JP2009288209A - Flame photometric detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately achieve, according to an analysis purpose or the like, both a single photomultiplier structure with high sensitivity and a dual photomultiplier structure capable of simultaneous detection of a plurality of components by use of one thermal insulating block. <P>SOLUTION: The thermal insulating block 1 to form a hydrogen flame therein includes a first member 10 having a cylindrical inner space 11, and a second member 20 having a hemispherical inner space 21 and a hemispherical mirror surface 22 facing thereto. By inserting the second member 20 to the first member 10 from one open end surface side thereof, both are integrated together and the cylindrical inner space 11 is connected to the hemispherical internal space 21, whereby the thermal insulating block 1 is used as the thermal insulating block for single photomultiplier. The second member 20 is removed from the first member 10, and only the first member 10 is used as the thermal insulating block 1 for dual photomultiplier. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flame photometric detector (FPD) that is mainly used as a detector of a gas chromatograph apparatus.

  Various types of detectors have been put to practical use as detectors for gas chromatograph apparatuses. Among them, the flame photometric detector is a detector that selectively detects sulfur compounds and phosphorus compounds, analysis of malodorous components such as hydrogen sulfide and methyl mercaptan, detection of trace sulfur in chemicals, residual pesticides. It is widely used for analysis and analysis of biochemical components.

  FIG. 4 is a schematic configuration diagram of a conventionally known flame photometric detector described in Patent Document 1. In FIG. A sample gas pipe 31, a hydrogen supply pipe 32, and an air supply pipe 33 connected to the column outlet of the gas chromatograph are connected to a nozzle 3 having a gas jet outlet on the upper side. A transparent quartz cylinder 34 is disposed around the nozzle 3, and the entire quartz cylinder 34 is covered with the heat retaining block 1. A heater and a temperature sensor (not shown) are embedded in the heat retaining block 1, and thereby the heat retaining block 1 is maintained at a predetermined temperature.

  A detection window 36 in which a convex lens 37 is disposed is opened to the side of the heat insulation block 1, and the interference filter 5 and the photoelectron increase are connected to the outside of the detection window 36 via a connection cylinder 4 having a cooling fin. A double pipe 6 is provided. The inner wall of the heat retaining block 1 opposite to the convex lens 37 is formed in a spherical shape across the hydrogen flame frame 7 formed on the upper part of the nozzle 3, and the inner surface thereof is a concave mirror 35 formed by deposition of a metal film or the like.

  Carrier gas such as nitrogen supplied through the sample gas pipe 31, hydrogen gas supplied through the hydrogen supply pipe 32, and air supplied through the air supply pipe 33 are mixed at the tip of the nozzle 3, and this is combusted to generate hydrogen. A flame frame 7 is formed. When the sample component flowing out from the column of the gas chromatograph is introduced into the hydrogen flame frame 7, the sample component burns and emits light having a specific wavelength. In particular, in a perhydrogen reducing flame, light having a wavelength of 394 [μm] and 526 [μm] is emitted by combustion of a sulfur compound and a phosphorus compound, respectively. The light emitted from the hydrogen flame frame 7 passes through the transparent quartz tube 34, and only the light having a specific wavelength is selectively transmitted by the interference filter 5 and reaches the photomultiplier tube 6.

  The light emitted from the sample component burning portion 7 a in the hydrogen flame frame 7 diffuses in all directions, but the light that travels in the right direction in FIG. 4 and reaches the convex lens 37 is collimated by the convex lens 37. Therefore, most of the light that has passed through the convex lens 37 enters the interference filter 5 almost perpendicularly, and only light having a specific wavelength corresponding to the wavelength characteristic of the interference filter 5 is transmitted to reach the photomultiplier tube 6.

