Failure site estimation method and liquid chromatograph

Abstract

A faulty consumable is estimated from among a plurality of consumables in a plunger pump, or a faulty plunger pump is estimated from among a plurality of plunger pumps. A liquid chromatograph (100) is provided with: a double plunger pump (6) having a first plunger pump (9a), a second plunger pump (10a), and a plurality of consumables (11a-14a); a pressure sensor (8a) that detects the pressure of the solvent discharged by the double plunger pump (6); a dispensing unit (2); a separation column (3); and a control unit (16) that estimates a faulty consumable among the plurality of consumables on the basis of a first pressure detected by the pressure sensor (8a) in a first section in which the first plunger pump (9a) discharges the solvent to the flow path (101) and a second pressure detected by the pressure sensor (8a) in a second section in which the second plunger pump (10a) discharges the solvent to the flow path (101).

Description

Technical Field

[0001] The present disclosure relates to a fault location estimation method and a liquid chromatograph. Background Art

[0002] The device used in liquid chromatography analysis is called a liquid chromatograph. Generally speaking, a liquid chromatograph is equipped with a liquid feeding pump, a dispensing unit for introducing a sample into the liquid chromatograph, a separation column, a detector, a waste liquid container, and a system control unit that controls them. In addition, generally speaking, the liquid feeding pump used for the liquid chromatograph has a structure in which two plunger pumps are connected in series. It is called a double plunger pump. The plunger pump (first plunger pump) on the upstream side sucks, compresses, and discharges the solvent. Since it is not possible to feed liquid at a fixed flow rate using only the first plunger pump, another plunger pump (second plunger pump) is connected on the downstream side. The second plunger pump can perform a fixed flow rate of liquid feeding as a whole by performing an action to offset the pulsating flow of the first plunger pump (discharging the solvent when the first plunger pump sucks and compresses the solvent).

[0003] Furthermore, to achieve higher-performance liquid chromatography, high-pressure gradient liquid delivery is often used. This method involves connecting two pairs of dual-plunger pumps in parallel, each delivering a different solvent (e.g., water and an organic solvent), allowing for flexible manipulation of the solvent mixing ratio. Therefore, four plunger pumps are required to perform high-pressure gradient liquid delivery.

[0004] Each plunger pump is equipped with a plunger seal to prevent fluid leakage from the plunger. Furthermore, check valves are installed on the inlet and outlet sides of the upstream plunger pump of the dual plunger pump to prevent backflow. Plunger seals and check valves are consumable parts and deteriorate due to wear and other factors.

[0005] To verify that liquid chromatography analysis is being performed correctly, a known internal standard substance is sometimes mixed with the sample separately from the substance being analyzed. This is generally referred to as the internal standard method. By confirming the detection intensity and detection time of the internal standard substance, it is confirmed that the instrument is functioning properly.

[0006] In commonly known examples, abnormalities in the liquid chromatograph are detected by monitoring the signals of a pressure gauge installed in the liquid delivery pump and an internal standard substance, thereby inferring the location of the fault. Furthermore, if the fault is inferred to be in the liquid delivery pump, consumable parts are often replaced. Patent Document 1 discloses a method for detecting abnormalities in each unit using a flow meter installed in the liquid delivery pump and a light meter installed in the detection unit. Patent Document 2 discloses a method for detecting pressure pulsations using a pressure gauge installed in the liquid delivery pump and stopping the device.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2017-156093

[0010] Patent Document 2: International Publication No. 2020 / 183774 Summary of the Invention

[0011] Problems to be solved by the invention

[0012] Typically, when the fault is suspected to be in the liquid feed pump, consumable parts are often replaced. However, since it's unknown exactly where the fault is within the liquid feed pump, all consumable parts are often replaced when a suspected liquid feed pump failure occurs, leading to increased component costs. In particular, in the case of a liquid feed pump with a high-pressure gradient function, since there are four plunger pumps, replacing all consumable parts increases component costs and the time required for replacement.

[0013] Therefore, an object of the present disclosure is to estimate a failed consumable from among a plurality of consumables in a plunger pump, or to estimate a failed plunger pump from among a plurality of plunger pumps.

