Recovery liquid generating device for combustion ion chromatograph

Abstract

The present invention is provided with: a combustion tube (16) for generating a component to be recovered by combusting a sample; a carrier gas supply unit (23) for supplying a carrier gas to the combustion tube (16) such that the component to be recovered generated in the combustion tube (16) flows out from an outlet of the combustion tube (16) by means of the carrier gas; an absorption unit (6) having a plurality of absorption tubes (30) each accommodating an absorption liquid for absorbing and recovering the component to be recovered, and an absorption tube selection valve (34) for selecting an absorption tube (30) to be fluidly connected to the outlet of the combustion tube (16) from among the plurality of absorption tubes; and a control unit (36) that controls the operation of the absorption unit (6) such that the component to be recovered generated from the sample introduced into the combustion tube (16) is recovered by the predetermined absorption tube (30).

Description

Technical Field

[0001] The invention relates to a recovery liquid generating device for generating recovery liquid in a combustion ion chromatograph. Background Art

[0002] It is known that a technology using combustion ion chromatography is used to analyze total organic fluoride (TOF) (refer to non-patent document 1). In order to perform combustion ion chromatography, an analysis system having at least a combustion section, an absorption section, and a detection section (ion chromatograph) is constructed. In this analysis system, when a sample is introduced into a combustion tube in the combustion section, the organic fluorine compound contained in the sample is converted into hydrogen fluoride, and is sent to an absorption tube provided in the absorption section by a carrier gas passing through the combustion tube, and the hydrogen fluoride is absorbed by an absorption liquid in the absorption tube to generate a recovery liquid. In the present application, the absorption liquid after the recovery target components such as hydrogen fluoride are recovered is referred to as "recovery liquid". In addition, at this time, if the sample is a liquid, the sample is vaporized by a one-time combustion in the combustion tube, but is cooled and condensed in the absorption liquid to return to a liquid. Thereafter, the recovery liquid in the absorption tube is injected into the ion chromatograph, and the fluoride ion F is measured by the detection. - Concentration is used to determine the concentration of organic fluorine compounds in the sample.

[0003] Prior art literature

[0004] Non-patent literature

[0005] Non-patent document 1: "Investigation on the pollution distribution of unknown organic compounds using the all-organic halogen analysis method", Yuori Suzuki, School of Earth Environment, Kyoto University www.byq.or.jp / josei / h28 / accomplishment_report / 18_report_suzuki.pdf Summary of the invention

[0006] Problem that the invention aims to solve

[0007] When multiple samples are analyzed by combustion ion chromatography, after the recovery liquid is injected into the ion chromatograph and before the next sample is introduced into the combustion tube, the absorption tube needs to be cleaned and filled with new absorption liquid. If the absorption tube is not cleaned sufficiently at this time, the fluorine remaining in the absorption tube may contaminate the recovery liquid generated from the next sample. In particular, when the sample contains only very low concentrations of organic fluorine compounds, the analysis accuracy may be greatly reduced due to the influence of such contamination.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a recovery liquid generating device which is less likely to be contaminated when a plurality of samples are analyzed by combustion ion chromatography.

[0009] Solutions for solving problems

[0010] The recovery liquid generating device for the combustion ion chromatograph involved in the present invention comprises: a combustion tube, which is used to generate a recovery target component by burning a sample; a carrier gas supply unit, which is used to supply a carrier gas to the combustion tube so that the recovery target component generated in the combustion tube flows out from the outlet of the combustion tube through the carrier gas; an absorption unit, which has a plurality of absorption tubes respectively accommodating absorption liquids for absorbing and recovering the recovery target component, and an absorption tube selection valve for selecting an absorption tube to be fluidically connected to the outlet of the combustion tube from the plurality of absorption tubes; and a control unit, which controls the operation of the absorption unit so that the recovery target component generated from the sample introduced into the combustion tube is recovered using the specified absorption tube.

