Element analysis method and element analyzer

Abstract

To provide an element analysis method which can, in an element analysis where a sample is burned, prevent the sample from being exposed to the atmospheric air before being thrown into a heating furnace, and make highly accurate analysis.SOLUTION: An element analysis method for heating a sample in a heating furnace which is supplied with oxygen, comprises: an encapsulation step of encapsulating a sample in a combustion-assisting container which is formed from a combustion improver, and forming a sample body; a charge step of charging the sample body into the heating furnace; an extraction step of heating the sample body in the heating furnace and extracting a combustion gas generated by combustion of the sample; and an analysis step of analyzing an element contained in the sample on the basis of the combustion gas. A combustion-assisting container 9 comprises a body 91, and a lid 92 which is attached to the body 91. The lid 92 is attached to the body 91 in an inert gas atmosphere, to encapsulated the sample in the combustion-assisting container 9.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an elemental analysis method for heating and burning a sample in a heating furnace supplied with oxygen and analyzing an element contained in the sample by combustion gas generated from the sample.

Background Art

[0002] For example, when quantitatively analyzing elements such as C (carbon) and S (sulfur) contained in a sample such as metal or ceramics, the sample contained in a crucible is burned in a heating furnace under oxygen supply. Then, the combustion gas generated from the sample is analyzed by NDIR (non-dispersive infrared gas analysis method), and elements such as C and S contained in the sample are quantified (see Patent Document 1).

[0003] In such an elemental analyzer in which a sample is burned for elemental analysis, due to structural constraints of the heating furnace and the like, the sample was exposed to the atmosphere until it was weighed and then introduced into the heating furnace.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of the above-described problems, and an object thereof is to provide an elemental analysis method capable of preventing a sample from being exposed to the atmosphere until the sample is introduced into a heating furnace even in elemental analysis for burning the sample, and enabling more accurate analysis.

Means for Solving the Problems

[0006] That is, the elemental analysis method according to the present invention is an elemental analysis method for heating a sample in a heating furnace to which oxygen is supplied, and includes an encapsulation step of encapsulating the sample in a combustion support container formed of a combustion support agent to form a sample body, a charging step of charging the sample body into the heating furnace, an extraction step of heating the sample body in the heating furnace and extracting combustion gas generated by combustion of the sample, and an analysis step of analyzing elements contained in the sample based on the combustion gas. The combustion support container includes a main body and a lid attached to the main body, and the lid is attached to the main body in an inert gas atmosphere so that the sample is encapsulated in the combustion support container.

[0007] If it is such a thing, in the encapsulation step, the sample is encapsulated in the combustion support container in an inert gas atmosphere, so that a state of non-exposure to the atmosphere can be realized until it is charged into the heating furnace. Further, since the combustion support container itself is formed of a combustion support agent, even if the sample body is directly put into the heating furnace and heated, the combustion support container only promotes the combustion of the sample and does not interfere with the elemental analysis of the sample. Therefore, it is possible to realize non-exposure of the sample to the atmosphere and quantitatively analyze the elements contained in the sample with higher accuracy than before.

[0008] For example, in order to simplify the encapsulation operation so that the sample can be encapsulated in the combustion support container in an inert gas atmosphere without using special equipment, it is sufficient that the combustion support container further has a fitting structure or a screwing structure formed between the main body and the lid. If it is such a thing, even when an inert gas atmosphere is realized, for example, in a glove box and it is difficult to include equipment for encapsulation inside, the sample can be easily encapsulated in the combustion support container manually.

[0009] Examples of the combustion support container suitable for promoting the combustion of the sample in the heating furnace include those in which the combustion support container is formed of at least one element selected from the group consisting of W (tungsten), Sn (tin), Cu (copper), Fe (iron), and Ni (nickel).

[0010] Just by putting the sample body into the heating furnace, in order to obtain the effect of a combustion aid composed of multiple types of elements and enable simpler and more appropriate elemental analysis with combustion gas, it is sufficient that the combustion aid container is formed of elements different from the main body and the lid respectively.

[0011] Just by putting the sample body into the heating furnace so that an appropriate amount of combustion aid corresponding to the amount of the sample is provided, in order to make more precise elemental analysis easier to perform, it is sufficient that a plurality of types of combustion aid containers with different sizes are prepared in advance.

[0012] In order not to expose the sample to the atmosphere before it is put into the heating furnace without preparing very advanced equipment, it is sufficient that the encapsulation step is performed inside a glove box filled with an inert gas inside.

[0013] If the weighing of the sample is performed inside the glove box, the sample can be encapsulated in the combustion aid container with almost no change from the weighed mass, and more precise elemental analysis becomes possible.

