Recovery liquid generator for combustion ion chromatograph

Abstract

This recovery solution generating device comprises: a combustion tube (16) for generating a recovery target component by burning a sample; a carrier gas supply unit (23) for supplying a carrier gas to the combustion tube (16) and causing the recovery target component generated in the combustion tube (16) to flow out from an outlet of the combustion tube (16) by means of the carrier gas; an absorption unit (6) including a plurality of absorption tubes (30) each accommodating an absorption liquid for absorbing and recovering the recovery target component, and an absorption tube selection valve (34) for selecting one of the absorption tubes (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) for controlling the operation of the absorption unit (6) such that the recovery target component generated from the sample introduced into the combustion tube (16) is recovered by a prescribed one of the absorption tubes (30).

Description

[Technical Field]

[0001] The present invention relates to a recovered liquid generating device for generating a recovered liquid in a combustion ion chromatograph. [Background technology]

[0002] It is known to use combustion ion chromatography analysis to analyze total organic fluorine (TOF) (see Non-Patent Document 1). To perform combustion ion chromatography analysis, an analytical system is constructed that includes at least a combustion section, an absorption section, and a detection section (ion chromatograph). In such an analytical system, when a sample is introduced into a combustion tube in the combustion section, the organic fluorine compounds contained in the sample are converted to hydrogen fluoride, which is then transported to an absorption tube provided in the absorption section by a carrier gas passing through the combustion tube. The hydrogen fluoride is absorbed by an absorption liquid in the absorption tube, and a recovered liquid is produced. In this application, the absorbed liquid after recovering the target components such as hydrogen fluoride is referred to as the "recovered liquid." In addition, if the sample is liquid, it is first gasified by combustion in the combustion tube, but is cooled and condensed in the absorption liquid to return to a liquid. The recovered liquid in the absorption tube is then injected into an ion chromatograph, and fluoride ions F are extracted. - By measuring the concentration, the concentration of the organofluorine compound in the sample is determined. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] "Survey of the distribution of unknown organic fluorine compounds using total organic halogen analysis," by Hiroori Suzuki, Graduate School of Global Environmental Studies, Kyoto University. www.byq.or.jp / josei / h28 / accomplishment_report / 18_report_suzuki.pdf Summary of the Invention [Problem to be solved by the invention]

[0004] When analyzing multiple samples using combustion ion chromatography, after injecting the recovery liquid into the ion chromatograph, the absorption tube must be washed and filled with new absorption liquid before introducing the next sample into the combustion tube. If the absorption tube is not washed properly, residual fluorine in the absorption tube may contaminate the recovery liquid generated from the next sample. In particular, if the sample contains only a very low concentration of organic fluorine compounds, such contamination may significantly reduce the analytical accuracy.

[0005] The present invention has been made in consideration of the above problems, and aims to provide a recovered liquid generating device that is less likely to cause contamination when analyzing multiple samples using combustion ion chromatography analysis. [Means for solving the problem]

[0006] The recovery liquid generation device for a combustion ion chromatograph according to the present invention comprises a combustion tube for generating recovery target components by combusting a sample; a carrier gas supply unit for supplying a carrier gas to the combustion tube and causing the recovery target components generated in the combustion tube to flow out of an outlet of the combustion tube by the carrier gas; an absorption unit having a plurality of absorption tubes each containing an absorption liquid for absorbing and recovering the recovery target components and an absorption tube selection valve for selecting an absorption tube from the plurality of absorption tubes to be fluidly connected to the outlet of the combustion tube; and a control unit for controlling the operation of the absorption unit so that the recovery target components generated from the sample introduced into the combustion tube are recovered in a predetermined absorption tube. [Effects of the Invention]