[0014] Means for solving problems

[0015] The fault location inference method disclosed herein is a fault location inference method for inferring the fault location of a liquid chromatograph, and comprises the following steps: discharging a solvent into a flow path by a dual-plunger pump having a first plunger pump, a second plunger pump arranged on the downstream side of the first plunger pump, and a plurality of consumables involved in the discharge of the solvent; introducing a sample into the flow path; detecting the pressure of the solvent discharged by the dual-plunger pump; separating the sample into components by a separation column; detecting the components separated by the separation column; and inferring a faulty consumable among a plurality of consumables based on a first pressure detected in a first interval in which the first plunger pump discharges the solvent into the flow path, and a second pressure detected in a second interval in which the second plunger pump discharges the solvent into the flow path.

[0016] In addition, the liquid chromatograph disclosed in the present invention comprises: a double-plunger pump, which has a first plunger pump, a second plunger pump arranged on the downstream side of the first plunger pump, and a plurality of consumables involved in the discharge of the solvent; a pressure sensor, which detects the pressure of the solvent discharged by the double-plunger pump; an injection section, which introduces the sample into the flow path; a separation column, which is connected to the downstream side of the injection section and separates the sample into components; a detection section, which detects the components separated by the separation column; and a control section, which infers a faulty consumable among the plurality of consumables based on a first pressure detected by the pressure sensor in a first section where the first plunger pump discharges the solvent into the flow path, and a second pressure detected by the pressure sensor in a second section where the second plunger pump discharges the solvent into the flow path.

[0017] The fault location inference method disclosed herein is a fault location inference method for inferring the fault location of a liquid chromatograph, and comprises the following steps: mixing a plurality of solvents and discharging them into a flow path through a plurality of plunger pumps; introducing a sample into the flow path; separating the sample into components through a separation column; detecting the components separated by the separation column; when detecting the components of the sample, obtaining the retention time of an internal standard substance supplied to the flow path, and determining whether the retention time is advanced or delayed compared to a specified value; and inferring a faulty plunger pump among the plurality of plunger pumps based on the determination result of the retention time.

[0018] In addition, the liquid chromatograph disclosed in the present invention comprises: a plurality of plunger pumps that mix a plurality of solvents and discharge them into a flow path; a dispensing section that introduces a sample into the flow path; a separation column that is connected to the downstream side of the dispensing section and separates the sample into components; a detection section that detects the components separated by the separation column; and a control section that, when detecting the components of the sample, obtains the retention time of an internal standard substance supplied to the flow path, determines whether the retention time is advanced or delayed compared to a specified value, and infers a faulty plunger pump among the plurality of plunger pumps based on the determination result of the retention time.

[0019] Effects of the Invention

[0020] According to the present disclosure, it is possible to infer a faulty consumable from among multiple consumables within a plunger pump, or to infer a faulty plunger pump from among multiple plunger pumps. As a result, it is expected that component costs will be reduced and the time required for recovery operations will be shortened. Other issues, structures, and effects beyond those described above will become clear through the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram showing the structure of the liquid chromatograph of Example 1.

[0022] Figure 2 This is a graph showing the displacement of each plunger when the solvent is normally delivered by the first double-plunger pump.

[0023] Figure 3 This is a diagram showing the transition between sections during normal liquid feeding of the first and second double-plunger pumps.

[0024] Figure 4 This is an example of the measurement results when a sample is measured using the liquid chromatograph of Example 1.

[0025] Figure 5 This is a diagram showing a reference table held by the liquid chromatograph of Example 1.

[0026] Figure 6 This is a flow chart for estimating the failure location of the liquid feeding pump using the liquid chromatograph of Example 1.

[0027] Figure 7This is an example of abnormal measurement results when a sample is measured using the liquid chromatograph of Example 1.

[0028] Figure 8 This is actual data from the pressure sensor included in the first twin-plunger pump.

[0029] Figure 9 It is a schematic diagram showing the structure of the liquid chromatograph of Example 2.

[0030] Figure 10 This is a flow chart for estimating the fault location of a liquid feeding pump using the liquid chromatograph of Example 2. DETAILED DESCRIPTION

[0031] In the following embodiments, the structural elements (including element steps, etc.) are not necessarily essential unless otherwise specified or unless they are clearly considered to be essential in principle.