[0014] For example, even if it takes a long time from when the sample body is formed until it is put into the heating furnace, as in the case where a user without an elemental analyzer requests elemental analysis from others, in order to make the sample or the combustion aid container less affected by the atmosphere and ensure the accuracy of elemental analysis, it is sufficient that it further includes an airtight transfer step of accommodating the sample body in a container and transporting it to the heating furnace in an inert gas atmosphere.

[0015] As a specific embodiment for easily performing the airtight transfer step, an example is that the container is a vial.

[0016] For example, in order to perform elemental analysis almost completely automatically without exposing the sample to the atmosphere, an elemental analyzer that heats the sample in a heating furnace supplied with oxygen, comprising: an encapsulator that encapsulates the sample in a combustion container formed of a combustion aid to form a sample body; an introducer that introduces the sample body into the heating furnace; an extraction mechanism that heats the sample body in the heating furnace and extracts combustion gas generated when the sample burns; and an analyzer that analyzes elements contained in the sample based on the combustion gas, wherein the combustion container comprises a main body and a lid attached to the main body, and the encapsulator is configured to attach the lid to the main body in an inert gas atmosphere to encapsulate the sample in the combustion container. An elemental analyzer having such a configuration may be used.

Advantages of the Invention

[0017] Thus, in the elemental analysis method according to the present invention, since the sample is encapsulated in the combustion container in an inert gas atmosphere to form the sample body, for example, the sample can be kept in a non-atmosphere-exposed state from the time it is weighed until it is introduced into the heating furnace. Therefore, the influence of the atmosphere on the combustion gas extracted from the sample can be minimized, and the elemental analysis of the sample can be performed with higher accuracy than before.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0019] An elemental analysis method according to an embodiment of the present invention will be described with reference to the respective drawings.

[0020] The elemental analysis method of this embodiment is a method of quantifying elements such as C (carbon) and S (sulfur) contained in a sample by analyzing combustion gas generated when the sample burns by infrared absorption spectrometry.

[0021] As shown in FIG. 1, the elemental analyzer 100 used in this elemental analysis method has a flow pipe that forms a single gas flow path L for flowing the combustion gas generated in the heating furnace 3 together with a carrier gas (for example, oxygen gas, etc.). On the flow pipe, a dust filter 4, a dehydrating agent 5, and an infrared detector 6 are provided in series in this order. Further, on the upstream side of the heating furnace 3, an oxygen cylinder 1 for supplying oxygen gas into the heating furnace 3 and a carrier gas purifier 2 are provided.

[0022] The heating furnace 3 is configured as a high-frequency combustion furnace in which a sample accommodated therein is burned by high-frequency heating in a state where oxygen gas is supplied. In this embodiment, the sample is accommodated in the heating furnace 3 in the form of a sample body accommodated in a combustion assisting container described later. The combustion gas extracted from the sample in the heating furnace 3 flows through the flow pipe, and the concentration of C or S contained in the sample is calculated by NDIR (non-dispersive infrared gas analysis method) based on the output of the infrared detector 6.

[0023] Next, each procedure until the sample is introduced into the heating furnace 3 will be described with reference to FIG. 2.

[0024] First, as shown in FIG. 2, the mass of the sample is measured by an electronic balance 8 provided in a glove box 7 filled with an inert gas such as nitrogen and having an internal pressure higher than atmospheric pressure. The measured sample is directly placed in a combustion aid container 9 that is generally cylindrical and formed of a combustion aid such as Ni (nickel) or Cu (copper) inside the glove box 6. Here, the combustion aid container 9 includes a hollow cylindrical main body 91 whose tip side is slightly thinner than the base end side and is open, and a hollow cylindrical lid 92 having an inner diameter substantially the same as the outer diameter of the tip of the main body 1. A fitting structure 93 is formed between the tip of the main body 91 and the inner surface of the lid 92, and the inside of the combustion aid container 9 can be sealed simply by inserting the lid 92 into the main body 91. In this embodiment, in the glove box 7, after the sample is placed in the main body 91 only by manual operation of a human, the lid 92 is fitted to the tip of the main body 91 to enclose the sample, and a sample body S is formed. Here, even if the sample is in the form of a lump having a predetermined size, it can be directly enclosed in the combustion aid container 9.

[0025] An elemental analyzer 100 is arranged near the glove box 7. When the time required to transport and insert the sample body S from the glove box 7 to the heating furnace 3 is sufficiently short, the sample body S is transported while being exposed to the atmosphere as it is. Even in such a case, since the inside of the combustion aid container 9 is filled with an inert gas, the sample inside can be sufficiently kept in a non-atmospheric-exposed state.

