JP2013205389A - Emission analyzer and atomizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emission analyzer capable of analyzing a solid sample by using atmospheric pressure plasma.SOLUTION: The emission analyzer is composed of an atomizer 10 and a spectroscopic analyzer 20. The atomizer 10 includes a rod-like electrode 100 and a blade-shaped electrode 120 arranged separately from a tip part 100a of the rod-like electrode 100 by a fixed distance. The tip part 100a of the rod-like electrode 100 is stored in a ceramic pipe 110 so that axis directions coincide with each other. Discharge gas is allowed to flow into a gap 150 between the rod-like electrode 100 and an inner wall of the ceramic pipe 110 in the tip part 100a side axis direction of the rod-like electrode 100. The blade-shaped electrode 120 has a blade shape and is inserted into a sold sample 30. An insulating plate 130 is arranged between the rod-like electrode 100 and the solid sample 30 in contact with the solid sample 30.

Description

  The present invention relates to a small emission analyzer capable of analyzing a solid sample. In particular, the present invention relates to an emission analysis apparatus using an atomizer that atomizes a sample using atmospheric pressure plasma. And the atomizer.

  As an atomizer for atomizing a sample, an emission analysis apparatus using an atmospheric pressure plasma apparatus is described in Patent Document 1. The atomizer described in Patent Document 1 is a rod-shaped first electrode and a tubular tube, in which the first electrode is held inside, and an insulating tube in which a discharge gas flows between the tube inner wall and the first electrode And a second electrode arranged at a certain distance in the axial direction from the tip of the first electrode. Further, the second electrode is formed in an integrated structure so that the second electrode is exposed on the bottom surface of the sample holder, and the liquid electrode is supplied to the sample holder through the tube.

  Since the emission analysis apparatus described in Patent Document 1 requires only one power source for the atomizer, it can be downsized and portable.

JP2012-13543

  However, the emission analyzer described in Patent Document 1 basically has a structure for use in analyzing a liquid sample. Therefore, in order to analyze a solid sample, it is necessary to devise and labor such as processing the solid sample into a liquid state, and it is difficult to perform a simple analysis. For example, it was difficult to carry out an elemental analysis and quantitative analysis of agricultural products on the spot by bringing an emission analyzer into a farm.

  Therefore, an object of the present invention is to realize a small emission analyzer capable of easily performing elemental analysis and quantitative analysis of a solid sample.

  The invention described in claim 1 includes an atomizer that atomizes a solid sample by atmospheric pressure plasma, and a spectroscopic device that receives light emission of atmospheric pressure plasma including the sample atomized by the atomizer and performs spectral analysis. In the emission analyzer, the atomizer has a rod-shaped first electrode and a tubular shape, and the tip of the first electrode is placed in the tube so that the first electrode is separated from the inner wall of the tube around the axis of the first electrode. The insulating tube through which the discharge gas flows in the axial direction on the distal end side of the first electrode in the gap between the inner wall of the tube and the first electrode, and a blade-like shape inserted into the solid sample The second electrode arranged at a certain distance from the tip of the first electrode, and the solid electrode covered between the first electrode and the second electrode, and a hole was provided in the atmospheric pressure plasma irradiation region Insulating plate, first electrode and second electrode An optical emission spectrometer, characterized in that it has a, an AC power source for applying a voltage to the.

  The shape of the second electrode may be an arbitrary blade shape that can be inserted into the solid sample, and may be a single blade or a double blade. The blade shape has a wedge-shaped cross section (a square with a sharp tip). In particular, in addition to the blade shape, it may be a shape having a protrusion protruding in the direction of the tip of the first electrode. This is because the electric field concentrates on the projecting portion, and atmospheric pressure plasma can be generated more easily.

  Quartz, ceramic, etc. can be used for the material of the insulating plate. The shape of the hole provided in the insulating plate is arbitrary, for example, a cylindrical or prismatic hole. This hole is provided in order to narrow down the irradiation area of the atmospheric pressure plasma to the solid sample and efficiently atomize the solid sample.

  The second electrode and the insulating plate are preferably connected in tweezers at the end. If the second electrode and the insulating plate are integrated into the tweezers in this way, there is no need to position the insulating plate in particular, and the insulating plate is also arranged simultaneously by inserting the second electrode into the solid sample. The emission analysis can be performed more easily.