[0032] (Example 1)

[0033] <Structure Example of Liquid Feeding Pump and Liquid Chromatograph>

[0034] Figure 1 Schematic diagram showing the structure of the liquid chromatograph of Example 1. Figure 1 As shown, the liquid chromatograph 100 includes a first double-plunger pump 6, a second double-plunger pump 7, a dispensing section 2, a separation column 3, a detection section 4, a waste liquid container 5, and a control section 16 that controls them. The dispensing section 2 introduces the sample 1 into the liquid chromatograph 100 (flow path 101). The separation column 3 is connected to the downstream side of the dispensing section 2 and separates the sample 1 into various components. The detection section 4 detects the various components separated by the separation column 3 and produces a chromatogram. The waste liquid container 5 is a container for discarding the solvent and sample after the measurement. As for the dispensing section 2, the separation column 3, the detection section 4 and the waste liquid container 5, components commonly used in liquid chromatographs can be used, so their detailed structures are not particularly described.

[0035] The liquid chromatograph 100 of Example 1 performs liquid chromatography analysis using a liquid delivery method known as high-pressure gradient delivery. Therefore, in the liquid chromatograph 100, multiple plunger pumps (a first double plunger pump 6 and a second double plunger pump 7) connected in parallel mix multiple solvents and discharge them into the flow path. For example, the first double plunger pump 6 discharges water from a solvent bottle 15a, while the second double plunger pump 7 discharges an organic solvent (e.g., methanol) from a solvent bottle 15b.

[0036] <First Double-Plunger Pump 6>

[0037] The first double plunger pump 6 includes a pressure sensor 8a, a first plunger pump 9a, a second plunger pump 10a, and a plurality of consumables for discharging the solvent. The first plunger pump 9a and the second plunger pump 10a are connected in series, with the first plunger pump 9a being located upstream and the second plunger pump 10a being located downstream.

[0038] The pressure sensor 8a is provided downstream of the second plunger pump 10a and measures the pressure (discharge pressure) of the solvent (liquid) discharged from the second plunger pump 10a and outputs the pressure value to the control unit 16.

[0039] The control unit 16 supplies command values ​​to the first plunger pump 9 a and the second plunger pump 10 a based on the discharge pressure measured by the pressure sensor 8 a and a predetermined operation sequence to control the operations thereof.

[0040] The first plunger pump 9a includes a first check valve 13a, a second check valve 14a, and a first seal 11a. The first check valve 13a is located in the flow path of the first plunger pump 9a's suction port, while the second check valve 14a is located in the flow path of the first plunger pump 9a's discharge port. The first and second check valves 13a, 14a restrict the flow of solvent. The first seal 11a prevents leakage from the first plunger pump 9a.

[0041] The second plunger pump 10a includes a second seal 12a. The second seal 12a prevents liquid leakage from the second plunger pump 10a.

[0042] The solvent (for example, water) contained in the solvent bottle 15 a is squeezed out by the first plunger pump 9 a and the second plunger pump 10 a and supplied to the downstream dispensing unit 2 and the separation column 3 .

[0043] <Second double plunger pump 7>

[0044] The second double-plunger pump 7 has the same structure as the first double-plunger pump 6 and includes a pressure sensor 8b, a first plunger pump 9b, a second plunger pump 10b, a first seal 11b, a second seal 12b, a first check valve 13b, and a second check valve 14b. The solvent (e.g., methanol) contained in a solvent bottle 15b is extruded by the first and second plunger pumps 9b, 10b and supplied to the downstream dispensing unit 2 and separation column 3. A detailed description of the second double-plunger pump 7 is omitted, as it is similar to the first double-plunger pump 6.

[0045] The solvent discharged from the first double-plunger pump 6 and the solvent discharged from the second double-plunger pump 7 merge at the merging portion 102 and are mixed at a desired concentration ratio. Thus, in the liquid chromatograph 100 of Example 1, the components in the sample 1 can be separated and eluted while continuously changing the concentration ratio of the eluent (water, methanol).

[0046] In this specification, the "lower limit point" refers to the position at which the plunger pump (9a, 9b, 10a, 10b) has descended the most within the range of movement within the pressurized chamber. On the other hand, the "upper limit point" refers to the position at which the plunger pump (9a, 9b, 10a, 10b) has ascended the most within the range of movement within the pressurized chamber. Furthermore, the "ascending" movement of the plunger pump (9a, 9b, 10a, 10b) indicates movement in the direction of compressing or discharging the solvent within the pressurized chamber, while the "descending" movement of the plunger indicates movement in the direction of drawing the solvent into the pressurized chamber.