[0007] In the sample preparation device according to the present invention, the absorption unit includes a plurality of absorption tubes, each containing an absorption liquid for absorbing the target components, and an absorption tube selection valve for selecting an absorption tube from the plurality of absorption tubes to be fluidly connected to the outlet of the combustion tube. The control unit controls the operation of the absorption unit so that the target components generated from the sample supplied to the combustion tube are collected in a predetermined absorption tube. This eliminates the need to repeatedly clean and reuse the same absorption tube when analyzing multiple samples by combustion ion chromatography. This reduces the risk of contamination due to insufficient cleaning of the absorption tube. Furthermore, to reduce the risk of contamination, recovery liquid for the same sample can be prepared in multiple absorption tubes, allowing multiple analysis results for the same sample under the same conditions to be obtained, thereby reducing the impact of contamination. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing an embodiment of a recovery liquid producing device for combustion ion chromatography; [Figure 2] 10 is a flowchart showing an example of a recovery liquid producing operation in the embodiment. [Figure 3] FIG. 10 is a conceptual diagram showing an example of a method for transferring a recovered liquid from a recovered liquid generation device to an ion chromatograph. [Figure 4] FIG. 10 is a conceptual diagram showing another example of a method for transferring the recovered liquid from the recovered liquid generation device to the ion chromatograph. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of a recovery liquid producing apparatus for combustion ion chromatography according to the present invention will be described with reference to the drawings.

[0010] In this example, the analysis of the concentration of organic fluorine compounds contained in a sample using combustion ion chromatography will be described as an example. Examples of samples in this case include tap water, river water, lake water, and industrial wastewater. However, the present invention is not limited to this example, and also includes cases where organic chlorine compounds in a sample are analyzed using combustion ion chromatography. The components to be recovered using the absorption liquid vary depending on the compound to be analyzed.

[0011] The recovered liquid generating device 1 mainly includes a sampling section 2, a combustion section 4, and an absorption section 6.

[0012] In the sample section 2, a plurality of sample containers 8 containing samples are set in a predetermined position while being mounted on a sample rack 10. The sample section 2 is provided with a sample selection valve 12. The sample selection valve 12 is a multi-port valve that has a common port provided in the center and a plurality of selection ports concentrically surrounding the common port, and selectively switches the selection ports that are fluidly connected to the common port. The common port of the sample selection valve 12 is fluidly connected to a flow path 14 that leads to one selection port of the multi-port valve of the combustion section 4 described below, and the selection ports are fluidly connected to flow paths that lead to each of the sample containers. By switching the sample selection valve 12, the sample to be sent to the combustion section 4 is selected.

[0013] The combustion unit 4 includes a combustion tube 16, a heating furnace 18, a syringe pump 20, a multiport valve 22, and a carrier gas supply unit 23. The multiport valve 22 is used to selectively switch the connection destination of the syringe pump 20, and, like the sample selection valve 12, has a common port located in the center and multiple selection ports concentrically surrounding the common port. The syringe pump 20 is fluidly connected to the common port of the multiport valve 22, and each selection port is fluidly connected to 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.

[0014] The combustion tube 16 is heated by a heating furnace 18. The combustion tube 16 burns a sample to convert organofluorine compounds in the sample into hydrogen fluoride, which is absorbed in an absorption liquid described below. The outlet of the combustion tube 16 is connected to one port of a three-way solenoid valve 26 via a flow path 24. The three-way solenoid valve 26 is interposed between the combustion section 4 and the absorption section 6 and is a switching valve for selectively switching the connection destination of the outlet of the combustion tube 18 between the absorption section 6 and the drain. A carrier gas supply section 23 is fluidly connected near the inlet of the combustion tube 16, and supplies carrier gas to the combustion tube 16.

[0015] The absorption section 6 includes multiple absorption tubes 30 and an absorption tube selection valve 34. The multiple absorption tubes 30 are mounted on a dedicated absorption tube rack 32 and set in a predetermined position. Each of the multiple absorption tubes 30 contains an absorption liquid for absorbing hydrogen fluoride produced in the combustion tube 16. Examples of the absorption liquid include ultrapure water, KH2PO4, and an aqueous solution containing H2O2. The absorption tube selection valve 34 selectively switches the absorption tube 30 fluidly connected to the outlet of the combustion tube 16. Similar to the sample selection valve 12, the absorption tube selection valve 34 is a multiport valve having a central common port and multiple selection ports concentrically surrounding the common port. The common port of the absorption tube selection valve 34 is fluidly connected to one port of the multiport valve 26 via the flow path 28. One selection port of the absorption tube selection valve 34 is connected to the drain, and the remaining selection ports are each connected to an absorption tube 30.

