JPH0731494Y2 - High frequency inductively coupled plasma mass spectrometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a high frequency inductively coupled plasma mass spectrometer with an improved cooling method for a spray chamber, which is one of sample introduction systems.

<Prior art> A high frequency inductively coupled plasma mass spectrometer excites a sample using high frequency inductively coupled plasma, and guides the generated ions to a mass spectrometer through an interface consisting of a nozzle and a skimmer for electrical detection. By precisely measuring the amount of ions, the element to be measured in the sample is analyzed with high accuracy. The spray chamber, which is one of the sample introduction systems, is cooled because only uniform particles are introduced as a sample into the plasma torch 1. Figure 3 shows
It is a conventional example structure explanatory view of such a high frequency inductively coupled plasma mass spectrometer. In this figure, a plasma torch 1
The outer chamber 1b and the outermost chamber 1c are supplied with argon gas from an argon gas supply source 3 via a gas regulator 2. Further, the sample in the sample tank 4 is atomized by the nebulizer 4 ', and then is transported into the spray chamber 5 (specifically, the glass spray chamber body 5a) by argon gas. Here, both sides of the spray chamber body 5a are covered with cooling aluminum blocks 5b and 5c, and the cooling aluminum block 5c and the heat dissipation aluminum block are covered.
A Peltier element 5d is mounted between 5e. Therefore, the sample carried into the spray chamber body 5a is cooled in the spray chamber body 5a by the cooling effect of the Peltier element 5d. In addition, the sample cooled in this way is sprayed again with the argon gas into the spray chamber 5 (specifically, the spray chamber main body).
It is carried into the inner chamber 1a of the plasma torch 1 through the outlet of 5a). On the other hand, a high frequency current is applied to the wound high frequency induction coil 6 of the plasma torch 1 by a high frequency power source 10, and a high frequency magnetic field (not shown) is formed around the coil 6. In this state, when electrons or ions are implanted in the argon gas in the vicinity of the high frequency magnetic field, high frequency inductively coupled plasma 7 is instantaneously generated by the action of the high frequency magnetic field. Further, the inside of the fore chamber main body 11 sandwiched between the nozzle 8 and the skimmer 9 is, for example, 1T by the vacuum pump 12.
being sucked by orr. Further, in the center chamber 13, a small disc 14a for preventing light from entering on the central axis and an ion lens 14b arranged so as to keep a constant distance from the small disc,
14c is provided, and the inside of the center chamber 13 is sucked by the first oil diffusion pump 15 to, for example, 10 ⁻⁴ Torr.
The second oil diffusion pump is inside the rear chamber 17 that houses the
Aspirated by, for example, 10 ^-5 Torr. Ions in the plasma 7 pass through the nozzle 8 and the skimmer 9, and then pass through the mass filter 16 after being converged between, for example, the small disk 14a and the ion lenses 14b and 14c (or the doublet quadrupole lens). The elemental analysis value in the sample is obtained by being guided to the secondary electron multiplier 19 and detected, and the detection signal is sent to the signal processing unit 20 to be calculated and processed. .

<Problems to be Solved by the Invention> However, in the above-mentioned conventional example, when the sample is cooled using the glass spray chamber 5a as described above, the radiating side of the Peltier element is cooled and the cooling side (surface)
There was a drawback that it did not get cold enough. Further, since the spray chamber main body 5a is made of glass as described above, it is difficult to perform processing such that the cooling aluminum block is brought into close contact with the spray chamber main body 5a and the cooling aluminum blocks 5b and 5c, and thus a gap is easily formed. There is also a drawback that the chamber body 5a cannot be cooled sufficiently. The present invention has been made in view of the drawbacks of the conventional example, and an object thereof is to improve the cooling method of the spray chamber and to allow the sample atomized by the nebulizer to pass through the sufficiently cooled spray chamber 5 to form uniform fine particles. The purpose of the present invention is to provide a high-frequency inductively coupled plasma mass spectrometer which is introduced as a sample into the inner chamber 1a of the plasma torch 1 and can ultimately accurately measure the element to be measured.

<Means for Solving Problems> In order to achieve such an object, the present invention is to cool a sample atomized by a nebulizer in a spray chamber, and then guide the plasma torch to excite the sample to be measured. In a high frequency inductively coupled plasma mass spectrometer for mass spectrometric analysis of a sample in a mass spectrometer, the spray chamber comprises a spray chamber body for cooling the sample supplied from the nebulizer to obtain a sample composed of uniform particles, and the spray chamber. A heat transfer silicon sheet provided with one surface in close contact with the main body, an aluminum block for cooling provided with one surface in close contact with the other surface of the heat transfer silicon sheet, and a cooling source. A Peltier element provided so that the cooling surface is in contact with the other surface of the cooling aluminum block. A heat-dissipating surface opposite to the heat-dissipating surface of the element, and a heat-dissipating aluminum block that cools the Peltier element, and the efficiency of cooling the spray chamber body is increased by interposing the heat-transfer silicon sheet Is characterized by.

<Example> Hereinafter, the present invention will be described in detail with reference to the drawings. First
FIG. 2 is an exploded perspective view of a spray chamber showing an essential part of the present invention, and FIG. 2 is an explanatory view of the configuration of an embodiment of the present invention. Further, in these figures, the same symbols as those in FIG. 3 are used with the same meanings, and duplicate explanations are omitted here.
Further, 5'is a spray chamber, 5f and g are mounted between the spray chamber main body 5a and the cooling aluminum blocks 5b and 5c, respectively, and are heat transfer silicon sheets fixed by, for example, an adhesive, and 5i is a cooling water. Through hole, 5j is first
Screws to assemble and secure the components shown, 5h
Is an aluminum block for heat dissipation, which has a communication hole through which cooling water flows. It should be noted that the present invention is not limited to the above-described configuration, and various modifications can be made. For example, a large heat sink may be provided instead of the heat radiating aluminum block. Also, heat transfer silicon sheet 5
A thin lead plate may be sandwiched in place of g and 5f to improve heat conduction.