[0047] The solvent contained in the solvent bottle 15a is squeezed out by the first plunger pump 9a and the second plunger pump 10a of the first double plunger pump 6 and supplied to the dispensing part 2. In addition, the solvent contained in the solvent bottle 15b is squeezed out by the first plunger pump 9b and the second plunger pump 10b of the second double plunger pump 7 and supplied to the dispensing part 2. The sample 1 to be analyzed is injected into the solvent supplied to the dispensing part 2. The solvent injected with the sample 1 is introduced into the separation column 3 and separated according to the components. Then, the absorbance, fluorescence intensity, refractive index, etc. corresponding to the sample components are detected by the detection part 4. The separation column 3 is a reverse phase column. The separation column 3 can also be a normal phase column. The separation column 3 is filled with microparticles, and the fluid resistance when the solvent flows in the gaps between the microparticles generates a load pressure of tens of MPa to over 100 MPa in the double plunger pumps (6, 7). The magnitude of this load pressure varies depending on the diameter of the separation column 3 and the flow rate.

[0048] <Control Unit 16>

[0049] The control unit 16 has a processor 17, a main storage unit 18, an auxiliary storage unit 19, and an interface 20. The processor 17 is a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a DSP (Digital Signal Processor), an ASIC, etc. The main storage unit 18 is a DRAM (Dynamic Random Access Memory), etc., and is used as a work area for the processor 17. The auxiliary storage unit 19 is an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof, etc., and stores various programs and various data. The interface 20 is a device controller that controls the operation of the first double-plunger pump 6, the second double-plunger pump 7, etc. connected to the control unit 16, a monitor interface that outputs image signals to the display unit 21, and a network controller that performs communication control.

[0050] For example, the auxiliary storage unit 19 stores a program for estimating a failed dual-plunger pump from a plurality of dual-plunger pumps (6, 7) and estimating a failed consumable from a plurality of consumables in the estimated failed dual-plunger pump. In addition, the auxiliary storage unit 19 stores a reference table 500 (reference table 500) to be referred to when executing the above program. Figure 5 ) In addition, the reference table 500 may be stored in the auxiliary storage unit 19 inside the control unit 16 or in a storage unit outside the control unit 16.

[0051] <Method of delivering liquid>

[0052] The following describes an overview of the liquid feeding method when the first double-plunger pump 6 of Example 1 is used to normally feed the solvent. Here, "normal liquid feeding" refers to the liquid feeding method when the solvent discharged from the first double-plunger pump 6 flows to the dispensing unit 2, the separation column 3, and the detection unit 4 to analyze the sample 1. Figure 1 The first and second double plunger pumps 6 and 7 shown have the same device structure, so the description of the liquid feeding method of the second double plunger pump 7 is omitted. In addition, the second double plunger pump 7 performs the same operation as the first double plunger pump 6 with a delay of half a cycle.

[0053] Figure 2 This is a graph showing the displacement of each plunger when the first twin-plunger pump 6 normally delivers the solvent. Figure 2 The horizontal axis of both graphs represents time, and the vertical axis represents, from top to bottom, the displacement of the first plunger pump 9a and the displacement of the second plunger pump 10a. The displacement of the first plunger pump 9a and the displacement of the second plunger pump 10a is defined as positive in the ascending direction and negative in the descending direction. During normal liquid delivery, both the first plunger pump 9a and the second plunger pump 10a operate with the lower limit point as the reference.

[0054] During normal liquid delivery, both the first plunger pump 9a and the second plunger pump 10a perform periodic operations. Figure 2 , two cycles are shown. Drive cycle a consists of four intervals b, c, d, and e, which repeat in sequence. The length of drive cycle a is, for example, 2 seconds, 4 seconds, or 6 seconds. Each interval is described below.

[0055] Section b is the independent liquid delivery section by the second plunger pump 10a. During this section, the second plunger pump 10a delivers the liquid delivery volume specified by the device user. The first plunger pump 9a moves to the lower limit point and then stops until the end of section b. Although the first plunger pump 9a is displaced in the negative direction, the second check valve 14a closes the flow path, so the operation of the first plunger pump 9a does not affect the discharge flow rate.

[0056] Interval c is called the compression interval. In this interval, the second plunger pump 10a discharges the liquid delivery volume specified by the user of the device. The control unit 16 calls out the stored compression rate parameters and calculates the pressure value received from the pressure sensor 8a and the compression amount of the solvent (plunger displacement) required for compression by the first plunger pump 9a. Afterwards, under the control of the control unit 16, the first plunger pump 9a moves the calculated compression amount in the positive direction. The second check valve 14a is closed until the pressure in the pressurization chamber of the first plunger pump 9a exceeds the discharge pressure, so the action of the first plunger pump 9a will not affect the discharge flow rate.