[0016] The operations of the sample section 2, combustion section 4, absorption section 6, and three-way solenoid valve 26 are controlled by a control section 36. The control section 36 is a functional part of a computer device that includes a data storage device having a memory area for storing data including programs, and a CPU (Central Processing Unit) that executes the programs stored in the data storage device.

[0017] Next, an example of the operation of the sample preparation device 1 realized by the control unit 36 ​​will be described with reference to the flowchart of FIG. 2 together with FIG.

[0018] As a premise, the user sets sample containers 8 containing samples from which recovery liquids are to be generated in predetermined positions in the control unit 36, and sets recovery liquid generation conditions such as the order in which the set samples will be introduced into the combustion unit 6 and which absorption tubes 30 will be used to recover hydrogen fluoride derived from each sample generated in the combustion unit 6. It is also possible to set generation conditions so that samples contained in the same sample container 8 are introduced into the combustion tube 16 multiple times, and hydrogen fluoride derived from the same sample is recovered in different absorption tubes 30, thereby generating multiple recovery liquids derived from the same sample. Therefore, it is sufficient that at least one sample container 8 is set in the sample unit 2.

[0019] Once the setting of the generation conditions is complete and the user inputs an instruction to the control unit 36 ​​to start sample preparation, the control unit 36 ​​first switches the sample selection valve 12 and the multiport valve 22 so that the sample container 8 containing the sample to be introduced into the combustion unit 6 is fluidly connected to the syringe pump 20, and then causes the syringe pump 20 to perform an inhalation operation to collect the target sample into the syringe pump 20 (step 101).

[0020] The control unit 36 ​​then switches the multiport valve 22, the three-way solenoid valve 26, and the absorption tube selection valve 34 so that the absorption tube 30 selected for the target sample is fluidly connected downstream of the syringe pump 20 via the combustion tube 16, the flow path 24, the flow path 28, and the absorption tube selection valve 34 (step 102). Then, the introduction of the sample from the syringe pump 20 into the combustion tube 16 begins (step 103). Organic fluorine in the sample introduced into the combustion tube 16 is converted to hydrogen fluoride. The hydrogen fluoride-containing gas generated in the combustion tube 16 is guided together with condensed water by the carrier gas supplied from the carrier gas supply unit 23 to the designated absorption tube 30 and collected. When a predetermined amount of the sample drawn into the syringe pump 20 is introduced into the combustion tube 16 and all the gas generated by the combustion of the sample is introduced into the absorption tube 30, the production of the recovery liquid for that sample is completed (step 104). A recovery liquid containing the hydrogen fluoride, the target component, is produced in the absorption tube 30. Whether or not the production of the recovery liquid is complete can be determined, for example, by whether or not a predetermined time has elapsed since the introduction of a predetermined amount of sample from the syringe pump 20 into the combustion tube 16 was completed.

[0021] After the production of the recovery liquid is completed, the control unit 36 ​​performs a termination operation of the syringe pump 20, such as discharging the sample remaining in the syringe pump 20 to the drain (step 105). If there is a sample for which recovery liquid should be produced next, the next sample can be sucked into the syringe pump 20 and discharged to the drain, thereby performing co-washing inside the syringe pump 20. The control unit 36 ​​repeatedly executes the operations of steps 101 to 105 for all samples set as analysis targets (step 106).

[0022] The control unit 36 ​​can be configured to switch the three-way solenoid valve 26 to a state in which the outlet of the combustion tube 16 is connected to the drain, so that the carrier gas flowing out of the combustion tube 16 is not directed to another absorption tube 30, while the absorption tube selection valve 34 is rotating to select a predetermined absorption tube 30. This prevents substances that may affect the analysis from being collected by an absorption tube 30 that is not the target, even if such substances remain in the flow path downstream of the combustion tube 16, and thus reduces the occurrence of contamination.

