JP2949108B1 - Nebulizer array - Google Patents

Abstract

To provide a sonic spray using a sonic gas flow for spraying a liquid devised so that a large amount of liquid can be efficiently vaporized. SOLUTION: A liquid to be vaporized is supplied from a plurality of tubes,
Effluent gas from around the plurality of tubes provides the gas with the required flow rate at the ends of the tubes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atomizer for vaporizing a liquid with high efficiency, and more particularly to an inductively coupled plasma / mass spectrometer (ICP / MS) used for analyzing inorganic and organic substances.
Or microwave induced plasma / mass spectrometer (MIP / M
The present invention relates to a sprayer useful for coating resist or the like on the surface of a substrate used for an analytical device such as an inductively coupled plasma (ICP) emission spectrometer, an atomic absorption spectrometer, or an electronic device.

[0002]

2. Description of the Related Art An inductively coupled plasma-mass spectrometer (IC)
2. Description of the Related Art In analyzers such as a P-MS, a microwave induction plasma-mass spectrometer (MIP-MS), and an inductively coupled plasma (ICP) emission spectrometer, a coaxial spraying a sample liquid onto a plasma region to ionize the sample liquid is performed. One glass-shaped sprayer is used. For example, Spectro Timica Acta, Vol. 49B, paragraphs 901 to 914 (1
994) (SpectrochimicaActa Vol. 49B, pp. 901-91
4, 1994), a glass sprayer is used for spraying a sample liquid. At the end of the spray pipe, the spray gas reduces the pressure to 1 atm or less. Utilizing the pressure difference, the sample liquid is automatically supplied from the container to the nebulizer. The flow rate depends on the gas flow rate, but is usually about 300 μL / min.

Japanese Patent Application Laid-Open No. 8-62200 discloses a proposal of a sonic spray atomizer by the inventors of the present application. In this atomizer, a sonic gas flow is used as the atomizing gas, so that extremely fine ionized droplets can be generated. As a result, the vaporization efficiency of the spray liquid is significantly improved as compared with the conventional glass sprayer. In the sonic spray atomizer, the gas flow rate is fixed to the condition of sonic gas flow generation,
The flow rate of the sample liquid is controlled by a pump.

[0004]

SUMMARY OF THE INVENTION The present invention focuses on the good vaporization efficiency of the spray liquid of the sonic spray atomizer, and proposes to apply the sonic spray atomizer to the above-mentioned analyzer or coating apparatus. . In this case, one problem is that it is not possible to use a sonic spray atomizer with a sufficiently high vaporization efficiency at a sufficient liquid flow rate. This will be described with reference to the analysis results shown in FIG. FIG. 5 shows a microwave induced plasma.
The analysis result when a sonic spray atomizer is attached to the atomizer of the mass spectrometer (MIP-MS) instead of the conventionally used coaxial glass atomizer is shown. In this measurement, a sample liquid containing several types of elements is introduced at various liquid flow rates, and the analysis sensitivity (ionic strength) is measured. The flow rate of the sample liquid is plotted on the horizontal axis, and the ionic strength is plotted on the vertical axis. As shown in FIG. 5, the analysis sensitivity (ion strength) increases as the liquid flow rate increases, but the analysis sensitivity (ion strength) increases.
Is not necessarily proportional to the liquid flow rate. For example, 30μ
At flow rates below L / min, the analytical sensitivity (ionic strength) is approximately proportional to the liquid flow rate, but at flow rates above 30 μL / min,
Increasing the liquid flow rate hardly increases the analytical sensitivity. Particularly at a flow rate of 100 μL / min or more, the analysis sensitivity does not increase at all. Microwave induced plasma
In the nebulizer of the mass spectrometer (MIP-MS), when the vaporization efficiency of the sample liquid by spraying is sufficiently high, the analysis sensitivity (ion intensity) is considered to be proportional to the liquid flow rate. That is, the result of FIG.
This indicates that when using a liquid flow rate as low as μL / min or less, even if a sufficiently high vaporization efficiency is obtained, even if a sample with a flow rate exceeding this is supplied, a sufficiently high vaporization efficiency cannot be obtained. I can say.