[0026] On the other hand, a user who does not own the elemental analyzer 100 may sometimes request an analysis of a sample from someone located at a remote location. When such a commissioned analysis is performed, first, after the sample is enclosed in the combustion assisting container 9 in the glove box 7 to form the sample body S, an operation of further housing the sample body S in a vial B, which is an example of a housing body, is further added in the glove box 7. That is, since the sample is doubly protected by the inert gas in the combustion assisting container 9 and the vial B, it is possible to continuously maintain the non-exposure state to the atmosphere for the sample inside even if the time taken for transportation from the glove box 7 to the heating furnace 3 is long.

[0027] Thus, in the elemental analysis method of this embodiment, since the sample is enclosed in the combustion assisting container 9 in an inert gas atmosphere, the sample is not exposed to the atmosphere between when the sample is weighed and when it is introduced into the heating furnace 3. Therefore, for example, it is possible to prevent even a slight measurement error from occurring in the calculated elemental concentration due to alteration by oxidation or mass (weight) error of the sample due to oxidation caused by exposure of the sample to the atmosphere. For this reason, it is possible to sufficiently cope even with existing elemental analyzers in applications where high-precision elemental analysis of C and S is required.

[0028] In addition, since the combustion assisting container 9 in which the sample is enclosed is formed of a combustion assisting agent, it is not necessary to take out the sample from the combustion assisting container 9 and introduce it into the heating furnace 3, and the entire sample body S can be directly introduced into the heating furnace 3 as it is. That is, the combustion assisting container 9 itself only promotes the combustion of the sample, for example, and does not affect the concentration of the measured element, so it is not necessary to introduce only the sample into the heating furnace 3. For this reason, it is possible to prevent the sample from being exposed to the atmosphere even when the sample is introduced into the heating furnace 3, and the labor of introducing the sample into the heating furnace 3 can also be reduced. In addition, since the combustion assisting container 9 plays its role without separately adding a combustion assisting agent in addition to the sample, this also contributes to reducing the labor of the analysis.

[0029] Furthermore, in the elemental analysis method of the present embodiment, since the non-exposure state of the sample to the atmosphere can be realized only by enclosing the sample in the combustion assisting container 9 in an inert gas atmosphere, for example, there is no need to separately provide a mechanism or equipment for realizing non-exposure of the sample to the atmosphere in the heating furnace 3 of the elemental analyzer 100. Therefore, even when the structure of the heating furnace is strongly restricted as in the case of a conventional elemental analyzer using combustion gas, non-exposure of the sample to the atmosphere can be realized, and the analysis accuracy of the elements can be improved.

[0030] Other embodiments will be described.

[0031] In the above embodiment, the combustion assisting container has a cylindrical shape, but it is not limited to this, and it may have various shapes such as a rectangular tube shape. The combustion assisting container includes a main body and a lid, and preferably, the lid can be attached to the main body manually. Also, the structure formed between the main body and the lid is not limited to a fitting structure only. For example, a screwing structure may be formed between the main body and the lid. If such a screwing structure is provided, the user can enclose the sample in the combustion assisting container and easily seal the inside by simply rotating the lid with respect to the main body.

[0032] Also, the attachment of the lid to the main body may be performed using simple tools. The main body and the lid may be formed of different materials. For example, the main body may be formed of Cu and the lid may be formed of Ni, or vice versa. Furthermore, the combustion assisting container may be formed of at least one element selected from the group consisting of W (tungsten), Sn (tin), Cu (copper), Fe (iron), and Ni (nickel). With these elements, the combustion assisting container itself can function as a combustion assisting agent for promoting the combustion of the sample. Also, the main body and the lid may be formed of different types of elements selected from the above-described group.

[0033] The combustion-supporting container may be developed in a plurality of different sizes so that it can easily act as an appropriate amount of combustion-supporting agent according to the size and mass of the sample. If a plurality of types of combustion-supporting containers of different sizes are prepared in advance, the labor involved in elemental analysis can be further reduced. In addition, in order to adjust the amount of the combustion-supporting agent, not only the sample but also chips of the combustion-supporting agent may be enclosed together in the combustion-supporting container. Also, the plurality of types of combustion-supporting containers may be formed of different elements and have different sizes respectively. Further, after enclosing the sample in a certain combustion-supporting container, the combustion-supporting container in which the sample is enclosed may be enclosed in another combustion-supporting container having a larger volume. That is, the sample body may have a nested structure formed by a plurality of combustion-supporting containers. Of course, it is not limited to the case where it is enclosed in the innermost sample container among the plurality of nested combustion-supporting containers. For example, it may be enclosed in the space formed between the plurality of nested combustion-supporting containers. If combustion-supporting containers that are formed of different elements and can form a nested structure with different sizes are prepared in advance, a combination of a plurality of combustion-supporting containers forming the nested structure can be appropriately selected, and while realizing a combination suitable for promoting the combustion of the sample, the sample can be made less likely to be exposed to the atmosphere.