[0011] Effects of the Invention

[0012] In the sample generating device involved in the present invention, the absorbing part is provided with a plurality of absorbing tubes for accommodating absorbing liquid for absorbing recovery target components, and an absorbing tube selecting valve for selecting an absorbing tube to be fluidically connected to the outlet of the combustion tube from the plurality of absorbing tubes. The control part controls the operation of the absorbing part so that the recovery target components generated from the sample supplied to the combustion tube are recovered by the specified absorbing tubes. Therefore, it is not necessary to repeatedly clean and use the same absorbing tube when analyzing a plurality of samples by combustion ion chromatography. Thus, contamination caused by insufficient cleaning in the absorbing tube is less likely to occur. In addition, in order to reduce the risk of contamination, recovery liquid for the same sample is prepared in a plurality of absorbing tubes, and a plurality of analysis results under the same conditions are obtained for the same sample, thereby obtaining analysis results with little influence of contamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic structural diagram showing one embodiment of a recovery liquid generating device for combustion ion chromatograph.

[0014] Figure 2 This is a flowchart showing an example of the recovery liquid generating operation in this embodiment.

[0015] Figure 3 This is a conceptual diagram showing an example of a method of moving the recovery liquid from the recovery liquid generating device to the ion chromatograph.

[0016] Figure 4This is a conceptual diagram showing another example of a method of moving the recovery liquid from the recovery liquid generating device to the ion chromatograph. DETAILED DESCRIPTION

[0017] Next, an embodiment of a recovery liquid generating device for combustion ion chromatograph according to the present invention will be described with reference to the accompanying drawings.

[0018] In this embodiment, the case of analyzing the concentration of organic fluorine compounds contained in a sample by combustion ion chromatography is used for illustration. As samples in this case, tap water, river water, lake water, factory drainage, etc. are cited. In addition, the present invention is not limited to this, and also includes the case of analyzing organic chlorine compounds, etc. in a sample by combustion ion chromatography. The recovery target component recovered by the absorption liquid varies depending on the compound to be analyzed.

[0019] The recovery liquid generating device 1 mainly includes a sample unit 2 , a combustion unit 4 , and an absorption unit 6 .

[0020] In the sample section 2, a plurality of sample containers 8 for accommodating samples are arranged at a predetermined position in a state of being mounted on a sample rack 10. A sample selection valve 12 is arranged in the sample section 2. The sample selection valve 12 is a multi-port valve, which is provided with a common port arranged in the center and a plurality of selection ports surrounding the common port in a concentric circle shape, and is used to selectively switch the selection port that is fluidically connected to the common port. The common port of the sample selection valve 12 is fluidly connected to a flow path 14 that is connected to a selection port of a multi-port valve of the combustion section 4 described later, and the selection port is fluidly connected to the flow path leading to each sample container. The sample to be sent to the combustion section 4 is selected by switching the sample selection valve 12.

[0021] The combustion unit 4 includes a combustion tube 16, a heating furnace 18, a syringe pump 20, a multi-port valve 22, and a carrier gas supply unit 23. The multi-port valve 22 is used to selectively switch the connection destination of the syringe pump 20, and has a common port provided in the center and a plurality of selection ports concentrically surrounding the common port, similarly to the sample selection valve 12. The syringe pump 20 is fluidically connected to the common port of the multi-port valve 22, and at least a flow path leading to a container containing a cleaning liquid, a flow path leading to a container containing an absorption liquid, a flow path leading to a drain, and a flow path leading to the combustion tube 16 are fluidically connected to each selection port.

[0022] The combustion tube 16 is heated by a heating furnace 18. The combustion tube 16 is used to burn the sample and convert the organic fluorine compound in the sample into hydrogen fluoride to be absorbed by the absorption liquid described later. The outlet of the combustion tube 16 is connected to one port of a three-way electromagnetic valve 26 via a flow path 24. The three-way electromagnetic valve 26 is a switching valve interposed between the combustion section 4 and the absorption section 6 for selectively switching the connection destination of the outlet of the combustion tube 18 between the absorption section 6 and the discharge pipe. The carrier gas supply section 23 is fluidically connected to the vicinity of the inlet of the combustion tube 16 and is used to supply the carrier gas to the combustion tube 16.

