JP2623179B2 - Sample vaporization analysis method using mass spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, and the sample of the sample
A ferromagnetic metal body having a thermal decomposition temperature as a Curie point is brought into contact with a sample cell, and the metal body is instantaneously heated to the Curie point by high-frequency induction heating, and the sample in contact with the metal body is heated.
The present invention relates to an analysis method for decomposing and analyzing volatile gas generated from a sample by thermal decomposition with a mass spectrometer.

[0002]

2. Description of the Related Art Conventionally, to vaporize and analyze a sample with a mass spectrometer, a resistance heater is provided on the inner periphery of a hollow stainless steel rod inserted through a O-ring into a vacuum ionization chamber. A sample contained in a quartz sample cell held in an extended shape at the tip of a stainless steel rod is vaporized by indirect heating with the above-described resistance heater, and analyzed by a mass spectrometer.

[0003]

In the above conventional example, the usable set temperature is generally 350 ° C. due to the restriction on the performance of the resistance heater as the heating source, and even if the special specification is used, the set temperature is 50 ° C.
0 ° C is the upper limit. In addition, the temperature sensor is mounted near the heater, while the sample is indirectly heated through the stainless steel rod and the sample cell, so it is difficult to reach the indicated temperature, and the temperature of the sample is actually heated many times. I can't tell if they are . Further, the temperature rise of the sample is also indirect heating a is for time or Ri, since samples before reaching the target temperature continuously volatilized, is possible to generate a pulsed manner ions <br/> down No, the sensitivity in the mass spectrometer is low, and the peak is not clear . Furthermore, since the hollow stainless steel rod with a built-in resistance heater penetrates the O-ring for maintaining the vacuum of the ionization chamber, the temperature of the stainless steel rod is set to the heat-resistant temperature of the O-ring (usually 200 ° C.).
Only after waiting for the temperature to drop below, the stainless rod can not be pulled out of the ionization chamber through the O-ring . Therefore, put the next new sample in the sample cell
Ru or time to analysis.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a method for vaporizing and analyzing a sample using a mass spectrometer developed to solve the above-mentioned problems. The sample and the pyrolysis of this sample
A sample cell held in contact with a ferromagnetic metal body having a Curie point at temperature is held, and the high-frequency heating coil and the sample cell held on the inner periphery of the bobbin are ionized by a mass spectrometer. The ferromagnetic metal body in the sample cell is instantaneously heated to the Curie point by energizing the high-frequency heating coil, thereby thermally decomposing the sample in contact with the metal body.
Then , the volatile gas is ionized by an electron beam generated in the ionization chamber to obtain a mass spectrum.

That is, the present invention resides in a ferromagnetic metal body.
Utilizing heating by friction of minute magnetic domains (domains)
So energize the high-frequency heating coil to heat the ferromagnetic metal body
When the heating temperature of the metal body reaches the Curie point,
Each domain breaks apart and loses ferromagnetism, and at the Curie point
Focusing on high self-controllability with stable temperature,
For example, if the sample is polystyrene resin, its thermal decomposition temperature
Is 434 ° C., and in this case, the metal composition is Fe50
%, In the Ni50%, ferromagnetic metal of the Curie point of 434 ℃
The body is used in contact with polystyrene resin in the sample cell
When the sample is ABS resin, its thermal decomposition temperature is 5
Because it is 90 ° C, the metal composition is 87% Ni and 13% Co,
A ferromagnetic metal with a Curie point of 590 ° C was tested with ABS resin.
When the sample is nylon resin
In this case, the thermal decomposition temperature is 670 ℃, so in this case the metal composition
Is Cr 17%, Ni 7%, Fe 76%, and the Curie point is
A ferromagnetic metal at 670 ° C is mixed with nylon resin in a sample cell.
Use by contacting, energize high frequency heating coil and ferromagnetic
Instantly heat the metal body to the Curie point in about 0.2 seconds and try
Sample that is made by thermal decomposition of the material
Of the volatile gas is ionized by the electron beam in the ionization chamber,
By obtaining a mass spectrum,
The problem was solved .

[0006]

FIG. 1 is a sectional view showing a state in which a sample cell and a high-frequency heating coil of a measuring section are inserted into an ionization chamber of a mass spectrometer, FIG. 2 is an enlarged sectional view of the above measurement, and FIG. FIG. 3 is an exploded perspective view of FIG.