  On the other hand, the light traveling in the left direction in FIG. 1 and reaching the concave mirror 35 is reflected by the concave mirror 35 in a direction almost opposite to the incident direction. Therefore, the reflected light passes through the vicinity of the burning part 7a and reaches the convex lens 37. For this reason, in addition to the light directly reaching the convex lens 37 from the burning part 7 a as described above, this reflected light is also converted into parallel light by the convex lens 37 and sent to the interference filter 5. Accordingly, the amount of light incident on the photomultiplier tube 6 is considerably increased as compared with the case where the concave mirror 35 is not provided, so that high detection sensitivity can be achieved. Such a structure of a flame photometric detector using a single photomultiplier tube is referred to as a single photomultiplier (single filter or total light reflection) type.

  Although the single photomultiplier flame photometric detector is highly sensitive, it can detect only the component corresponding to the passing wavelength of the mounted interference filter 5. Therefore, it cannot be detected simultaneously with the sulfur compound and the phosphorus compound, and when analyzing a sample in which both compounds are mixed, for example, it is necessary to replace the interference filter and perform the analysis twice, which is troublesome.

  On the other hand, a so-called dual photomultiplier flame luminous intensity comprising two interference filters that transmit light of wavelengths respectively corresponding to phosphorus and sulfur and two photomultiplier tubes that respectively detect the transmitted light. A detector is conventionally known (see Patent Document 2). In this detector, detection windows are provided at two opposing positions on the side of the heat insulation block, and an interference filter and a photomultiplier tube are provided outside each detection window. Thereby, the light emitted from the burning part in the hydrogen flame flame can be simultaneously introduced into the two photomultiplier tubes, and light of different wavelengths can be detected. However, in the case of this structure, unlike the single photomal type, since the reflected light from the spherical concave mirror cannot be used, it is inevitable that the sensitivity is sacrificed.

  As described above, the single photomal type and the dual photomal type have advantages and disadvantages, respectively.

JP-A-11-237340 Japanese Patent Laid-Open No. 11-237339

  Conventionally, a single photomultiplier flame photometric detector and a dual photomultiplier flame photometric detector are provided to users as completely separate devices. Therefore, a user who has purchased a single photomultiplier flame photometric detector has to perform a plurality of analyzes when he / she wants to analyze a plurality of components. As a result, not only is it time-consuming and time-consuming, but it is also necessary to prepare an extra amount of sample. In order to avoid such an increase in time and analysis time, it is necessary to purchase a dual photomal type device. However, it requires extra cost, and if multiple simultaneous analyzes are required only infrequently, a large waste occurs. It will be.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to perform high-sensitivity analysis by single photomal type and simultaneous analysis of multiple components by dual photomal type according to the purpose of analysis. It is in providing the flame photometric detector which can select suitably.

In order to solve the above problems, the present invention is directed to introducing a sample component into a flame flame generated inside a heat insulation block and burning it, and taking out the light emitted by the combustion from the heat insulation block and specifying it. In the flame photometric detector introduced into the photodetector through a transmission means that transmits light of the wavelength of
The heat retaining block includes a first member having openings at both end surfaces and an inner wall that is substantially cylindrical, and a second member that is attachable to one opening of the first member and whose inner wall is a concave mirror surface; Consists of
In a state where the second member is attached to the first member, a single photomal type configuration for detecting light extracted from the other opening of the first member, and the first member without using the second member. It is characterized in that it is possible to select a dual photomal type configuration that detects light extracted from both openings of the member.

  In addition, by making the substantially cylindrical inner wall surface of the first member a mirror surface, it is possible to take out more light from the heat insulation block in any case of a single photomultiplier type or a dual photomultiplier type. Can be introduced.

  Further, in the second member, it is preferable that the concave mirror surface has a circular shape centering on the combustion portion in the hydrogen flame frame.

  In the flame photometric detector according to the present invention, by attaching the second member to one opening of the first member, the first of the light emitted from the combustion portion of the hydrogen flame frame formed inside the heat retaining block. The light traveling toward the member side is reflected by the concave mirror and travels toward the other opening. That is, as in the case of using an integral heat insulating block as shown in FIG. 4, the light emitted to the side opposite to the side where the photodetector is installed is also effectively used for detecting the sample component. can do. Therefore, when a single photomal type configuration is adopted, high detection sensitivity can be achieved.