[0023] The absorption section 6 includes an absorption tube selection valve 34 and a plurality of absorption tubes 30. The plurality of absorption tubes 30 are arranged at predetermined positions in a state of being mounted on a dedicated absorption tube rack 32. An absorption liquid for absorbing hydrogen fluoride generated in the combustion tube 16 is contained in each of the plurality of absorption tubes 30. Examples of the absorption liquid include ultrapure water, and aqueous solutions containing KH2PO4, H2O2, and the like. The absorption tube selection valve 34 is used to selectively switch the absorption tube 30 to be fluidically connected to the outlet of the combustion tube 16. The absorption tube selection valve 34 is a multi-port valve having a common port arranged in the center and a plurality of selection ports concentrically surrounding the common port, similarly to the sample selection valve 12. The common port of the absorption tube selection valve 34 is fluidically connected to one port of the multi-port valve 26 via the flow path 28. One selection port of the absorption tube selection valve 34 leads to the discharge pipe, and the remaining selection ports lead to the absorption tubes 30, respectively.

[0024] The operations of the sample unit 2, the combustion unit 4, the absorption unit 6, and the three-way electromagnetic valve 26 are controlled by the control unit 36. The control unit 36 ​​is a part of the functions of a computer device, which includes: a data storage device having a storage area for storing data including programs; and a CPU (central processing unit) that executes the program stored in the data storage device.

[0025] Next, use Figure 1 Use at the same time Figure 2 An example of the operation of the sample generating device 1 implemented by the control unit 36 ​​will be described with reference to the flowchart of FIG.

[0026] As a prerequisite, the user sets the sample container 8 containing the sample for generating the recovery liquid at a predetermined position, and sets the following recovery liquid generating conditions in advance for the control unit 36: in what order the set samples are introduced into the combustion unit 6, and which absorption tube 30 is used to recover the hydrogen fluoride generated in the combustion unit 6 from each sample. In addition, the generating conditions can also be set as follows: the samples contained in the same sample container 8 are introduced into the combustion tube 16 multiple times, and the hydrogen fluoride from the same sample is recovered by different absorption tubes 30 to generate a plurality of recovery liquids from the same sample. Therefore, it is sufficient to set at least one sample container 8 in the sample unit 2.

[0027] When the setting of the generation conditions is completed and the user inputs an instruction to start preparing the sample to the control unit 36, the control unit 36 ​​switches the sample selection valve 12 and the multi-port valve 22, so that the sample container 8 containing the sample to be first introduced into the combustion unit 6 is fluidically connected to the injection pump 20, and the injection pump 20 performs a suction action to extract the target sample into the injection pump 20 (step 101).

[0028] Afterwards, the control unit 36 ​​switches the multi-port valve 22, the three-way solenoid valve 26 and the absorption tube selection valve 34 so that the absorption tube 30 set for the sample as the object is connected to the downstream of the injection pump 20 via the combustion tube 16-flow path 24-flow path 28-absorption tube selection valve 34 fluid (step 102). Afterwards, the sample is introduced from the injection pump 20 to the combustion tube 16 (step 103). The organic fluorine in the sample introduced into the combustion tube 16 is converted into hydrogen fluoride. The gas containing hydrogen fluoride generated in the combustion tube 16 is guided to the specified absorption tube 30 together with the condensed water by the carrier gas supplied from the carrier gas supply unit 23 for recovery. A specified amount of the sample in the sample sucked into the injection pump 20 is introduced into the combustion tube 16, and at the time point when all the gas generated by the combustion of the sample is guided to the absorption tube 30, the generation of the recovery liquid for the sample is completed (step 104). A recovery liquid that recovers hydrogen fluoride as a recovery target component is generated in the absorption tube 30. For example, whether the generation of the recovery liquid has been completed can be determined based on whether a predetermined time has passed since the introduction of a predetermined amount of sample from the syringe pump 20 into the combustion tube 16 was completed.

