Chromatographic system

Abstract

The purpose of the present invention is to easily identify the cause of a state in which analysis cannot be performed in an ion chromatography system. A chromatography system includes: an infusion pump conveying a mobile phase; an autosampler for injecting a sample into the mobile phase; the separation tubular column is used for mutually separating components in the sample; a detector having a detector unit for detecting a component in the eluent flowing through the detector unit; a sensor for measuring a physical quantity related to the chromatography system; an analysis feasibility determination unit that determines, during an analysis preparation time for performing analysis of the sample, whether a detector signal output from the detector is in a non-analyzable state that deviates from a threshold range for a predetermined time period; and a cause specifying unit configured so as to present information pertaining to the sensor for which the measurement value is determined to be unstable to the user as a cause of the non-analyzable state when the sensor for which the measurement value is determined to be unstable exists in the non-analyzable state.

Description

Technical Field

[0001] This invention relates to a chromatography system. Background Technology

[0002] The chromatographic system includes a pump, an autosampler, a separation column, and a detector. In particular, the ion chromatography system includes, in addition to these components, a suppressor, and the detector includes a conductivity detector (see Patent Document 1). The suppressor is installed upstream of the conductivity detector to remove unwanted ions from the eluent from the separation column. By using the suppressor to remove unwanted ions from the eluent, the conductivity of the eluent decreases, the baseline of the conductivity detector signal drops, and highly sensitive ion analysis is possible.

[0003] [Existing technical documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2024-035932 Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] In a chromatographic system, fluctuations in the baseline of the detector signal can affect the analytical results. Therefore, analysis cannot be performed if the detector signal is not stable. It is necessary to wait until the detector signal stabilizes before starting the analysis.

[0008] Analysis cannot be performed for extended periods when the detector signal is unstable, especially in ion chromatography systems. The conductivity of the eluent measured by the conductivity detector varies due to various factors, making it difficult for users to determine the cause of the inability to perform the analysis.

[0009] The present invention was made in view of the aforementioned problems, and its object is to readily determine the cause of a state in which an analysis cannot be performed in a chromatographic system.

[0010] [Technical means to solve the problem]

[0011] The chromatographic system of the present invention includes:

[0012] Infusion pumps deliver the mobile phase;

[0013] An automatic sampler injects a sample into the mobile phase downstream of the infusion pump;

[0014] A separation column is used downstream of the autosampler to separate components in the sample injected into the mobile phase using the autosampler.

[0015] The detector has a detector unit disposed downstream of the separation column for detecting components in the eluent flowing in the detector unit;

[0016] Multiple sensors are used to measure physical quantities related to the chromatographic system;

[0017] The feasibility assessment unit, during the analysis preparation time for performing the analysis of the sample, determines whether the detector signal output from the detector is in an unanalyzable state, deviating from a threshold range set for the detector signal, within a specified time period; and

[0018] The cause determination unit is configured such that, when the analysis feasibility determination unit determines that the state is unanalyzable, if there is a sensor among the plurality of sensors whose measured value is determined to be unstable based on a pre-set benchmark, the unit will provide information related to the sensor whose measured value is determined to be unstable as the cause of the unanalyzable state and prompt the user.

[0019] If multiple analysis-related factors, such as the flow rate of the mobile phase, the temperature of the separation column, the temperature of the detector unit, and room temperature, are all unstable, the detector signal output from the detector in the chromatographic system will be unstable. Particularly in ion chromatography systems, for example, when the suppressor current and voltage change due to power supply or electrode deterioration, and ion exchange between the eluent and suppressor liquid cannot occur properly, the conductivity of the eluent measured by the conductivity detector changes, and the detector signal becomes unstable. Furthermore, when the temperature of the detector unit of the conductivity detector changes by 1°C, the conductivity changes by a few percent; therefore, if the temperature of the detector unit is unstable, the detector signal also becomes unstable. Conversely, if the detector signal of the conductivity detector is stable, it can be said that all analysis-related factors are stable, and therefore, the system can be judged to be in a state where analysis can be performed. In this invention, the stability of the detector signal output from the detector is used to determine whether the system state is unanalyzable, and when the system state is unanalyzable, the stability of the measured values ​​of multiple sensors installed in the system is used to determine the reason for the unanalyzable state and a notification is given to the user.