  As the discharge gas, argon, helium, neon, xenon, oxygen, nitrogen, air, or the like can be used.

  For the material of the first electrode and the second electrode, SUS, copper, tungsten, or the like can be used. However, it is necessary not to use a material containing an element to be analyzed for the second electrode, or to apply a film, plating or the like with a material not containing an element to be analyzed. This is to prevent the second electrode from being atomized and affecting the analysis.

  The tip of the first electrode may have a micro hollow structure. That is, a structure having a cut on the second electrode side of the tip portion may be used. With the micro hollow structure, atmospheric pressure plasma can be generated stably.

  The light receiving position for light emission of atmospheric pressure plasma by the spectroscopic device is such that the direction from the hole in the insulating plate toward the light receiving position is in the range of 15 to 45 ° with respect to the direction from the hole in the insulating plate toward the tip of the first electrode. It is desirable to do. If it is this range, more sufficient light emission intensity can be obtained and the precision of analysis can be improved more. More preferably, the angle is 30 °.

  The invention described in claim 2 is characterized in that, in the invention described in claim 1, the second electrode and the insulating plate are connected in tweezers at the end.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the second electrode has a protrusion that protrudes toward the tip of the first electrode.

  The invention according to claim 4 is an atomizer for atomizing a solid sample by atmospheric pressure plasma, which is a rod-shaped first electrode and a tube, and the tube is formed from the inner wall of the tube around the axis of the first electrode. An insulating tube that holds the tip of the first electrode so that the first electrode is in a separated state, and discharge gas flows in the gap between the tube inner wall and the first electrode in the axial direction on the tip of the first electrode And a blade-like shape, a second electrode arranged at a fixed distance from the tip of the first electrode in a state of being inserted into the solid sample, and disposed between the first electrode and the solid sample. An atomizer comprising: an insulating plate having a hole in an atmospheric pressure plasma irradiation region; and an AC power source for applying a voltage between the first electrode and the second electrode.

  The invention according to claim 5 is the invention according to claim 4, characterized in that the second electrode and the insulating plate are connected in a tweezers shape at the end.

  According to a sixth aspect of the present invention, in the fourth or fifth aspect of the present invention, the second electrode has a protrusion that protrudes toward the tip of the first electrode.

  According to the emission analysis apparatus of the present invention, a small emission analysis apparatus capable of elemental analysis or quantitative analysis of a solid sample can be realized.

  Moreover, according to the atomizer of the present invention, even a solid sample can be easily atomized.

FIG. 3 is a diagram showing the configuration of the emission analyzer of Example 1. The figure which showed the structure of the atomizer. The figure which showed the shape of the blade-shaped electrode 120. FIG. The figure which showed the emission spectrum of Fe. The figure which showed the emission spectrum of Na. The graph which showed the relationship between Ca content and the emitted light intensity of an emission spectrum. The graph which showed the relationship between K content and the emitted light intensity of an emission spectrum. A photograph of a tomato used as a solid sample. The graph which showed the result of having performed the quantitative analysis about each site | part of tomato. The figure which showed the structure of the blade electrode 220 in the emission spectrometer of Example 2. FIG. The figure which showed the structure of the blade-shaped electrode 320 and the insulating board 330 in the emission analysis apparatus of Example 3. FIG.

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  FIG. 1 is a diagram illustrating a configuration of an emission analyzer according to the first embodiment. The emission analyzer is composed of an atomizer 10 and a spectroscopic analyzer 20 as shown in FIG. This emission analyzer irradiates and atomizes the solid sample 30 with the atmospheric pressure plasma by the atomizer 10, receives the light emission of the atmospheric pressure plasma with the spectroscopic analyzer 20, and analyzes the spectrum, thereby analyzing the element of the solid sample 30. And a device for quantitative analysis of target elements.

  FIG. 2 is a diagram showing a more detailed configuration of the atomizer 10. The atomizer 10 includes a rod-shaped electrode 100 (first electrode of the present invention) and a blade-shaped electrode 120 (second electrode of the present invention). The rod-shaped electrode 100 is a rod rod made of Cu having a diameter of 1.2 mm. The blade-like electrode 120 has a long and thin blade-like shape made of SUS (stainless steel), and is viewed from above (the axial direction of the rod-like electrode 100 and the atmospheric pressure plasma irradiation side) as shown in FIG. As shown in FIG. 3B, it is a long and narrow rectangle when viewed from the side.