[0005] When the sample liquid cannot be sprayed with high vaporization efficiency, not only the improvement of the analysis sensitivity (ionic strength) cannot be expected, but also a large amount of the sample liquid becomes large liquid droplets, which contaminates the analyzer.

However, the sonic spray nebulizer is ideally used at a liquid flow rate of about 30 μL / min. However, even if it is used at a rate of about 100 μL / min, it is usually about 300 μL / min. In view of the liquid flow rate, it can be said that the sonic spray atomizer alone has insufficient capacity in terms of the liquid flow rate.

[0007]

The above object can be attained by preparing a plurality of sonic spray atomizers and spraying a high flow rate of liquid with high vaporization efficiency. In the analyzer, gas generated by the nebulizer is introduced into a spatially narrow region such as a plasma or an analysis unit through a tube. Therefore, sonic spray nebulizers are arranged in an array, and individual sonic spray nebulizers are used at a flow rate at which high vaporization efficiency can be obtained, and a sufficient number of sample solutions are supplied by the number of nebulizers.

In order to make use of the fact that a plurality of sprayers are provided to increase the throughput of the analyzer, a valve capable of independently opening and closing the flow path for each sprayer and controlling the valve in accordance with the result of the analyzer. Means are provided.

[0009]

FIG. 1 is a schematic view showing the configuration of an embodiment of a sprayer array according to the present invention in the form of a perspective view, and FIG.
It is a schematic diagram which shows the cross-section when this is cut | disconnected in the vertical direction. Reference numeral 4 denotes a sprayer array housing, and orifice openings 5 are arranged at predetermined intervals on a front plate 9 provided on the front surface. At the center of each orifice opening 5, a nozzle opening 2 'of the pipe 2 is opened. A gas chamber 10 is formed between the main body of the atomizer array housing 4 and the front plate 9, and a gas having a predetermined pressure is supplied to the gas chamber 10 through a gas inlet 3 by a gas supply unit (not shown). Supplied. The plurality of pipes 2 are integrated by a distributor 6, and the sample liquid introduced from the introduction path 1 is distributed. The pipe 2 is inserted through a through-hole in the main body of the atomizer array housing 4 and held as shown in FIG. 2, but it is held at a predetermined strength at this part and gas leakage does not occur. Retained in the structure. It is natural that the front plate 9 has a structure that can maintain a predetermined strength even when attached to the front surface of the main body of the sprayer array housing 4. When the cross-sectional area of the flow passage 1 is substantially equal to the sum of the cross-sectional areas of the tubes 2, the liquid can be introduced into the flow passage 1 at a low pressure. The orifice openings 5 and the nozzle openings 2 'of the pipe 2 have the same size and the same shape.

The gas introduced into the gas chamber 10 is ejected from the orifice opening 5 to the outside, and the liquid introduced into the pipe 2 is sprayed from the nozzle opening 2 'by the gas flow. When the difference between the pressure in the gas chamber 10 and the atmospheric pressure is approximately 1 to 3 atm, good vaporization efficiency can be obtained.

The nebulizer array of the present invention can be applied to various analyzers. For example, solutions separated by liquid separation means such as liquid chromatography and capillary electrophoresis are introduced into the nebulizer array in time series. In this case, it is necessary that the lengths of the tubes 2 are almost the same. When a simple trial calculation is performed using an electrophoresis apparatus using a capillary having a length of about 50 cm, it is desirable that the variation in the length of each tube 2 is about 0.1 mm or less. In this case, since the bending of the tube 2 is not a problem, any structure can be adopted. However, arranging the orifice openings 5 on the same circumference is useful for making the length of the tube 2 uniform.
Also, the tube 2 should be as short as possible in order to minimize the diffusion of separated components during movement through the tube 2.

It is known that the diameter of the droplet generated by spraying depends on the flow rate of the spray gas and is minimized at the speed of sound (Mach 1), and is called a sonic spray. When the liquid is sprayed by the sonic gas flow, a large amount of fine droplets having a diameter of 1 μm or less and having a high vaporization rate are generated. In practice, if the gas flow velocity is in the range of Mach 0.75 to 2, submicron droplets are generated, and high vaporization efficiency of the liquid is obtained. The flow rate of the gas flow depends on the gas pressure in the gas chamber 10 inside the nebulizer housing 4 and is obtained when the gas pressure is 1.8 to 5 times the pressure around the nebulizer array. Therefore, when the nebulizer array is installed under atmospheric pressure, the gas pressure introduced from the gas inlet 3 into the nebulizer housing 4 needs to be 1.8 to 5 atm.
Further, when the thickness of the orifice 5 is sufficiently small, a sonic gas flow is realized at 2 atm, and the vaporization efficiency is the highest.