  On the other hand, the second member is removed from the first member and only the first member is used as a heat insulation block, and transmission means (interference filters) and light detectors (photomultiplier tubes) having different wavelength characteristics are provided in the openings on both sides thereof. In the case of mounting, since the condensing effect by the concave mirror cannot be obtained, a plurality of components can be detected at the same time, although the detection sensitivity is lower than that of the single photomal type configuration. Thus, when adopting a dual photomal type configuration, it is possible to achieve simultaneous analysis of a plurality of components, which was impossible with the single photomal type.

  As described above, according to the flame photometric detector according to the present invention, a single heat insulating block is used, and a single photomal type configuration and a dual photomal type configuration are used depending on the purpose of analysis and the type of sample. Can be easily rearranged. Accordingly, even if the user does not purchase two types of detectors, high-sensitivity single component analysis and simultaneous analysis of a plurality of components can be selectively performed as appropriate although sensitivity is slightly reduced.

  An embodiment of a flame photometric detector according to the present invention will be described with reference to FIGS. FIG. 1 is a schematic longitudinal sectional view of a heat retaining block 1 which is a main component of the flame photometric detector according to the present embodiment. FIG. 2 is a schematic configuration diagram when the flame photometric detector according to the present embodiment is used as a single photomultiplier type. FIG. 3 is a schematic configuration diagram when the flame photometric detector according to the present embodiment is used as a dual photomultiplier type.

  As shown in FIG. 1B, the heat insulation block 1 in the flame photometric detector of the present embodiment is roughly used in two members, that is, in any configuration of single photomultiplier type / dual photomultiplier type. It consists of a first member 10 and a second member 20 used only in a single photomal type configuration. Both members 10 and 20 can be made by cutting a metal body such as stainless steel.

  The 1st member 10 has the substantially cylindrical internal space 11 with which both end surfaces were open | released, The inner wall surface is the mirror surface 12 so that light can be reflected. Although not shown, the first member 10 has an opening for attaching a nozzle, which will be described later, and an opening such as an exhaust hole for communicating the internal space 11 with the outside in addition to the openings at both ends. .

  The second member 20 has an outer shape that can be inserted inside one end face opening of the first member 10, and the inside thereof is cut into a substantially hemispherical shape to form a hemispherical internal space 21. The inner wall surface facing the hemispherical inner space 21 is a mirror surface 22 so that light can be reflected. Both the mirror surfaces 12 and 22 of the first member 10 and the second member 20 are subjected to surface processing for removing fine irregularities on the surface of the metal body, and then a predetermined metal is deposited to form a metal thin film. Thus, a highly efficient reflecting surface is obtained. Of course, the mirror surfaces 12 and 22 may be formed by other methods.

  When the second member 20 is completely inserted into the internal space 11 of the first member 10, as shown in FIG. 1A, approximately half of the cylindrical internal space 11 and the hemispherical internal space 21 are connected. The heat insulating block 1 is formed with an internal space in which only one end face is opened. At this time, almost all surfaces facing the internal space are mirror surfaces 12 and 22.

  When used as a single photomal type configuration, as shown in FIG. 1A, the nozzle 3 is attached to the heat insulating block 1 formed by integrating both members 10 and 20, and the only end face of the heat insulating block 1 is provided. Using the opening as a detection window, the connecting cylinder 4 is attached to the outside, and the interference filter 5 and the photomultiplier tube 6 are attached through the connecting cylinder 4. That is, the configuration shown in FIG. Here, a quartz tube and a convex lens surrounding the hydrogen flame frame 7 are not described, but it is naturally possible to attach such a member, which is basically the same as the single-photomal configuration shown in FIG. Become.