The measuring section includes a ceramic cylindrical bobbin 2 having a high-frequency heating coil 1 wound around one end thereof, and a quartz sample cell 3 held through the inner periphery of the bobbin 2. The sample cell 3 has a sample storage section 4 as a blind hole opened at one end, and the high-frequency heating coil 1 surrounds the outside of the storage section 4 and induces a ferromagnetic metal body placed in the storage section 4 by high-frequency induction. for the purpose of heating up to the Curie point instantly heating
There is .

Reference numeral 5 denotes a brass cylindrical electrode which has a female-threaded large-diameter portion into which the male screw 2 'at the other end of the cylindrical bobbin 2 is screwed, and a sample cell 3 which penetrates the cylindrical bobbin. Having at one end a cylindrical portion 6 having a small diameter portion with which the end fits,
It has a male screw cylinder 7 at the other end. A semi-circular tube 8 connected to the male screw tube 7 and a semi-circular portion 9 connected to the cylindrical portion 6 are provided between the cylindrical portion 6 and the male screw tube 7. The open surface of the semicircular cylinder 8 and the diameter plane 9 'of the semicircle portion 9 are in the same plane, and one lead wire 1a of the high-frequency heating coil 1 is fixed on the diameter plane 9' by a set screw 10. It is.

The sample cell 3 has a flange 3 'at one end. When the sample cell 3 is inserted from one end into the inner periphery of the cylindrical bobbin 2 until the flange 3' comes into contact with one end of the cylindrical bobbin 1, the sample cell 3 Is protruded from the other end of the cylindrical bobbin by a predetermined length.

The cylindrical portion 6 at one end of the cylindrical electrode 5 is provided with an O-ring 12 in advance so as to abut against a step 11 at the boundary between the large-diameter portion with a female thread and the large-diameter portion with a female thread and the small-diameter portion.
Is inserted, and the male screw 2 'at the other end of the cylindrical bobbin is lightly screwed into the large-diameter portion with a female thread of the cylindrical portion 6 and placed. Then, as described above, the sample cell 3 is inserted from one end to the inner periphery of the bobbin until the flange 3 'abuts on one end of the cylindrical bobbin 2, and the other end of the sample cell protruding from the other end of the bobbin is removed. Then, the cylindrical bobbin 2 is strongly screwed into the large-diameter portion with a female thread. As a result, the O-ring 12 is compressed against the step 11 at the other end of the cylindrical bobbin 2 and tightens around the other end of the sample cell protruding from the other end of the bobbin, so that the sample cell is removed from the cylindrical bobbin. To prevent it from exiting. The other end of the sample cell protruding from the other end of the cylindrical bobbin with respect to the other end than the portion fastened by the O-ring is fitted to the inner periphery of the small diameter portion of the cylindrical portion 6.

Reference numeral 13 denotes a columnar electrode to which the other lead wire 1b of the high-frequency heating coil 1 is attached, and a thick shaft portion 15 at one end having a flat portion for fixing the lead wire 1b with a push screw 14.
And a thin shaft portion 16 protruding from the thick shaft portion. Reference numeral 17 denotes a cylindrical insulator made of ethylene trifluoride or the like in which the thin shaft portion 16 penetrates the inner periphery, and has a large diameter provided at one end with an end surface in contact with the other end surface of the thick shaft portion 15 of the electrode 13. The large-diameter cylindrical portion 1 includes a cylindrical portion 18 and a small-diameter cylindrical portion 19 protruding from the large-diameter cylindrical portion.
An annular step 20 is formed on the outer periphery of 8 by a small-diameter portion at one end and a large-diameter portion at the other end. Reference numeral 21 denotes a brass cylindrical adapter. A partition wall 22 having a hole through which the small-diameter cylindrical portion 19 of the cylindrical insulator 17 penetrates is provided in the middle of the inside, and an inner periphery on one end side of the partition wall is provided on the inner periphery. Large-diameter cylindrical portion 18 of cylindrical insulator
There is a female screw 23 into which the large-diameter portion of the outer periphery fits and into which the male screw cylinder 7 of the cylindrical electrode 5 is screwed.

