JPS592521Y2 - Continuous sample introduction device in mass spectrometer - Google Patents

Description

[Detailed explanation of the device] This device uses 10-4 to 1 in order to perform sample analysis, etc.
This relates to improvements to the sample introduction device in mass spectrometers, which are used to bring a sample into a vacuum chamber at about 0' Torr from outside at atmospheric pressure, perform analysis, and then take it outside the room. be.

Figure 1 schematically shows a direct sample introduction device, which is one of the conventional sample introduction devices used in mass spectrometers.The introduction and measurement of a sample into the analyzer using this device is as follows. It is done as follows.

That is, the sample container 1 containing the sample is set in the sample container accommodating portion at the tip of the sample introduction probe 2 via the coil spring installed inside the sample container 1, and then the probe 2 is
is inserted into the preparatory chamber 3 of the analyzer, and the preparatory chamber 3 is evacuated by opening the valve 4 of the conduit connected to an exhaust system consisting of a rotary pump and an oil diffusion pump separately provided, and the pressure reaches 10-
At the point when the exhaust air is evacuated to about 2 to 1 O-5 Torr, a valve (circle valve) 7 provided between the sample introduction section 6 containing the sample ionization chamber 5 and the preliminary chamber 3 is opened to airtightly isolate the chamber. In addition to connecting the left and right rooms,
The probe 2 is pushed into the introduction section 6 through the through hole of the opened valve 7, so that the end surface of the sample container 1 is pressed against the side surface of the ionization chamber 5 by the elastic force of the coil spring of the sample container accommodating section. set.

When the probe 2 is set as described above, the sample container 1 is heated by the coiled heater 8, and the sample contained in the sample container is vaporized to form a sample gas, which is introduced into the ionization chamber 5.

The introduced sample gas, not shown in the figure, is ionized by electrons emitted from the red-hot filament and emitted through window 9 toward the target.

The band-shaped ion flow accelerated by a voltage of several thousand volts applied to the ionization chamber 5 is focused onto the ion source slit 11 by the action of the lower lens electrode 10.

Although the ion beam passing through this slit 11 is not shown, it is mass-separated by a main magnet, passes through a collector slit, and the sample gas is subjected to mass analysis by an ion detector.

Next, we will talk about how to take the sample container outside the room using this device.
The probe 2 is pulled out to the right and taken out into the preliminary chamber 3, and then the valve 7 is closed to shut off the sample introduction section 6 and the preliminary chamber 3.

In this case, it goes without saying that the valve through-hole for the probe 2 is closed at the same time.

Close the valve 4 to disconnect the preliminary chamber 3 from the exhaust system, introduce the atmosphere into the preliminary chamber 3 to bring it to atmospheric pressure, then completely pull out the probe 2 outside the room and take out the sample container 1 outside. to recover.

Then, instead, the sample container 1 containing the next sample is loaded into the probe 2, the above-described sample introduction operation is repeated, and the sample is analyzed and measured again.

As mentioned above, with conventional sample introduction devices for mass spectrometers, a vacuum evacuation operation is required each time a sample is introduced into the analyzer. The preparation process accounts for a large proportion of 30 to 50% of the total time required, making it impossible to carry out highly efficient analysis and measurement, and the preparation process, which is performed using a vacuum aerodynamic device, must be repeated every time a sample is measured. I can't avoid it.

On the other hand, operating the vacuum aerodynamic device frequently means that trace amounts of oil from the vacuum pump and fine components of the atmosphere are brought into the ionization chamber 5 and ionized at 10' Torr.
It also provides an opportunity to carry the sample into the analysis tube, which is held at a much higher vacuum, and disturb the background of the measurement.

In view of the current situation described above, this invention was made with the purpose of solving the above-mentioned disadvantages of conventional sample introduction devices, and it is possible to transfer sample containers loaded with a plurality of sample containers through a vacuum air system. Te10-4~1
The inside of the sample introduction section is introduced into the sample introduction section maintained at O-7 Torr and left on standby, and the sample containers are successively inserted one by one from the sample container holder and operated from the outside while maintaining the internal vacuum level. In addition to being able to carry out sample measurements by introducing it into a predetermined position, the sample container can be easily collected after each measurement into a collection container maintained in a vacuum state by an external operation. It is an object of the present invention to provide a continuous sample introduction device for a mass spectrometer that can be operated efficiently.