[0034] The operation of enclosing the sample in the combustion-supporting container does not necessarily have to be performed in a glove box, and it may be performed in an inert gas atmosphere. For example, the sample enclosure operation may be performed while blowing an inert gas around the combustion-supporting container.

[0035] In the above-described embodiment, weighing of the sample and enclosing the sample in the combustion container were performed manually. However, for example, all operations such as weighing by a machine, enclosing the sample in the combustion container, extracting the combustion gas, and analyzing the elements contained in the sample may be automatically performed by the machine. Even in such a case, if the weighing of the sample and the enclosing of the sample in the combustion container are configured to be performed in an inert gas atmosphere, the moment when the sample is exposed to the atmosphere can be eliminated, and the accuracy of the elemental analysis can be improved. More specifically, the elemental analyzer may include an encloser that encloses a sample in a combustion container formed of a combustion aid to form a sample body, an inserter that inserts the sample body into the heating furnace, an extraction mechanism that heats the sample body in the heating furnace and extracts the combustion gas generated when the sample burns, and an analyzer that analyzes the elements contained in the sample based on the combustion gas. Further, if the combustion container includes a main body and a lid attached to the main body, and the encloser is configured to attach the lid to the main body in an inert gas atmosphere and enclose the sample in the combustion container, it is sufficient.

[0036] In addition, combinations of various embodiments and combinations of parts of each embodiment may be made as long as they do not depart from the spirit of the present invention.

Explanation of Reference Numerals

[0037] 100 ··· Elemental analyzer 3 ··· Heating furnace 7 ··· Glove box 9 ··· Combustion container 91 ··· Main body 92 ··· Lid 93 ··· Fitting structure

Claims

1. An elemental analysis method for heating a sample in a heating furnace to which oxygen is supplied, comprising: an encapsulation step of encapsulating the sample in a combustion-supporting container formed of a combustion-supporting agent to form a sample body; an input step of introducing the sample body into the heating furnace; an extraction step of heating the sample body in the heating furnace and extracting combustion gas generated by combustion of the sample; an analysis step of analyzing elements contained in the sample based on the combustion gas, wherein the combustion-supporting container includes a main body and a lid attached to the main body, and the lid is attached to the main body in an inert gas atmosphere so that the sample is encapsulated in the combustion-supporting container.

2. The elemental analysis method according to claim 1, wherein the combustion-supporting container further includes a fitting structure or a screwing structure formed between the main body and the lid.

3. The elemental analysis method according to any one of claims 1 or 2, wherein the combustion-supporting container is formed of at least one element selected from the group consisting of W (tungsten), Sn (tin), Cu (copper), Fe (iron), and Ni (nickel).

4. The elemental analysis method according to any one of claims 1 to 3, wherein the main body and the lid of the combustion-supporting container are each formed of a different element.

5. The elemental analysis method according to any one of claims 1 to 4, wherein a plurality of types of the combustion-supporting containers having different sizes are prepared in advance.

6. The elemental analysis method according to any one of claims 1 to 5, wherein the encapsulation step is performed in a glove box filled with an inert gas inside.

7. The elemental analysis method according to claim 6, wherein the sample is weighed in the glove box.

8. The elemental analysis method according to any one of claims 1 to 7, further comprising an airtight transfer step of accommodating the sample body in a container in an inert gas atmosphere and transferring the sample body to the heating furnace.

9. The elemental analysis method according to claim 8, wherein the container is a vial.

10. An elemental analysis apparatus for heating a sample in a heating furnace to which oxygen is supplied, comprising: an encapsulator for encapsulating a sample in a combustion-supporting container formed of a combustion-supporting agent to form a sample body; an inputter for introducing the sample body into the heating furnace; an extraction mechanism for heating the sample body in the heating furnace and extracting combustion gas generated by combustion of the sample; An analyzer configured to analyze elements contained in the sample based on the combustion gas, wherein the auxiliary combustion container includes a main body and a lid attached to the main body, and the encapsulator is configured to attach the lid to the main body in an inert gas atmosphere to encapsulate the sample in the auxiliary combustion container. An element analyzer characterized by this.

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