The vaporization efficiency of the liquid by spraying is higher when the inner diameter of the tube 2 is smaller. However, when the inner diameter is 1 μm or less, there is a high possibility that the tube 2 will be clogged by particles such as dust, causing a problem in practical use. When the inner diameter is 100 μm or more, the liquid vaporization efficiency is reduced. Therefore, in order to obtain high vaporization efficiency of the liquid, the inner diameter of the tube 2 is 1 to 100 μm
Must be within the range. Further, the vaporization efficiency of the liquid by spraying is determined by the wall pressure of the pipe 2 (1/1 / the difference between the outer diameter and the inner diameter)
Depending on 2), the thinner, the higher the vaporization efficiency. However, if the meat pressure is not more than 5 microns, a problem in strength generally occurs, and if the meat pressure is 50 μm or more, the vaporization efficiency is significantly reduced.

FIGS. 3A to 3C show an embodiment of the arrangement of the tube 2 with respect to the orifice opening 5, the structure of the orifice opening, and the structure of the tip of the tube 2 in consideration of the above. .

The tip of the tube 2 is located outside the plate 9 from 0 to 0.
There is no problem if it protrudes about 3 mm, but if it protrudes 1 mm or more, the liquid vaporization efficiency is reduced. Further, there is no problem even if the plate 9 is recessed by about 0.2 mm from the outer surface on the spray side. Focusing on this, FIG. 3A shows an arrangement in which the tip of the tube 2 is arranged on the curved surface shown by the broken line in the figure to converge the spray gas. Such a structure is advantageous in a case where ionization is performed by irradiating the plasma region of the analyzer with a spray gas. Conversely, for applications such as painting, the curved surface can be reversed and sprayed in the direction in which the spray gas is emitted.

Needless to say, it is convenient for manufacturing that the tip of the tube 2 is in a certain plane.

FIG. 3 (b) shows a contrivance designed to prevent a decrease in gas pressure when the thickness of the plate 9 is large. By chamfering the plate 9 on the gas chamber 10 side, only the vicinity of the nozzle opening 2 'is made an orifice opening.

FIG. 3C shows a case where the outer diameter of the tube 2 is large.
This is a device devised to prevent a reduction in gas pressure when the thickness of the plate 9 is equivalently large by scraping around the nozzle opening 2 ′. The orifice opening is formed by chamfering the plate 9 on the gas chamber 10 side.

FIG. 4 is a schematic view showing a cross-sectional structure of a sprayer array according to another embodiment of the present invention intended to increase the throughput of the analyzer. The front part of the nebulizer array is the same as that of the embodiment of FIG. 2 except that a different sample liquid is supplied to each tube 2, a valve 11 that can turn on and off the supply of the sample liquid is provided for each tube, and The difference is that a control device 12 for controlling the opening and closing of the valve according to the result of the analyzer is provided.

The present embodiment is advantageous when it is desired to detect whether a specific substance can be detected from many sample liquids with high throughput. That is, as a first step of the analysis, the valves 12 are all opened to supply these mixed gases from the nebulizer array to the analyzer to analyze whether or not the mixed gases contain a specific substance. If the mixed gas does not contain a specific substance, the analysis may be shifted to the next sample fluid group. On the other hand, if a specific substance is contained in the mixed gas, all of the valves 12 are closed once, and then only one of the valves 12 is sequentially opened, and the gas of the sample fluid with the valve 12 opened from the nebulizer array is opened. Is supplied to an analyzer to analyze whether or not this gas contains a specific substance. In this case, since a specific substance may be contained in a plurality of sample gases, this operation needs to be performed for all sample fluids.

As described above, the sonic spray atomizer used in the present invention cannot supply a sufficient sample solution to the analyzer when used at a flow rate that provides high vaporization efficiency. If it is sufficient to detect whether or not the sample is contained, a sufficient sample solution is not necessarily required. Therefore, if a method for detecting the presence or absence of a specific substance in a sample group is used, the analysis operation can be completed in a single analysis for a sample group in which a specific substance is not detected, so that high throughput can be realized. is there.