[0020] [The effects of the invention]

[0021] According to the chromatographic system of the present invention, during the analysis preparation time for performing analysis of a sample, it is determined whether the detector signal output from the detector is in an unanalyzable state that deviates from a threshold range set for the detector signal within a predetermined time period. When the unanalyzable state is determined, if there is a sensor among the plurality of sensors provided in the system whose measured value is determined to be unstable based on a pre-set reference, information related to the sensor whose measured value is determined to be unstable is presented to the user as the cause of the unanalyzable state, so that the user can easily determine the cause of the state in which analysis cannot be performed. Attached Figure Description

[0022] Figure 1 This is a schematic structural diagram illustrating one embodiment of a chromatography system.

[0023] Figure 2 This is a flowchart that schematically represents an example of a series of processes related to the analysis of the described embodiment.

[0024] Figure 3 This is a flowchart illustrating an example of the action to determine the feasibility of the described embodiment.

[0025] Explanation of icon numbers

[0026] 2: Infusion pump

[0027] 4: Automatic Sampler

[0028] 6: Column Oven

[0029] 8: Suppressor

[0030] 10: Conductivity Detector

[0031] 12: Controller

[0032] 14: Processing unit

[0033] 16: Separation String

[0034] 18, 22: Temperature sensors

[0035] 20: Detector Unit

[0036] 24: Feasibility Analysis Department

[0037] 26: Cause Determination Department Detailed Implementation

[0038] Hereinafter, an embodiment of the chromatographic system of the present invention will be described with reference to the accompanying drawings. Here, an ion chromatography system will be described as an example of a chromatographic system.

[0039] like Figure 1 As shown, the ion chromatography system of the embodiment includes an infusion pump 2, an automatic sampler 4, a column oven 6, an inhibitor 8, a conductivity detector 10, a controller 12, and a processing unit 14.

[0040] An automatic sampler 4 is fluidly connected downstream of the infusion pump 2 that delivers the mobile phase. The automatic sampler 4 injects a sample into the mobile phase delivered by the infusion pump 2.

[0041] The column oven 6 houses a separation column 16 and a temperature sensor 18. The separation column 16 is fluidly connected downstream of the autosampler 4, where ionic components in the sample injected into the mobile phase by the autosampler 4 are separated from each other. In addition to the temperature sensor 18, which detects the temperature of the space housing the separation column 16, the column oven 6 also includes a heater and a fan (both omitted from the diagram) for regulating the temperature of the space housing the separation column 16. The output of the heater and fan is controlled to maintain the temperature detected by the temperature sensor 18 at a set temperature.

[0042] The suppressor 8 is fluidly connected downstream of the separation column 16 to remove unwanted ions from the eluent from the separation column 16.

[0043] The conductivity detector 10 includes a detector unit 20, which is connected downstream of the suppressor 8, allows the eluent flowing from the suppressor 8 to pass through, and measures the conductivity of the eluent flowing in the detector unit 20. The conductivity detector 10 independently includes a heater (not shown) for regulating the temperature of the detector unit 20 and a temperature sensor 22 for detecting the temperature of the detector unit 20. The output of the heater is controlled to keep the temperature of the temperature sensor 22 constant. Alternatively, the detector unit 20 and the temperature sensor 22 can be housed together in a common enclosure within the column oven 6.

[0044] The controller 12 manages the operation of the infusion pump 2, the automatic sampler 4, the column oven 6, the suppressor 8, and the conductivity detector 10. The controller 12 can be implemented by electronic circuitry equipped with a central processing unit (CPU) and information storage device.