An O-ring 24 is applied to the end surface of the large-diameter cylindrical portion 18 of the cylindrical insulator 17, and the thin shaft portion 16 of the electrode 13 is inserted into the hollow portion of the cylindrical insulator from one end. The outer male screw 25 is screwed into the inner female screw of the small-diameter cylindrical portion 19 of the cylindrical insulator, and the O-ring 24 is compressed to the end surface of the large-diameter cylindrical portion 18 at the other end surface of the thick shaft portion 15 of the electrode. Sealing is performed, and the other end of the thin shaft portion 16 of the electrode is projected from the other end of the small-diameter cylindrical portion 19. Further, an O-ring 26 and a cylindrical insulator 17 are fitted inside one end of the cylindrical adapter 21, and the small-diameter cylindrical portion 19 of the cylindrical insulator through which the thin shaft portion 16 of the electrode penetrates is formed into a hole in the partition wall 22. And apply the O-ring 26 to the partition wall 22. Then, the male screw cylinder 7 of the cylindrical electrode 5 is screwed into the female screw 23 inside one end of the cylindrical adapter 21 and tightened, so that the distal end of the male screw cylinder 7 is on the outer periphery of the large-diameter cylindrical portion 18 of the cylindrical insulator. Pressing the step 20, compressing the O-ring 26 against the partition wall 22 at the other end surface of the large-diameter cylindrical portion 18,
Seal.

Thus, the electrode 13, the high-frequency heating coil 1, and the cylindrical electrode 5 to which the sample cell 3 is attached are assembled to the cylindrical adapter 21 via the cylindrical insulator 17. The cylindrical adapter 21 is screwed or welded to the inner periphery of one end of the pipe 27 with a male screw at the other end, and is attached to the electrode 13 from the other end of the small-diameter cylindrical portion 19 of the cylindrical insulator. The protruding thin shaft portion 16 faces an electrode 28 which is insulated and concentrically attached to the other end of the pipe 27.

A cylindrical electrode 5, a cylindrical adapter 21, a pipe 2
Since the electrode 7 is electrically conductive, the electrodes 13 and 28 are connected to each other by the electric wire 29 and the high-frequency heating coil 1 is energized (for example, 4 MHz), so that the sample 4 is stored in the accommodating section 4 of the sample cell 3.
The ferromagnetic metal material put in contact with the sample
Is instantaneously heated to the Curie point of the thermal decomposition temperature , and the sample in contact with the metal body is volatilized by the thermal decomposition and gasified.

In order to perform the analysis, after preliminarily exhausting the ionization chamber 30 of the mass spectrometer, the ionization chamber 30 is inserted through the O-ring 31 into the ionization chamber 30 with the high-frequency heating coil 2 and the sample cell 3 at the head. After the interior of the chamber is evacuated, the high-frequency heating coil 1 is energized as described above, and the ion source 32 of the mass spectrometer is energized to thermally decompose into an electron beam 33 irradiated from the ion source 32.
The volatile gas of the sample is ejected, and the sample is
The volatile gas is ionized to obtain a mass spectrum, which is introduced into an analysis system for analysis.

In the case of a sample having a high boiling point such as a higher fatty acid and having a low decomposition temperature, a derivative thereof is conventionally produced to lower the boiling point and subjected to analysis. , The above high boiling point sample (pyrolysis temperature 500
C.) and a reaction reagent, for example, a methylating agent (4-methylhydroxyammonium), is brought into contact with a ferromagnetic metal body having a Curie point of 500 ° C., and is put into the container 4 of the sample cell.
analyse. As a result, when the ferromagnetic metal material is instantaneously heated to the Curie point by the high-frequency heating coil 1, methylation and volatilization of the sample proceed simultaneously, and the gas is ejected to the electron beam 33 in the ionization chamber, ionized and mass-spectrometered. It is introduced into the analysis system of the meter and the analysis is performed. Thus,
A sample that can be easily decomposed and hardly volatilized, but can produce a derivative that is easily volatilized by the added reaction reagent, for example, a higher fatty acid can be introduced into the mass spectrometer in one step without converting the derivative into a derivative.

In the embodiment in which the sample and the reagent are brought into contact with the ferromagnetic metal body, when the ferromagnetic metal body is a foil, a sample 35 is placed on the foil 34 as shown in FIG. The required amount may be dropped on the sample 35, and the foil 34 may be folded in two to sandwich the sample and the reaction reagent therebetween, or the sample and the reaction reagent may be wrapped by the foil 34 and placed in the storage section of the sample cell. . When the ferromagnetic metal body is a wire, the liquefied sample and the reaction reagent may be applied to the metal wire, or the ferromagnetic metal wire 37 may be folded back as shown in FIG. The sample may be wrapped around the sample and the reaction reagent may be dropped.