Hereinafter, one embodiment of the device according to the invention will be described in detail with reference to the drawings.

FIG. 2 is a schematic explanatory diagram of this apparatus incorporated into a magnetic field type single focus mass spectrometer using a general thermionic impact type ion source.

Reference numeral 3 denotes a preparatory chamber, which is connected via a valve (not shown) to a pipe line connected to an exhaust system consisting of a rotary pump, an oil diffusion pump, etc.

Reference numeral 6 is a vacuum chamber that is always maintained at a vacuum level of 10-4 to 1O-7 Torr at the sample introduction part, and 7 and 7' are valves (circle valves) that can be attached to the valves by operating the handle 7''. The through-holes are opened and closed, and the chambers connected above and below are communicated with and shut off.

Ionization chamber 5, coiled heater 8, window 9, lens electrode 1
0 and the ion source slit 11 are the same as those shown in FIG. 1, so their explanation will be omitted.

12 is a sample container holder, 13 is a sample container loading operation rod, 14 is a sample introduction probe, and 15 is a sample container accommodating section (boat).

These will be explained based on the perspective view of FIG.

For convenience of explanation, sample container holder 1 is shown in FIG.
2 and its operating rod 13 are shown rotated by 90 degrees.

Reference numeral 21 denotes a support arm, to which is attached an elongated box frame 22, and on the right front side of the box frame 22, an L-shaped leaf spring 23, which serves as the bottom of the box, is fixed at its upper end.

That is, a loading box is formed by the box frame 22 and the leaf spring 23, and the sample containers 1' are stacked (seven in the figure) in the loading box.

On the opposite side of the support arm 21 to the side to which the box frame 22 is attached, a pushing plate spring 24 is fixed in a cantilever manner with its upper end, which is formed by bending the lower end of an inverted letter-shaped leaf spring 90 degrees to the side surface. ing.

A through slit 25 is provided at the same position at the lower end of the pushing leaf spring 24 and the opposing surface of the pushing leaf spring 24 of the box frame 22, respectively.

Reference numeral 26 denotes an L-shaped small leaf spring whose upper end is fixed to the pusher leaf spring 24, whose bent lower end is inserted into the slit 25, and whose tip is accommodated in the box frame 22. The tangent line between the bottom sample container 1' and the second sample container 1' from the bottom is oriented.

Reference numeral 15' denotes a small hole drilled at the tip of the boat 15, which serves as a sample gas introduction hole.

Reference numeral 27 denotes a sample gas introduction cylinder, which is provided inside the coiled heater 8, and its inner diameter is slightly larger than the outer diameter of the boat 15.

28. 28' is the operating rod 13 and the sample introduction probe 14
The seal 29 for each is a collection bottle for the sample container 1' having an opening at the upper end attached to the valve 7'.

Next, the operation of this device will be explained.

With the valve 7 closed, the sample container holder 12 loaded with a plurality of sample containers 1' containing samples is placed at 10-' to 1O-7T.
It is cut off from the introduction section 6, which is maintained at a vacuum level of orr, and inserted into the preliminary chamber 3, which is brought into an atmospheric pressure state.

Next, as mentioned above, although not shown in the figure, the valve connected to the exhaust pipe is opened to exhaust the preliminary chamber 3.
When the pressure reaches 10-2 to 1 O-5 Torr, open the valve 7 by operating the handle 7'', push the sample container holder 12 through the through hole to the position shown, and hold it at that position. .

Next, when the sample container loading operation rod 13 is pushed in the direction of the arrow with the knob at its tip against the elastic force of the coil spring, the fourth
As shown in the figure, the pushing leaf spring 24 pushes out the leaf spring 23 at the tips of the left and right bent parts at the bottom, and the bottom part of the box frame 22 is removed, so that the lowermost sample container 1
' is dropped, is received by the boat 15 of the sample introduction probe 14 waiting at a position below it, and is housed therein.