[0045] The controller 12 includes an analysis feasibility determination unit 24 and a cause determination unit 26. The analysis feasibility determination unit 24 is configured to determine whether the system state is analyzable or unanalyzable during the analysis preparation time for analyzing the next sample. The cause determination unit 26 is configured to determine the cause of the unanalyzable system state and prompt the user if the analysis feasibility determination unit 24 determines that the system state is unanalyzable. The analysis feasibility determination unit 24 and the cause determination unit 26 are functional units obtained by executing a computer program by the CPU of the controller 12. Details regarding the analysis feasibility determination performed by the analysis feasibility determination unit 24 and the cause determination performed by the cause determination unit 26 will be described later.

[0046] The processing unit 14 is a computer device communicatively connected to the controller 12. The user sets analytical conditions on the processing unit 14. The processing unit 14 sends the user-set analytical conditions to the controller 12. Based on the analytical conditions sent from the processing unit 14, the controller 12 manages the operation of the infusion pump 2, the autosampler 4, the column oven 6, the suppressor 8, and the conductivity detector 10. The processing unit 14 also reads and records the detector signal of the conductivity detector 10 through the controller 12, and performs chromatographic preparation, etc.

[0047] and Figure 1 Use together Figure 2 The flowchart illustrates a general flow from the preparation time for analysis of the sample to the execution of the analysis.

[0048] In the ion chromatography system, sample analysis is automatically performed based on the result of the analytical feasibility determination performed by the analytical feasibility determination unit 24. According to preset analytical conditions, the infusion flow rate of the infusion pump 2, the temperature of the column oven 6, the suppressor current or voltage of the suppressor 8, and the temperature of the detector unit 20 of the conductivity detector 10 are controlled respectively. When the analytical preparation time before sample analysis is reached (step 101), the analytical feasibility determination unit 24 of the controller 12 performs an analytical feasibility determination (step 102). In the analytical feasibility determination, the state of the ion chromatography system (system state) is determined to be either an analyzable state (capable of performing sample analysis) or an unanalyzable state (unable to perform sample analysis) (step 103).

[0049] When the analysis feasibility determination unit 24 determines that the system status is unanalyzable (step 103: "No"), the cause determination unit 26 determines the cause of the unanalyzable status and prompts the user (step 104). The analysis feasibility determination performed by the analysis feasibility determination unit 24 (steps 102 and 103) and the cause determination performed by the cause determination unit 26 (step 104) are repeated until the analysis feasibility determination unit 24 determines that the system status is analyzable. When the analysis feasibility determination unit 24 determines that the system status is analyzable (step 103: "Yes"), the controller 12 determines that the analysis preparation is complete, and causes the automatic sampler 4 to perform sample injection and begin sample analysis (step 105).

[0050] Next, with Figure 1 Use together Figure 3 The flowchart explains the feasibility assessment and cause determination of the analysis.

[0051] When the analysis preparation time is reached and analysis preparation begins, the analysis feasibility determination unit 24 begins the analysis feasibility determination. In the analysis feasibility determination, the analysis feasibility determination unit 24 compares the detector signal of the conductivity detector 10 with the upper and lower limits of a preset threshold (step 201), and determines whether the detector signal continuously falls within the threshold range for a specified time (step 202). If the detector signal does not continuously fall within the threshold range for the specified time, i.e., the detector signal is in an unstable state deviating from the threshold range during the specified time period (step 202: No), the analysis feasibility determination unit 24 determines that the system state is unanalyzable (step 203). On the other hand, if the detector signal becomes a stable state continuously falling within the threshold range for the specified time (step 202: Yes), the analysis feasibility determination unit 24 determines that the system state is analyzable (step 207). When the analysis feasibility determination unit 24 determines that the system state is analyzable, the controller 12 determines that analysis preparation is complete and begins sample analysis.

[0052] Furthermore, while the feasibility determination unit 24 determines whether the detector signal falls within a threshold range, the state determination can also be performed by the conductivity detector 10. When the state determination is performed by the conductivity detector 10, if the detector signal is in a stable state, the conductivity detector 10 outputs a stable signal indicating a stable state to the controller 12; if the detector signal is in an unstable state, the conductivity detector 10 outputs an unstable signal indicating an unstable state to the controller 12. Thus, the feasibility determination unit 24 can identify the state of the detector signal.