[0023] Furthermore, since the three-way solenoid valve 26 is not an essential component, the flow path 24 on the outlet side of the combustion tube 16 may be directly fluidly connected to the common port of the absorption tube selection valve 34. In this case, contamination can also be prevented by stopping the supply of carrier gas from the carrier gas supply unit 23 while the absorption tube selection valve 34 is rotating to select a predetermined absorption tube 30.

[0024] In this embodiment, one selection port of the absorption tube selection valve 34 is connected to the drain, thereby enabling purging of the flow path 28 downstream of the three-way solenoid valve 26 and the rotor groove in the absorption tube selection valve 34. However, this is not an essential configuration, and all selection ports of the absorption tube selection valve 34 may be fluidly connected to the absorption tubes 30, respectively.

[0025] The absorption tube rack 32 of the absorption unit 6 is preferably set so as to be detachable from the absorption unit 6. By making the absorption tube rack 32 detachable from the absorption unit 6, after recovery liquid has been produced in each of the absorption tubes 30, all of the absorption tubes 30 together with the absorption tube rack 32 can be moved near the ion chromatograph 100 as shown in Fig. 3, and the recovery liquid can be transferred to a sample vial for the ion chromatograph 100, thereby reducing the workload of setting multiple absorption tubes 30 in the ion chromatograph 100.

[0026] 4, multiple absorption tubes 30 containing the recovered liquid generated by the recovered liquid generating device 1 can be transferred to sample vials of separate ion chromatographs 100, allowing for simultaneous parallel analysis of multiple samples. This improves the efficiency of analyzing multiple samples.

[0027] The embodiment described above is merely one example of the embodiment of the recovered liquid generation device according to the present invention. The embodiment of the recovered liquid generation device according to the present invention is as follows.

[0028] One embodiment of the recovery liquid generation device according to the present invention includes a combustion tube for generating recovery target components by combusting a sample; a carrier gas supply unit for supplying a carrier gas to the combustion tube and causing the recovery target components generated in the combustion tube to flow out of an outlet of the combustion tube by the carrier gas; an absorption unit having a plurality of absorption tubes each containing an absorption liquid for absorbing and recovering the recovery target components and an absorption tube selection valve for selecting an absorption tube from the plurality of absorption tubes to be fluidly connected to the outlet of the combustion tube; and a control unit for controlling the operation of the absorption unit so that the recovery target components generated from the sample introduced into the combustion tube are recovered in a predetermined absorption tube.

[0029] In aspect [1] of the above embodiment, the control unit is configured to control the operation of the carrier gas supply unit and stop the supply of the carrier gas to the combustion tube while the absorption tube selection valve is switching the absorption tube, thereby preventing the carrier gas from flowing into another absorption tube while the absorption tube selection valve is switching toward the absorption tube that is to be next fluidly connected to the outlet of the combustion tube, thereby suppressing the occurrence of contamination.

[0030] In addition, in aspect [2] of the above embodiment, a switching valve is provided between the outlet of the combustion tube and the absorber tube selection valve of the absorption section, for selectively fluidly connecting the outlet of the combustion tube to either the absorber tube or a drain, and the control section is configured to control the switching valve to fluidly connect the outlet of the combustion tube to the drain while the absorber tube selection valve is switching the absorber tube. This prevents carrier gas from flowing into another absorber tube while the absorber tube selection valve is switching to the absorber tube that is to be next fluidly connected to the outlet of the combustion tube, thereby suppressing contamination.

[0031] In addition, in aspect [3] of the above embodiment, a sample section is provided having a plurality of sample containers each containing the sample, and a sample selection valve for selecting one of the plurality of sample containers, and the sample in the sample container selected by the sample selection valve is collected and supplied to the combustion tube.

[0032] In the above aspect [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, and to absorb the target components to be recovered produced from the samples in each of the multiple sample containers into the absorption liquid in the separate absorption tubes.