In the embodiment of the present invention having such a configuration, when a current is applied to the Peltier element 5d, the cooling surface (upper side in FIG. 2) of the Peltier element 5d is cooled and the aluminum block for cooling is in contact with the cooling surface. 5c is cooled. Further, the cooling surface (upper side in FIG. 2) of the Peltier element 5d is cooled, and at the same time, the heat radiating surface (lower side in FIG. 2) of the Peltier element 5d becomes hot, and the heat radiating aluminum block 5h comes into contact with the heat radiating surface. Therefore, the heat load on the Peltier element 5d is reduced, and the cooling aluminum block 5c is further cooled. In this way, the cooling aluminum block 5c is sufficiently cooled, the heat transfer silicon sheet 5g in contact with the cooling aluminum block 5c is cooled, and finally the spray chamber body 5a is cooled. On the other hand, argon gas is supplied from the argon gas supply source 3 to the outer chamber 1b and the outermost chamber 1c of the plasma torch 1 via the gas regulator 2. In addition, the sample in the sample tank 4 is atomized by the nebulizer 4 ', and then is sprayed with the argon gas.
(Specifically, it is transported into the glass spray chamber main body 5a) and cooled in the spray chamber main body 5a by the cooling effect of the Peltier element 5d as described above. The sample cooled in this way is again carried into the inner chamber 1a of the plasma torch 1 through the outlet of the spray chamber 5 (specifically, the spray chamber body 5a) by argon gas. A high-frequency current is applied to the high-frequency induction coil 6 wound around the plasma torch 1 by a high-frequency power source 10, and a high-frequency magnetic field (not shown) is formed around the coil 6. In this state, when electrons or ions are implanted in the argon gas in the vicinity of the high frequency magnetic field, high frequency inductively coupled plasma 7 is instantaneously generated by the action of the high frequency magnetic field. Further, the inside of the fore chamber main body 11 sandwiched between the nozzle 8 and the skimmer 9 is a vacuum pump.
Aspirated by 12 to 1 Torr. Further, in the center chamber 13, there are provided a small disk 14a for blocking the entrance of light on the central axis and ion lenses 14b, 14c arranged so as to maintain a constant distance from the small disk, and the center chamber 13 The inside of 13 is sucked to, for example, 10 ⁻⁴ Torr. By the first oil diffusion pump 15, and the inside of the rear chamber 17 housing the mass filter (eg, quadrupole mass filter) 16 is, for example, by the second oil diffusion pump 18. Aspirated at 10 ^-5 Torr. Ions in the plasma 7 pass through the nozzle 8 and the skimmer 9 and then, for example, the small disk 14a and the ion lens 1
Secondary electron multiplier after passing through the space between 4b and 14c (or doublet quadrupole lens) and then passing through the mass filter 16.
By being guided to 19 and detected, the detected signal is sent to the signal processing section 20 for calculation and processing, whereby the measured elemental analysis value in the sample is obtained.

<Effect of the Invention> According to the embodiment of the present invention as described in detail above, since the heat transfer silicon sheet is provided in close contact between the spray chamber body and the cooling aluminum block,
The heat transfer between the spray chamber body and the aluminum block for cooling is improved, and the spray chamber body can be efficiently cooled by the Peltier element.

Further, since the spray chamber main body is completely covered with the cooling aluminum block via the heat transfer silicon sheet, there is an advantage that heat transmitted to the spray chamber main body by radiation or conduction from the outside can be prevented.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a spray chamber showing an essential part of the present invention, FIG. 2 is a structural explanatory view of an embodiment of the present invention, and FIG. 3 is a structural explanatory view of a conventional example. 1 ... Plasma torch, 3 ... Argon gas supply source, 4
…… Sample tank, 4 ′ …… Nebulizer 5a …… Spray chamber body, 5b, 5c …… Aluminum block for cooling 5d …… Peltier element, 5f, 5g …… Silicon sheet for heat transfer, 5h …… Aluminum block for heat dissipation 5i …… Through hole for cooling water, 5j …… Screw 7 …… High frequency inductively coupled plasma, 8 …… Nozzle, 9 ……
Skimmer, 11 fore chamber, 13 center chamber, 16 mass filter, 17 rear chamber, 20 signal processing unit,

Claims (1)

[Scope of utility model registration request] 1. A nebulizer atomized sample is cooled in a spray chamber and then introduced into a plasma torch for excitation.
In a high frequency inductively coupled plasma mass spectrometer for performing mass analysis of an excited sample to be measured in a mass spectrometer, the spray chamber is a spray chamber body for cooling the sample supplied from the nebulizer to obtain a sample composed of uniform particles. A heat transfer silicon sheet having one surface in close contact with the spray chamber body, and a cooling aluminum block having one surface in close contact with the other surface of the heat transfer silicon sheet, A Peltier element, which is a cooling source and is provided such that the cooling surface is in contact with the other surface of the cooling aluminum block, and a radiating surface opposite to the cooling surface of the Peltier element is contacted to cool the Peltier element. A heat dissipation aluminum block, and the spray chamber is interposed by the heat transfer silicon sheet. A high-frequency inductively coupled plasma mass spectrometer characterized by improving the cooling efficiency of the bar body.