[0053] In determining the state of the detector signal, the maximum and minimum values ​​of the moving average or the derivative of the moving average of the detector signal (measured conductivity) can be compared with a specified threshold range. The threshold range can be an absolute value (e.g., the difference between the maximum and minimum values ​​is less than 0.01 μS / cm) or a value calculated based on a ratio relative to a reference value (e.g., less than 10% of the detector signal (reference value) when automatic zeroing is applied to the conductivity detector 10).

[0054] If the detector signal is unstable (step 202: No), the analysis feasibility determination unit 24 determines that the system state is unanalyzable (step 203). When the analysis feasibility determination unit 24 determines that the system state is unanalyzable, the cause determination unit 26 confirms the variation state of physical quantities related to the system, such as room temperature, infusion flow rate of infusion pump 2, temperature of separation column 16 detected by temperature sensor 18 of column oven 6, suppressor current or voltage of suppressor 8, and temperature of detector unit 20 detected by temperature sensor 22 of conductivity detector 10, that is, whether each physical quantity is in a stable state or an unstable state based on its respective preset reference (step 205). The determination of whether each physical quantity, such as the temperature of separation column 16, suppressor current or voltage, and temperature of detector unit 20, is in a stable state or an unstable state can be performed by column oven 6, suppressor 8, and conductivity detector 10 respectively, and signals indicating stable and unstable states can be sent to controller 12 respectively. Alternatively, the controller 12 can also determine the variation state of each physical quantity. The algorithm for determining the change state of each physical quantity can be the same as the algorithm for determining the state of the detector signal.

[0055] After confirming the changes in each physical quantity, the cause determination unit 26 determines the reason why the system state is unanalyzable based on the changes in each physical quantity (step 205), and displays the determined reason to the user through an information display device such as a liquid crystal display provided on the controller 12 or a liquid crystal display electrically connected to the processing unit 14 (step 207). For example, if the analysis feasibility determination unit 24 determines that the system state is unanalyzable and the temperature of the detector unit 20 is also unstable, information related to the temperature sensor 22 that measures the temperature of the detector unit 20 is displayed on the information display device, thereby indicating to the user the possibility that the instability of the temperature of the detector unit 20 is the reason for the unanalyzable state. In addition, even if the room temperature is not monitored, although the analysis feasibility determination unit 24 determines that the system state is unanalyzable, if all physical quantities such as the infusion flow rate, the temperature of the column oven 6, the suppressor current or voltage, and the temperature of the detector unit 20 are stable, the factor other than the physical quantity monitored by the sensor (e.g., room temperature) can be determined as the reason for the unanalyzable state, and a display indicating that the reason for the unanalyzable state is that the system is not monitoring the factor (e.g., a display such as "Check air conditioning") can be made.

[0056] The analysis feasibility determination performed by the analysis feasibility determination unit 24 and the cause determination performed by the cause determination unit 26 can be repeated until the analysis feasibility determination unit 24 determines that the system state is capable of analysis and the analysis of the sample begins.

[0057] Furthermore, in the described embodiment, the controller 12 is provided with an analysis feasibility determination unit 24 and a cause determination unit 26, but the present invention is not limited to this form. The analysis feasibility determination unit 24 and the cause determination unit 26 may also be provided in the conductivity detector 10 or the arithmetic processing device 14.

[0058] The embodiments described above are merely one example of implementing the chromatographic system of the present invention. The implementation of the chromatographic system of the present invention is as follows.

[0059] In one embodiment of the chromatography system of the present invention, it includes:

[0060] Infusion pumps deliver the mobile phase;

[0061] An automatic sampler injects a sample into the mobile phase downstream of the infusion pump;

[0062] A separation column is used downstream of the autosampler to separate components in the sample injected into the mobile phase using the autosampler.