  That is, the hydrogen flame frame 7 is formed above the tip of the nozzle 3 and the sample components are burned therein to generate light specific to the components. The light is reflected by the semicircular mirror surface 22, and the dissipated light is also reflected by the mirror surface 12 and efficiently introduced into the interference filter 5. Only the wavelength light peculiar to the interference filter 5 is selected and photoelectron is selected. It introduces into the multiplier 6 and detects. The interference filter 5 may have a characteristic of transmitting light having a wavelength corresponding to, for example, phosphorus or sulfur. Thereby, the target component can be detected with high sensitivity.

  On the other hand, when used as a dual photomal type configuration, the second member 20 is removed from the first member 10 as shown in FIG. A nozzle 3 is attached, and two end face openings on both sides of the heat retaining block 1 are used as detection windows, and connecting cylinders 4a and 4b are respectively attached to the outside thereof, through which interference filters 5a and 5b and a photomultiplier tube 6a are attached. , 6b is attached. That is, the configuration shown in FIG. 3 is obtained. Again, a quartz tube or a convex lens surrounding the hydrogen flame frame 7 is not shown, but it is naturally possible to attach such a member. For example, one of the two interference filters 5a and 5b (5a) has a characteristic of transmitting light having a wavelength corresponding to phosphorus, and the other (5b) has a characteristic of transmitting light having a wavelength corresponding to sulfur. That's fine.

  At the time of analysis, a hydrogen flame frame 7 is formed above the tip of the nozzle 3 and the sample component is burned therein to generate light specific to the component. The light emitted from the hydrogen flame frame 7 is simultaneously introduced into the interference filters 5a and 5b on both sides. In the interference filter 5a, only the wavelength light corresponding to phosphorus is selected and introduced into the photomultiplier 6a. In the interference filter 5b, only light having a wavelength corresponding to sulfur is selected and introduced into the photomultiplier 6b. Thereby, even if a plurality of components (phosphorus compound and sulfur compound) are mixed in the sample gas supplied to the nozzle 3, they can be detected independently.

  As described above, in the flame photometric detector of this embodiment, by using one heat retaining block 1 and appropriately combining an interference filter, a photomultiplier tube, etc., a single photomultiplier type and a dual photomultiplier type are used. Can be configured freely.

  The above-described embodiment is an example, and it is obvious that changes and modifications can be made as appropriate within the scope of the present invention.

The schematic longitudinal cross-sectional view of the heat retention block which is a main structural member of the flame photometric detector by one Example of this invention. The schematic block diagram in the case of using the flame photometric detector by a present Example as a single photomal type | mold. The schematic block diagram in the case of using the flame photometric detector by a present Example as a dual photomultiplier type. The schematic block diagram of the flame photometric detector conventionally known.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Thermal insulation block 10 ... 1st member 11 ... Internal space 12 ... Mirror surface 20 ... 2nd member 21 ... Hemispherical internal space 22 ... Mirror surface 3 ... Nozzle 31 ... Sample gas pipe 32 ... Hydrogen supply pipe 33 ... Air supply pipe 4, 4a, 4b ... Connection cylinder 5, 5a, 5b ... Interference filter 6, 6a, 6b ... Photomultiplier tube 7 ... Hydrogen flame frame 7a ... Combustion part

Claims (1)

Sample components are introduced into the flame flame generated inside the heat insulation block and burned, and the light emitted by the combustion is taken out of the heat insulation block and introduced into the photodetector through a transmission means that transmits light of a specific wavelength. In the flame photometric detector that
The heat retaining block includes a first member having openings at both end surfaces and an inner wall that is substantially cylindrical, and a second member that is attachable to one opening of the first member and whose inner wall is a concave mirror surface; Consists of
In a state where the second member is attached to the first member, a single photomal type configuration for detecting light extracted from the other opening of the first member, and the first member without using the second member. A flame photometric detector characterized by being able to select a dual photomal type configuration that respectively detects light extracted from both openings of a member.

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