  For the rod-shaped electrode 100, stainless steel, molybdenum, tungsten, or the like can be used in addition to Cu. For the blade electrode 120, Cu, molybdenum, tungsten, or the like can be used in addition to stainless steel. However, considering that the blade electrode 120 itself is atomized and affects the analysis, the blade electrode 120 is made of a material that does not contain the target element, or is coated or plated with a material that does not contain the target element. Etc. need to be applied.

  The tip end portion 100a of the rod-shaped electrode 100 is accommodated in the tube of the ceramic tube 110 so that the axial directions thereof coincide with each other. The diameter of the tip of the ceramic tube 110 on the blade electrode 120 side is narrowed by one step. The rod-shaped electrode 100 extends to the position of the narrowed tube. A gap 150 is provided between the rod-shaped electrode 100 and the inner wall of the ceramic tube 110. A gap 150 around the axis of the rod-like electrode 100 becomes an Ar gas flow path. Further, the surface of the rod-shaped electrode 100 is covered with an insulating member 170 except for both ends, thereby preventing a short circuit.

  Further, the tip portion 100a of the rod-like electrode 100 has a micro hollow structure. That is, it has a structure having a notch 100b on the edge electrode 120 side of the distal end portion 100a. With such a micro hollow structure, atmospheric pressure plasma can be generated stably and the plasma density can be improved.

  The ceramic tube 110 is connected to the insulating tube 140. The insulating tube 140 has a branch 140a in a direction perpendicular to the axial direction, and the rod-like electrode 100 extending from the tube of the ceramic tube 110 into the tube of the insulating tube 140 is bent and inserted into the tube of the branch 140a of the insulating tube 140. Is exposed to the outside. An insulating material such as a fluororesin can be used for the insulating tube 140.

  Further, a short ceramic tube 160 whose outer diameter substantially matches the inner diameter of the ceramic tube 110 is fitted on the tip end side (the blade electrode 120 side) of the ceramic tube 110. The ceramic tube 160 narrows the atmospheric pressure plasma irradiation range. The tip end portion 100a of the rod-like electrode 100 may or may not extend into the ceramic tube 160.

  The insulating tube 140 is connected to a gas cylinder (not shown) filled with Ar, which is a discharge gas, via a pressure reduction / flow rate controller or the like. Ar gas supplied from the gas cylinder is supplied in the axial direction from the inside of the insulating tube 140 into the tube of the ceramic tube 110, and a gap 150 between the rod-shaped electrode 100 and the inner wall of the ceramic tube 110 passes through the tip of the rod-shaped electrode 100. Ar gas is discharged from the tip of the ceramic tube 160 in the axial direction on the 100a side.

In addition to Ar, He (helium), Ne (neon), Xe (xenon), N ₂ (nitrogen), air, and the like can be used as the discharge gas.

  The blade electrode 120 has an elongated blade shape (see FIG. 3) as described above, and the blade edge side is inserted into the solid sample 30 as shown in FIG. Further, the longitudinal direction of the blade electrode 120 is perpendicular to the axial direction of the rod electrode 100, and the rod electrode 100 and the blade electrode 120 are spaced apart by a certain distance. Further, the blade-like electrode 120 is disposed on the extension line in the axial direction of the rod-like electrode 100.

The insulating plate 130 is a flat plate made of quartz glass. The insulating plate 130 is disposed between the rod-shaped electrode 100 and the solid sample 30, is in contact with the solid sample 30, and covers the solid sample 30. Further, the main surface of the insulating plate 130 is perpendicular to the axial direction of the rod-shaped electrode 100. The insulating plate 130 is provided with a hole 130a. The insulating plate 130 is arranged so that the position of the hole 130 a is on the extension line in the axial direction of the rod-shaped electrode 100. The insulating plate 130 is used to efficiently atomize the solid sample 30 by narrowing the irradiation position of the atmospheric pressure plasma to the position where the hole 130a is opened.

  Note that as the material of the insulating film 130, ceramics or the like can be used in addition to quartz glass. In addition, although the insulating plate 130 is disposed so as to be in contact with the solid sample 30, it is not always necessary to be in contact therewith. The shape of the hole 130a is arbitrary as long as it is a shape penetrating the insulating plate 130, such as a columnar shape or a prismatic shape.