Further, when a sample having a low boiling point is brought into contact with a ferromagnetic metal body and put into a housing portion of a sample cell, and analysis is performed, volatilization may immediately and continuously start due to the vacuum in the ionization chamber. Decrease. In this case, raised to be adsorbed, for example, 350 ° C. boiling adsorbent samples, the adsorbent containing the sample into contact with the ferromagnetic metal material of the Curie point 35 0 ° C. was placed in the housing portion of the sample cell, high-frequency heating Ferromagnetic gold in coil
The sample is quickly heated by induction heating to the Curie point.
As compared with the case of instantaneous volatilization and continuous volatilization, the concentration of volatile gas per unit time can be increased, and the sensitivity can be increased 10 times or more.

In this case, when the sample and the adsorbent are brought into contact with the ferromagnetic metal body, when the ferromagnetic metal body is a foil, an adsorbent 38 is placed on the foil 34 as shown in FIG. A required amount of the sample solution is dropped on the syringe 36, and the foil is folded in two to sandwich the sample and the adsorbent between them, or the foil and the sample and the adsorbent are wrapped and put into the container of the sample cell. I just need.
When the ferromagnetic metal body is a wire, a liquid sample and an adsorbent may be applied to the metal wire, or the ferromagnetic metal wire 37 may be bent in a folded shape as shown in FIG. May be wrapped with an adsorbent, and the sample liquid may be dropped.

[0020]

According to the present invention , the sample is heated by the heat of the sample.
Contact with a ferromagnetic metal body whose decomposition temperature is the Curie point ,
For heating the ferromagnetic metallic member by high frequency induction heating instantaneously <br/> until the Curie point, the easily decomposable but less volatile sample, or easily evaporate in the reaction with the reaction reagent, continuously in a vacuum the sample to be volatilized adsorbed by the adsorbent, the pulse volatilized gases
And a mass spectrum can be obtained. or,
The thermal decomposition temperature of the sample depends on the type of sample,
Ferromagnetic metal with Curie point as the thermal decomposition temperature of the sample
And contact the sample with the ferromagnetic metal
The sample is instantaneously heated by induction heating the ferromagnetic metal body.
Decomposes sometimes and optimally to the highest concentration in a pulse
Generate high volatile gas and increase the sensitivity of mass spectrum
Analysis in a very short time
Can be .

Further, what is heated is a ferromagnetic metal body,
Since only the sample that has come into contact therewith does not raise the temperature of the portion that comes into contact with the O-ring 31 in the ionization chamber, the next new sample can be prepared immediately after the analysis , and the next analysis can be performed.
Can be started quickly .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an analysis state in which a sample cell and a high-frequency heating coil of a measurement unit are inserted into an ionization chamber of a mass spectrometer.

FIG. 2 is an enlarged cross-sectional view of a measurement unit of FIG.

FIG. 3 is an exploded perspective view of a main part of the measuring unit of FIG.

FIG. 4 is an explanatory diagram of a state in which a sample and a reaction reagent are brought into contact with a ferromagnetic metal foil.

FIG. 5 is an explanatory diagram of a state in which a sample and an adsorbent are brought into contact with a ferromagnetic metal foil.

FIG. 6 is an explanatory diagram of a state where a sample and an adsorbent are sandwiched between ferromagnetic metal wires.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 high-frequency heating coil 2 bobbin of high-frequency heating coil 3 sample cell 4 sample container 30 ionization chamber 32 ion source 33 electron beam 34 ferromagnetic metal foil 35 sample 37 ferromagnetic metal wire

Claims (1)

(57) [Claims] 1. A sample and a thermal decomposition temperature of the sample are set on the inner periphery of a bobbin around which a high-frequency heating coil is wound outside.
Holding the sample cell was charged by contacting the ferromagnetic metal material to a high-frequency heating coil, insert the sample cell held the inner periphery of the bobbin in the ionization chamber of the mass spectrometer, the high-frequency heating coil Current, the ferromagnetic metal in the sample cell is instantaneously heated to the Curie point, thereby thermally decomposing and volatilizing the sample in contact with the metal, and generating the volatile gas in the ionization chamber. A method for vaporizing and analyzing a sample using a mass spectrometer, wherein a mass spectrum is obtained by ionization with a beam.