[0029] After the generation of the recovery liquid is completed, the control unit 36 ​​performs the end operation of the syringe pump 20, such as discharging the sample remaining in the syringe pump 20 into the discharge pipe (step 105). If there is a sample for which a recovery liquid is to be generated next, the syringe pump 20 can also be rinsed and cleaned by sucking the next sample into the syringe pump 20 and discharging it into the discharge pipe. The control unit 36 ​​repeats the above-mentioned steps 101 to 105 for all samples set as analysis objects (step 106).

[0030] Furthermore, the control unit 36 ​​can be configured to switch the three-way electromagnetic valve 26 to a state where the outlet of the combustion tube 16 is connected to the exhaust pipe while the absorption tube selection valve 34 is rotating to select a predetermined absorption tube 30, so as to prevent the carrier gas flowing out of the combustion tube 16 from being guided to other absorption tubes 30. Thus, even if a substance that affects the analysis remains in the flow path downstream of the combustion tube 16, such a substance can be prevented from being recovered by the absorption tube 30 that is not the target, and the occurrence of contamination can be suppressed.

[0031] In addition, since the three-way electromagnetic valve 26 is not an essential component, the flow path 24 on the outlet side of the combustion tube 16 may be directly fluidically connected to the common port of the absorption tube selection valve 34. In this case, the supply of the carrier gas from the carrier gas supply unit 23 can be stopped while the absorption tube selection valve 34 is rotating to select a predetermined absorption tube 30, thereby suppressing the occurrence of contamination.

[0032] In addition, in the present embodiment, it is configured that by setting one selection port of the absorption pipe selection valve 34 as a port leading to the discharge pipe, the flow path 28 downstream of the three-way solenoid valve 26 and the rotor slot in the absorption pipe selection valve 34 can be purged. However, this structure is not a necessary structure, and all the selection ports of the absorption pipe selection valve 34 may be fluidically connected to the absorption pipe 30, respectively.

[0033] In addition, it is preferable that the absorption tube rack 32 of the absorption section 6 is provided in the absorption section 6 in a manner that can be attached to and detached from the absorption section 6. By making the absorption tube rack 32 detachable from the absorption section 6, after the recovery liquid is generated in each of the absorption tubes 30, the recovery liquid can be removed from the absorption tubes 30. Figure 3 As shown, all the absorption tubes 30 are moved together with the absorption tube rack 32 to the vicinity of the ion chromatograph 100 to transfer the recovery liquid to the sample bottle for the ion chromatograph 100 , thereby reducing the workload of installing a plurality of absorption tubes 30 in the ion chromatograph 100 .

[0034] In addition, it is also possible to Figure 4 As shown, the plurality of absorption tubes 30 containing the recovery liquid generated by the recovery liquid generating device 1 are transferred to sample bottles of different ion chromatographs 100 to perform analysis on the plurality of samples simultaneously and in parallel. This can improve the analysis efficiency of the plurality of samples.

[0035] The above-described embodiment is only an example of an embodiment of the recovery liquid generating device according to the present invention. The embodiment of the recovery liquid generating device according to the present invention is as follows.

[0036] In one embodiment of the recovery liquid generating device involved in the present invention, it is provided with: a combustion tube, which is used to generate a recovery target component by burning a sample; a carrier gas supply unit, which is used to supply a carrier gas to the combustion tube, so that the recovery target component generated in the combustion tube flows out from the outlet of the combustion tube through the carrier gas; an absorption unit, which has a plurality of absorption tubes respectively accommodating absorption liquids for absorbing and recovering the recovery target component, and an absorption tube selection valve for selecting an absorption tube to be fluidically connected to the outlet of the combustion tube from the plurality of absorption tubes; and a control unit, which controls the operation of the absorption unit so that the recovery target component generated from the sample introduced into the combustion tube is recovered using the specified absorption tube.

[0037] In the above-mentioned mode [1] of one embodiment, the control unit is configured to control the operation of the carrier gas supply unit to stop supplying the carrier gas to the combustion tube while the absorber tube selection valve is switching the absorber tube. Thus, while the absorber tube selection valve is switching the absorber tube to be fluidically connected to the outlet of the combustion tube next, the carrier gas does not flow into the other absorber tubes, thereby suppressing the occurrence of contamination.