On the other hand, the remaining sample containers 1' in the holder 12 are held by the sample container holder 12 because the second one from the bottom is supported by the bent portion of the small leaf spring 26 that is pushed together with the push leaf spring 24. When the operating rod 13 is returned by the coil spring, the pushing leaf spring 24, the small leaf spring 26, and the leaf spring 23 are all restored by their respective elastic forces, returning to the initial state shown in FIG.

Next, the sample introduction probe 14 containing the sample container 1' is pushed to the left and inserted into the sample gas introduction cylinder 27, and the tip of the boat 15 is pressed against the side wall of the ionization chamber 5 and held in that position.

Then, the sample container 1' is heated by the coiled heater 8, and the sample therein is vaporized to form a sample gas.

This sample gas is prevented from diffusing upward by the sample gas introduction cylinder 27, and is introduced into the hole in the side wall of the ionization chamber 5 through the introduction hole 15'.

The introduction of the sample is thus completed, but the subsequent ionization of the sample gas and analysis and measurement of the ions have already been described and will therefore be omitted.

When the analysis and measurement of the sample is completed, the sample introduction probe 14 is returned to the original standby position, the valve 7' is opened by operating the handle 7'', and the sample introduction section 6 is opened to the same extent as the sample introduction section 6. A through hole in the valve 7' is opened to communicate with the sample recovery bottle 29 which is kept at a vacuum level of .

Then, when the sample introduction probe 14 is rotated 180 degrees from the standby position, the sample container 1' in the boat 15 is transferred to the valve 7'.
It is dropped into the collection bottle 29 through the through hole and collected.

For the introduction and recovery of the second and subsequent sample containers 1', the above-mentioned operations can be repeated, and in this way, each of the plurality of sample containers 1' loaded in the sample low-density holder 12 is removed. After analysis and measurement of the sample is completed, the sample container holder 12 is pulled up to the preliminary chamber 3, the valve 7 is closed to cut off communication between the introduction section 6 and the preliminary chamber 3, and the connection valve to the exhaust pipe line is closed. Close the sample container holder 1, introduce outside air into the preliminary chamber 3, bring it to atmospheric pressure, and then close the sample container holder 1.
2, a plurality of sample containers 1' containing samples are loaded therein, and the sample container holder 12 is again placed at a predetermined position in the sample introduction section 6 in the same manner as described above.

Then, the operations of introducing and collecting the sample container 1' described above are repeated.

In addition, the sample container 1' stored in this manner in the collection bottle 29 is transferred to the collection bottle 2 by closing the valve 7' at an appropriate time.
9 and the introduction part 6, and outside air is introduced into the recovery bottle 29 through a valve (not shown) to bring the pressure inside the bottle to atmospheric pressure.
All you have to do is remove it from the container and take out the sample container 1' inside.

Although this is not the main idea of this invention, in preparation for analysis and measurement of highly volatile samples, a water cooling pipe is installed in the standby position of the boat 15 in a range that does not impede leftward movement of the boat 15 and fall of the sample container 1'. The boat 15 may be provided with means to constantly cool the boat 15 and prevent the sample contained in the sample container 1' contained therein from vaporizing.

As mentioned above, when introducing, for example, seven sample containers 1' into the ionization chamber 5 one after another, in the conventional apparatus, the vacuum aerodynamic operation, which is a troublesome preparation process, is performed each time the sample containers 1' are introduced one by one. In contrast, in the device of this invention, the operation is performed once each for inserting the sample container holder 12 into a predetermined position and removing it from the outside. It is only necessary to carry out the vacuum airlock operation described above, and the removal of the collection bottle 29 can also be carried out in parallel with any of the vacuum airlock operations described above, so 12 vacuum airlock operations can be omitted. The total number of hours can be reduced by at least 50% because the time required for the preparation process is significantly saved.

Although the embodiment described above is an example in which the device according to this invention is incorporated into a magnetic field type single focus mass spectrometer using a thermionic bombardment type ion source, it goes without saying that it can be used in other mass spectrometers. Moreover, the method of introducing sample containers one by one from a sample container holder loaded with a plurality of sample containers into the heating vaporization section is not limited to the above embodiment, and various methods are possible.