In the above-described embodiment, it is desirable that the cross section of the tube 2 is circular. However, even if the cross section is rectangular, sufficient vaporization efficiency can be obtained. When used for an inorganic analyzer or the like, it is necessary that the flow passage 1, the distributor 6, and the pipe 2 be made of a nonmetal such as silicon or quartz. The front plate 9 constituting the orifice opening 5 is preferably made of a non-metal such as quartz or sapphire for use in inorganic analysis, but is generally easily formed on a stainless steel plate by laser light irradiation or the like. Yes, this may be practical. When it is made of sapphire, it is preferable to make it thick as a whole as shown in FIG. The front plate 9 made of a stainless steel plate may be coated with polyimide or the like. With this configuration, the thickness of the stainless steel plate can be about 0.2 mm and the thickness of the polyimide can be about 2 μm, so that the thickness can be made sufficiently thin.

The arrangement of the orifice opening 5 and the end of the pipe 2 in the atomizer array of the present invention can take various forms, but it is necessary to devise a high atomizing gas concentration as a small atomizer array as a whole. good.
Generally speaking, it is preferable to distribute the orifice openings 5 as densely and evenly as possible. However, the closest distance between the adjacent orifice openings 5 is preferably about 2 mm. The reason for this is that, until the liquid drawn out from the nozzle opening 2 ′ of the pipe 2 by the gas is vaporized and gasified, it is possible to obtain higher vaporization efficiency without mutual interference.

[0024]

According to the nebulizer array of the present invention, a large amount of fine liquid droplets are generated by spraying a large amount of liquid with a gas,
Furthermore, gas by their vaporization can be efficiently generated. In addition, high throughput of analysis can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic view showing the configuration of an embodiment of a sprayer array according to the present invention in the form of a perspective view.

FIG. 2 is a schematic diagram showing a cross-sectional structure when the sprayer array shown in FIG. 1 is cut in a vertical direction.

FIG. 3 is a schematic view showing a cross-sectional structure of an embodiment regarding the arrangement of the tube 2 with respect to the orifice opening 5, the structure of the orifice opening, and the structure of the tip of the tube 2.

FIG. 4 is a schematic diagram showing a cross-sectional structure of a sprayer array according to another embodiment of the present invention intended to increase the throughput of the analyzer.

FIG. 5: Microwave induction plasma-mass spectrometer (MI
The figure which shows the analysis result at the time of attaching a sonic spray atomizer instead of the coaxial glass atomizer to the atomizer of (P-MS).

[Explanation of symbols]

1: flow passage, 2: pipe, 2 ': nozzle opening, 3: gas inlet, 4: atomizer array housing body, 5: orifice opening, 6: distributor, 9: atomizer array housing front plate, 10: gas Chamber, 11: Valve control device, 12:
valve.

Continuing from the front page (72) Inventor Yukiko Hirabayashi 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd. (72) Inventor Hideaki Koizumi 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (56) References JP-A-4-188555 (JP, A) JP-A 8-99051 (JP, A) JP-A-9-239298 (JP, A) JP-A-5-96210 (JP, A) JP-A-9-257751 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01N 27/62-27/70 G01N 21/00-21/74 H01J 49/00-49/48 B05B 7/00-9/08

Claims (5)

(57) [Claims] And 1. A distributor for diverting liquids, wherein the distributor Niso
Holds a plurality of tubes with one ends connected and the other end of the tubes
Housing with a gas chamber formed inside the body
And the housing guides gas to the gas chamber.
Gas from the inlet and the other end of the pipe.
And a front plate having a plurality of openings to be ejected. 2. The sprayer array according to claim 1, wherein said plurality of tubes have the same cross-sectional shape. 3. A sprayer array according to claim 1, wherein the distance between the tips of the other ends of the tubes closest to each other is substantially equal. 4. The nebulizer array according to claim 1, wherein the end surfaces of the other ends of the plurality of tubes are arranged on a plane or a curved surface. 5. The sprayer array according to claim 1, wherein the lengths from the distributor of the plurality of tubes to the tip of the other end of the tubes are substantially the same.