  The rod-like electrode 100 and the blade-like electrode 120 are connected to a 60 Hz AC power supply 180, and a voltage of several thousand kV is applied. A voltage is applied to the rod-shaped electrode 100 and the blade-shaped electrode 120 while flowing Ar gas through the gap 150 between the rod-shaped electrode 100 and the inner wall of the ceramic tube 110 toward the solid sample 30 along the axial direction of the rod-shaped electrode 100. Thus, atmospheric pressure plasma is generated at the tip 100a of the rod-like electrode 100. The atmospheric pressure plasma rides on the gas flow and extends toward the solid sample 30 side. Since the solid sample 30 is covered with the insulating plate 130, only the portion of the solid sample 30 exposed in the hole 130 a opened in the insulating plate 130 is irradiated with atmospheric pressure plasma. As a result, the solid sample 30 is efficiently atomized. A part of the atomized solid sample 30 is mixed with atmospheric pressure plasma to emit light. The emitted light is received by the spectroscopic analyzer 20 and subjected to spectrum analysis, whereby elemental analysis of the solid sample 30 and quantitative analysis of the target element can be performed.

  The above is the detailed configuration of the atomizer 10.

  Next, the configuration of the spectroscopic analyzer 20 will be described. As shown in FIG. 1, the spectroscopic analyzer 20 includes a multi-channel spectroscope 200 and receives light emitted from atmospheric pressure plasma through a condenser lens 210 and an optical fiber 220 to perform spectrum analysis. The light receiving position (the position where light from the atmospheric pressure plasma is incident on the optical fiber 220 after being condensed by the condensing lens 210) is a straight line connecting the hole of the insulating plate 130 and the light incident end of the optical fiber 220. The position is preferably 15 to 45 ° with respect to the straight line connecting the electrode 100. If the light is received at such a position, the emission intensity detected by the multichannel spectrometer 200 is high, and the measurement accuracy can be improved. More desirable is a position at 30 °.

  Since the emission analyzer of the first embodiment described above has a single power source for the atomizer 10, it is small and portable, and it is possible to perform elemental analysis and quantitative analysis on the solid sample 30. Therefore, for example, it is possible to bring an emission analyzer into a farm or the like and perform elemental analysis or quantitative analysis of crops on the spot.

  Next, various experimental results using the emission analyzer of Example 1 will be described.

[Experimental Example 1]
Carrot was used as the solid sample 30, and analysis was performed using the emission analyzer of Example 1. As shown in FIG. 4, the emission spectrum of Fe (iron) at 423 nm could be measured, and as shown in FIG. 5, the emission spectrum of Na (sodium) at 589 nm could be measured. Thus, it was confirmed that the elemental analysis of the solid sample was possible by using the emission analyzer of Example 1.

[Experiment 2]
As the solid sample 30, three standard samples, NIST1515 (Apple Leaves), NIST1547 (Peach Leaves), and NIST1570a (Spinach Leaves) were used, respectively, and the emission spectrum of Ca (calcium) and K were measured using the emission analyzer of Example 1. The emission spectrum of (potassium) was measured. FIG. 6 is a graph showing the relationship between the Ca concentration of each standard sample and the emission intensity of the emission spectrum. FIG. 7 is a graph showing the relationship between the K concentration of each standard sample and the emission intensity of the emission spectrum. As shown in FIGS. 6 and 7, the emission intensity varies linearly according to the Ca concentration and the K concentration, and it can be confirmed that the target element can be quantitatively analyzed by using the emission analyzer of Example 1. It was.

[Experiment 3]
As shown in FIG. 8, tomato is used as a sample, and the pulp part (No. 1) in the vicinity of the skin on the heel side, the pulp part (No. 2) in the center part, the skin part (No. 3), and the vicinity of the middle stage skin. The four parts of the pulp part (No. 4) were subjected to quantitative analysis of the three elements Fe, Ni (nickel) and Na by the emission analyzer of Example 1. FIG. 9 is a graph showing the results. From this graph, it can be seen that differences in components due to differences in tomato parts can be measured.

  In the emission analyzer of Example 2, the blade electrode 120 of the atomizer 10 of Example 1 is replaced with a blade electrode 220 described below.