As is clear from the above explanation, the continuous sample introduction device in the mass spectrometer according to this invention is more effective than the conventional device, which requires a tedious preparation process for analysis and measurement of a large number of samples. There is no need to repeat the vacuum air operation required for introducing and removing sample containers into the vacuum chamber for each sample measurement, and it is performed once each when introducing and removing multiple sample containers at the same time. This reduces the time required for the tedious preparation process, which accounts for the total time required for analytical measurements, and reduces the time required for analytical measurements of the entire sample to at least 50% or less. Analytical measurements can be performed extremely efficiently.

In addition, when analyzing and measuring a large number of samples, it is possible to significantly reduce the number of repetitions of vacuum air operation, thereby preventing problems such as trace amounts of oil from the vacuum pump and trace components from the atmosphere being brought into the vacuum chamber and disturbing the measurement background. can be significantly reduced.

[Brief explanation of the drawing]

Figure 1 is a schematic illustration of a conventional sample introduction device in a mass spectrometer, Figure 2 is a schematic illustration of a continuous sample introduction device according to this invention incorporated into a mass spectrometer, and Figure 3 is a sample container holder. sample container storage part of the sample container and the diluent introduction probe (
FIG. 4 is an explanatory view showing the operating state of the main part of the sample container holder. 1.1...Sample container, 3...Preliminary room,
5...Ionization chamber (ion source), 6...
・Sample introduction part, 7, 7'... Valve (circle valve), 7''... Handle, 8... Coiled heater, 12... Sample Container holder, 13.
...Sample container loading operation rod, 14...
Sample introduction probe, 15...Sample container housing part (
boat), 21... support arm, 22...
Box frame, 23... Leaf spring (bottom plate), 24...
・・Push plate spring, 25・・・・Slit, 26・・
...Small leaf spring (support plate), 27...Sample gas introduction cylinder (heating vaporization section), 28, 28'...Seal, 29...Sample container Collection bottle.

Claims (1)

[Scope of utility model registration request] 1. A preliminary chamber that can be evacuated, a vacuum chamber that is airtightly isolated from the preliminary chamber by a valve that can be opened and closed; A sample holder that removably holds multiple sample containers, and a heating vaporization unit that gasifies the sample and introduces it into the ion source from the sample holder one by one by operation from outside the vacuum. and a mechanism for introducing the sample container transferred to the heating vaporization section into the sample collection bottle attached to the vacuum chamber via a separate valve that can be opened and closed. Sample introduction device. 2. The mechanism for transferring samples one by one from the sample holder to the heating vaporization section works in conjunction with the removable bottom plate of the sample holder and the removal operation of this bottom plate, and stacks and loads the samples in the sample holder. A support plate attached to the sample holder that operates to support the second or higher sample container from the bottom, and a support plate attached to the sample holder that operates to support the second or more sample containers from the bottom, and mutually perform the attachment/detachment operation of the bottom plate and the escape/support operation of the support plate. A sample container loading operation rod is slidably engaged with the wall surface of the vacuum chamber in an airtight manner, and a sample is dropped one by one from the lower end of the sample container holder each time the bottom plate is removed. The sample introduction probe has a container accommodating section and is slidably engaged with the wall surface of the vacuum chamber to introduce the sample container accommodated therein into the vaporizing section in the vacuum chamber. A continuous sample introduction device for a mass spectrometer according to claim 1 of the utility model registration claim. 3. The mechanism for introducing the sample container transferred to the heating vaporization section into the sample collection bottle has a sample container accommodating section, and the sample container accommodated therein is transferred from the heating vaporization section in the vacuum chamber to the sample attached to the vacuum chamber. A sample introduction member that is slidably and rotatably engaged with the wall surface of the vacuum chamber in an airtight manner so that the sample container is pulled out directly above the collection bottle and rotated 180 degrees at that position to allow the sample container to fall into and be received by the sample collection bottle. A continuous sample introduction device for a mass spectrometer according to claim 1, which comprises a probe.