[0038] In the above-mentioned embodiment [2], a switching valve is further provided, the switching valve being provided between the outlet of the combustion tube and the absorber tube selection valve of the absorber section, for selectively connecting the outlet of the combustion tube to one of the absorber section and the discharge tube by fluid, and the control section is configured to control the switching valve to connect the outlet of the combustion tube to the discharge tube by fluid while the absorber tube selection valve is switching the absorber tube. Thus, while the absorber tube selection valve is switching to the absorber tube to be connected to the outlet of the combustion tube by fluid next, the carrier gas does not flow into the other absorber tubes, and the occurrence of contamination can be suppressed.

[0039] In addition, in mode [3] of the above-mentioned one embodiment, there is a sample section, which has a plurality of sample containers each containing the sample, and a sample selection valve for selecting any one of the plurality of sample containers, and is configured to extract the sample in the sample container selected by the sample selection valve and supply the sample to the combustion tube.

[0040] In the above-mentioned method [3], the control unit is configured to: link the operation of the sample selection valve of the sample unit with the operation of the absorption tube selection valve of the absorption unit, so that the absorption liquid in each of the absorption tubes absorbs the recovery target components generated from the samples in each of the plurality of sample containers.

[0041] In the aspect [4] of the above-mentioned one embodiment, the plurality of absorption tubes are mounted on a common rack, and the rack is provided on the absorption section in a manner that is attachable to and detachable from the absorption section.

[0042] Description of Reference Numerals

[0043] 1: recovery liquid generating device; 2: sample part; 4: combustion part; 6: absorption part; 8: sample container; 10: sample rack; 12: sample selection valve; 14, 24, 28: flow path; 16: combustion tube; 18: heating furnace; 20: injection pump; 22: multi-port valve; 26: three-way solenoid valve; 30: absorption tube; 32: absorption tube rack; 34: absorption tube selection valve; 36: control part.

Claims

1. A recovery liquid generating device for a combustion ion chromatograph, comprising: A combustion tube for generating a recovery target component by burning the sample; a carrier gas supply unit for supplying a carrier gas to the combustion tube so that the recovery target component generated in the combustion tube flows out from an outlet of the combustion tube through the carrier gas; an absorption section having a plurality of absorption tubes for accommodating absorption liquids for absorbing and recovering the recovery target components, and an absorption tube selection valve for selecting an absorption tube to be fluidically connected to the outlet of the combustion tube from among the plurality of absorption tubes; as well as A control unit controls the operation of the absorption unit so that the recovery target component generated from the sample introduced into the combustion tube is recovered by using the predetermined absorption tube.

2. The recovery liquid generating device according to claim 1, wherein: The control unit is configured to control the operation of the carrier gas supply unit to stop supplying the carrier gas to the combustion tube while the absorption tube selection valve is switching the absorption tube.

3. The recovery liquid generating device according to claim 1, wherein: The invention further comprises a switching valve, which is provided between the outlet of the combustion tube and the absorption tube selection valve of the absorption part and is used to selectively connect the outlet of the combustion tube to one of the absorption part and the discharge tube for fluid connection. The control unit is configured to control the switching valve to fluidically connect the outlet of the combustion tube and the discharge tube while the absorption tube selection valve is switching the absorption tube.

4. The recovery liquid generating device according to claim 1, wherein: The recovery liquid generating device includes a sample unit having a plurality of sample containers each containing the sample and a sample selection valve for selecting any one of the plurality of sample containers. The recovery liquid generating device is configured to extract the sample in the sample container selected by the sample selecting valve and supply the sample to the combustion tube.

5. The recovery liquid generating device according to claim 4, wherein: The control unit is configured to link the operation of the sample selection valve of the sample unit with the operation of the absorption tube selection valve of the absorption unit to cause the absorption liquid in each of the absorption tubes to absorb the recovery target component generated from the sample in each of the plurality of sample containers.

6. The recovery liquid generating device according to claim 1, wherein: The plurality of absorption tubes are mounted on a common rack, and the rack is provided on the absorption section in a detachable manner with respect to the absorption section.

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