[0063] The detector has a detector unit disposed downstream of the separation column for detecting components in the eluent flowing in the detector unit;

[0064] Multiple sensors are used to measure physical quantities related to the chromatographic system;

[0065] The feasibility assessment unit, during the analysis preparation time for performing the analysis of the sample, determines whether the detector signal output from the detector is in an unanalyzable state, deviating from a threshold range set for the detector signal, within a specified time period; and

[0066] The cause determination unit is configured such that, when the analysis feasibility determination unit determines that the state is unanalyzable, if there is a sensor among the plurality of sensors whose measured value is determined to be unstable based on a pre-set benchmark, the unit will provide information related to the sensor whose measured value is determined to be unstable as the cause of the unanalyzable state and prompt the user.

[0067] In one embodiment of the sample [1], the plurality of sensors include at least one of a sensor for measuring room temperature, a sensor for measuring the infusion flow rate of the infusion pump, a sensor for measuring the temperature of the separation column, and a sensor for measuring the temperature of the detector unit.

[0068] In the state sample [2] of the first embodiment, after the analysis feasibility determination unit determines that the state in which the detector signal is within the threshold range is an analytical state that lasts for the predetermined time, the automatic sampler immediately performs sample injection to begin the analysis of the sample. The state sample [2] can be combined with the state sample [1].

[0069] In the state sample [3] of the first embodiment, the cause determination unit is configured such that, even though the analysis feasibility determination unit determines that the state is unanalyzable, if all the measured values ​​of the plurality of sensors are determined to be in a stable state based on the respective preset benchmarks, information related to the plurality of sensors is presented to the user as the cause of the unanalyzable state. The state sample [3] may be combined with the state sample [1] and / or the state sample [2].

[0070] In one embodiment of the sample [4], a suppressor for removing unwanted ionic components from the eluent is included between the separation column and the detector, the detector being a conductivity detector for detecting ionic components in the eluent, and the plurality of sensors including sensors for measuring the current or voltage of the suppressor. The sample [4] may be combined with the samples [1], [2], and / or [3].

Claims

1. A chromatographic system comprising: a delivery pump that delivers a mobile phase; an autosampler that injects a sample into the mobile phase downstream of the delivery pump; a separation column that separates components in the sample injected into the mobile phase with the autosampler from each other downstream of the autosampler; a detector having a detector cell disposed downstream of the separation column that detects components in an eluate flowing in the detector cell; a plurality of sensors that measure physical quantities related to the chromatographic system; an analysis feasibility determination section that determines, during an analysis preparation time for performing analysis of the sample, whether a detector signal output from the detector is in an unanalyzable state in which the detector signal deviates from a threshold range set for the detector signal during a prescribed time; a cause determination section configured to, when the analysis feasibility determination section determines that the unanalyzable state exists, in a case where measured values of the plurality of sensors are determined to be in an unstable state based on respective reference values set in advance, present information related to the sensor whose measured value is determined to be in the unstable state as a cause of the unanalyzable state to a user.

2. The chromatographic system according to claim 1, wherein the plurality of sensors include at least one of a sensor that measures a room temperature, a sensor that measures a delivery flow rate of the delivery pump, a sensor that measures a temperature of the separation column, and a sensor that measures a temperature of the detector cell.

3. The chromatographic system according to claim 1, configured such that, after the analysis feasibility determination section determines that the state in which the detector signal is within the threshold range is an analyzable state that continues for the prescribed time, the autosampler immediately performs injection of the sample to start analysis of the sample.

4. The chromatographic system according to claim 1, wherein the cause determination section is configured to, despite the analysis feasibility determination section determining that the unanalyzable state exists, in a case where measured values of all of the plurality of sensors are determined to be in a stable state based on the respective reference values set in advance, present information related to something other than the plurality of sensors as a cause of the unanalyzable state to the user.

5. The chromatographic system according to claim 1, wherein an eliminator that removes an unnecessary ionic component from the eluate is included between the separation column and the detector, the detector is a conductivity detector that detects ionic components in the eluate, the plurality of sensors include a sensor that measures a current or a voltage of the eliminator. ​

Images