  FIG. 10 is a diagram showing the shape of the blade-like electrode 220, FIG. 10 (a) is a view from above (the axial direction of the rod-like electrode 100 and the atmospheric pressure plasma irradiation side), and FIG. It is the figure seen from the side. As shown in FIG. 10, the blade electrode 220 has a protruding portion 220 a that protrudes toward the rod-shaped electrode 100. By providing such a protrusion 220a, an electric field can be concentrated on the protrusion 220a, so that atmospheric pressure plasma can be generated more easily.

  The emission analyzer of Example 3 is obtained by replacing the blade electrode 120 and the insulating plate 130 of the atomizer 10 of Example 1 with a blade electrode 320 and an insulating plate 330 described below.

  FIG. 11 is a view of the blade-like electrode 320 and the insulating plate 330 as viewed from the side (direction perpendicular to the axial direction of the rod-like electrode 100). The blade electrode 320 has a configuration in which the end of the blade electrode 120 opposite to the blade is bent and connected to the end of the insulating plate 330. The insulating plate 330 is a plate-shaped member made of quartz glass, like the insulating plate 130, and has a hole 330a. As a whole, as shown in FIG. 11, the blade electrode 320 and the insulating plate 330 have a tweezers-like configuration.

  Thus, by integrating the blade electrode 320 and the insulating plate 330 into a tweezers shape, the insulating plate 330 can also be disposed simultaneously by inserting the blade electrode 320 into the solid sample 30. Therefore, the solid sample 30 can be analyzed more easily.

  It should be noted that the blade-like electrode having the protrusion as in the second embodiment and the insulating plate may be integrated into a tweezers as in the third embodiment.

  Moreover, in Examples 1-3, although the thing of a double blade was used as the blade-shaped electrode 120, you may use the thing of shapes, such as a single blade and a scissors blade. In short, any shape may be used as long as the blade can be inserted into the solid sample 30.

  The emission analyzer of the present invention can be used for analysis of solid samples. In addition, since the emission analyzer of the present invention is small and portable, it is effective for bringing the emission analyzer of the present invention to a farm and performing elemental analysis, quantitative analysis, etc. on the field, for example.

10: atomizer 20: spectroscopic analyzer 30: solid sample 100: rod-shaped electrode 110, 160: ceramic tube 120, 220, 320: blade-shaped electrode 130, 330: insulating plate 140: insulating tube 180: AC power supply

Claims (6)

In an emission analyzer comprising: an atomizer that atomizes a solid sample by atmospheric pressure plasma; and a spectroscopic device that receives and analyzes light emission of atmospheric pressure plasma including the sample atomized by the atomizer,
The atomizer is
A rod-shaped first electrode;
A tip of the first electrode is held in the tube so that the first electrode is separated from the tube inner wall around the axis of the first electrode, and the tube inner wall and the first electrode are held in the tube. An insulating tube through which discharge gas flows in the axial direction on the tip end side of the first electrode,
A second electrode having a blade-like shape and arranged at a certain distance from the tip of the first electrode while being inserted into the solid sample;
An insulating plate disposed between the first electrode and the solid sample and having a hole in the atmospheric pressure plasma irradiation region;
An AC power supply for applying a voltage between the first electrode and the second electrode;
Having
An emission analyzer characterized by that.   The luminescence analyzer according to claim 1, wherein the second electrode and the insulating plate are connected to each other in tweezers at an end portion.   3. The luminescence analyzer according to claim 1, wherein the second electrode has a protrusion that protrudes in a direction toward a tip of the first electrode. An atomizer that atomizes a solid sample by atmospheric pressure plasma,
A rod-shaped first electrode;
A tip of the first electrode is held in the tube so that the first electrode is separated from the tube inner wall around the axis of the first electrode, and the tube inner wall and the first electrode are held in the tube. An insulating tube through which discharge gas flows in the axial direction on the tip end side of the first electrode,
A second electrode having a blade-like shape and arranged at a certain distance from the tip of the first electrode while being inserted into the solid sample;
An insulating plate disposed between the first electrode and the solid sample and having a hole in the atmospheric pressure plasma irradiation region;
An AC power supply for applying a voltage between the first electrode and the second electrode;
The atomizer characterized by having.   The atomizer according to claim 4, wherein the second electrode and the insulating plate are connected to each other in tweezers at an end portion.   6. The atomizer according to claim 4, wherein the second electrode has a protrusion protruding in a direction toward a tip of the first electrode.