[0033] In addition, in the aspect [4] of the above embodiment, the plurality of absorption tubes are mounted on a common rack that is detachably set in the absorption section. [Explanation of symbols]

[0034] 1. Recovery liquid generation device 2 Sample section 4 Combustion section 6 Absorption section 8 Sample Containers 10 sample racks 12 Sample Selection Valve 14, 24, 28 Flow path 16 Combustion tube 18 Furnace 20 Syringe Pump 22 Multiport valve 26 3-way solenoid valve 30 Absorber tube 32 Absorber tube rack 34 Absorber tube selection valve 36 Control Unit

Claims

1. a combustion tube for combusting the sample to produce the components to be recovered; A carrier gas supply unit that supplies a carrier gas to the combustion tube and causes the recovery target components generated in the combustion tube to flow out of an outlet of the combustion tube by the carrier gas; an absorption unit including a plurality of absorption tubes each containing an absorption liquid for absorbing and recovering the target components, and an absorption tube selection valve for selectively switching among the plurality of absorption tubes which absorption tubes are fluidly connected to the outlet of the combustion tube; a control unit that controls the operation of the absorption unit so that the target components to be recovered generated from the sample introduced into the combustion tube are recovered in a predetermined absorption tube, the control unit is configured to control the operation of the carrier gas supply unit and stop the supply of the carrier gas to the combustion tube while the absorption tube selection valve is performing an operation to switch the absorption tube fluidly connected to the outlet of the combustion tube.

2. The absorption tube selection valve is a multi-port valve having a common port and a plurality of selection ports concentrically surrounding the common port, the outlet of the combustion tube is fluidly connected to the common port, the plurality of absorption tubes are fluidly connected to the plurality of selection ports respectively, and the recovery liquid generation device described in claim 1 is configured to select from the plurality of absorption tubes an absorption tube to be fluidly connected to the outlet of the combustion tube by selectively switching a selection port among the plurality of selection ports that is fluidly connected to the common port.

3. A combustion tube for generating a component to be recovered by combusting a sample; A carrier gas supply unit that supplies a carrier gas to the combustion tube and causes the recovery target components generated in the combustion tube to flow out of an outlet of the combustion tube by the carrier gas; an absorption unit including a plurality of absorption tubes each containing an absorption liquid for absorbing and recovering the target components, and an absorption tube selection valve for selecting an absorption tube to be fluidly connected to the outlet of the combustion tube from among the plurality of absorption tubes; a control unit that controls the operation of the absorption unit so that the target components to be recovered generated from the sample introduced into the combustion tube are recovered in a predetermined absorption tube, a switching valve provided between the outlet of the combustion tube and the absorption tube selection valve of the absorption section for selectively fluidly connecting the outlet of the combustion tube to either the absorption section or a drain; the control unit is configured to control the switching valve to fluidly connect the outlet of the combustion tube to the drain while the absorption tube selection valve is operating to switch the absorption tube.

4. A combustion tube for generating a component to be recovered by combusting a sample; A carrier gas supply unit that supplies a carrier gas to the combustion tube and causes the recovery target components generated in the combustion tube to flow out of an outlet of the combustion tube by the carrier gas; an absorption unit including a plurality of absorption tubes each containing an absorption liquid for absorbing and recovering the target components, and an absorption tube selection valve for selecting an absorption tube to be fluidly connected to the outlet of the combustion tube from among the plurality of absorption tubes; a control unit that controls the operation of the absorption unit so that the target components to be recovered generated from the sample introduced into the combustion tube are recovered in a predetermined absorption tube; a sample section having a plurality of sample containers each containing the sample, and a sample selection valve for selecting one of the plurality of sample containers; A recovery liquid generating device configured so that the sample in the sample container selected by the sample selection valve is collected and supplied to the combustion tube.

5. 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, and to absorb the recovery target components generated from the samples in each of the plurality of sample containers into absorption liquids in the separate absorption tubes.

6. The recovery liquid generating device according to claim 1 , wherein the plurality of absorption tubes are mounted on a common rack that is detachably set in the absorption section.

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