepped part 16 is because the thin cap 30 can be easily attached.

Further, although the thin cap 30 is shown having a stepped portion 34 formed along the shape of the stored object, there is no need to be particularly particular about this shape, and it may be formed into any shape. Vaporized sample introduction hole 42 in partition wall 40
is normally provided at the center of the annular recess 44, so it is desirable that the outer diameter of the tip opening 32 of the cap 30 be small enough to fit within the recess 44. Note that if the vaporized sample introduction hole 42 faces the heating chamber and is chamfered around the introduction hole 42, it is more convenient for centering the sample holder fixture.

〔effect〕

Using the device shown in the example in Figure 1, mass spectrometry experiments were conducted under the next measurement conditions.
The effect of using 0 was confirmed.

Ionization chamber temperature: 210℃ Sample heating temperature: 230℃ Ionization voltage: 70V Model used: Hitachi M-80 As a result, the holder 2 has a TLC thin layer with hydrocortisone (15μg) attached to the tip 22.
The ionic strength of M ⁺ (M/Z362) using 0 is
By installing Cap 30, the height was increased by 4 times and the area increased by 15 times.

As described above, the present invention has a great practical effect despite its extremely simple structure.

[Brief explanation of the drawing]

1 to 3 are schematic cross-sectional views of a sample holder fixing device for a mass spectrometer in which the present invention is implemented. 10...Cylindrical stem, 12...Connection part, 14
...Bearing part, 16, 34...Stepped part, 20...Porous sample holder, 22...Tip, 30...Thin cap, 32...Opening, 40...Sample heating chamber and ionization chamber Partition wall between, 42... vaporized sample introduction hole, 44... annular recess.

Claims (1)

[Scope of utility model registration request] It is electrically insulating as a whole and can be moved together with the sample introduction probe in the sample heating chamber of the mass spectrometer, with a removable connection part for the sample introduction probe at its base and a porous sample holder at its tip. In a sample holder fixing device for a mass spectrometer including a cylindrical stem having a support, the cylindrical stem includes:
A thin cap made of a highly thermally conductive material is attached to the stem, and the other end is open and is crimped and engaged at one end and surrounds and covers the side surface of the sample holder, and the open end of the cap is connected to the sample heating chamber. A sample holder fixing device for a mass spectrometer, which is configured such that the inside of the cap can communicate with the ionization chamber through a vaporized sample introduction hole provided in the partition wall when it comes into contact with the partition wall between the adjacent ionization chamber.