[0057] Interval d is called the crossover liquid delivery interval. During this interval, the second plunger pump 10a moves to its lower limit. The first plunger pump 9a moves in the positive direction and delivers a flow rate that is the sum of the suction flow rate generated by the second plunger pump 10a moving in the negative direction and the flow rate specified by the device user. Thus, the first dual-plunger pump 6 as a whole delivers the liquid delivery volume specified by the device user.

[0058] Section e is called the single liquid delivery section by the first plunger pump 9a. In this section, the first plunger pump 9a delivers the liquid delivery volume specified by the device user. The second plunger pump 10a stops until the end of section e.

[0059] After the individual liquid feeding interval e by the first plunger pump 9a is completed, the process shifts to the interval b and the same cycle operation is repeated.

[0060] In the above sections b through e, it is important to note that the second plunger pump 10a primarily delivers liquid in sections b and c, while the first plunger pump 9a primarily delivers liquid in sections d and e. It is also important to note that the check valves opened and closed in each section are different.

[0061] For example, if the first seal 11a of the first plunger pump 9a fails, leakage occurs from the first plunger pump 9a, rendering liquid delivery by the first plunger pump 9a impossible. Consequently, during intervals d and e, the delivery volume of the dual plunger pump decreases, and the delivery pressure drops. Subsequently, when the system transitions to interval b, the second check valve 14a closes the flow path, allowing the second plunger pump 10a to take over delivery. This restores the delivery volume of the dual plunger pump 6 to the flow rate specified by the device user, and the delivery pressure also returns to its normal value.

[0062] Similarly, if, for example, the first check valve 13a of the first plunger pump 9a fails, reverse flow occurs upstream from the first plunger pump 9a, preventing delivery of liquid by the first plunger pump 9a. Consequently, during intervals d and e, the delivery volume of the dual plunger pump 6 decreases, and the delivery pressure drops. Subsequently, when the system transitions to interval b, the second check valve 14a closes the flow path, allowing the second plunger pump 10a to take over delivery. This restores the delivery volume of the dual plunger pump 6 to the flow rate specified by the device user, and the delivery pressure also returns to its normal value.

[0063] For example, if the second check valve 14a of the first plunger pump 9a fails, backflow occurs from the downstream second plunger pump 10a to the upstream first plunger pump 9a, rendering the second plunger pump 10a unable to deliver liquid. Consequently, in intervals b and c, the delivery volume of the dual plunger pump 6 decreases, and the delivery pressure drops. Later, when the system shifts to interval d, the plunger pump responsible for delivering liquid shifts from the second plunger pump 10a to the first plunger pump 9a. While the first plunger pump 9a is delivering liquid, the second check valve 14a remains open. Therefore, even if the second check valve 14a fails and loses its valve function, normal delivery is possible. Consequently, as the delivery volume of the dual plunger pump 6 returns to the flow rate specified by the device user, the delivery pressure also returns to its normal value.

[0064] For example, if the second seal 12a of the second plunger pump 10a fails, the liquid delivery flow rate and pressure will decrease in all sections from section b to section e. This is because the liquid delivered by the first plunger pump 9a also passes through the cylinder of the second plunger pump 10a, so leakage will occur regardless of the timing of the liquid delivery.

[0065] In this way, by confirming in which section of the section b to the section e the pressure value decreases, it is possible to identify a component with a high possibility of failure.

[0066] Figure 3 This is a diagram showing the shift of intervals during normal liquid delivery of the first double-plunger pump 6 and the second double-plunger pump 7. The two double-plunger pumps 6 and 7 operate with the drive cycle a staggered by half a cycle. That is, when the first double-plunger pump 6 is in intervals b and c, the second double-plunger pump 7 is in intervals d and e. Here, the period when the first double-plunger pump 6 is in intervals b and c, and the period when the second double-plunger pump 7 is in intervals d and e is referred to as interval f (first interval). In addition, conversely, the period when the first double-plunger pump 6 is in intervals d and e, and the period when the second double-plunger pump 7 is in intervals b and c is referred to as interval g (second interval).

[0067] <Internal Standard Method>

[0068] Figure 4This is an example of measurement results when a sample is measured using the liquid chromatograph of Example 1. The horizontal axis represents the elapsed time from the start of measurement, and the vertical axis represents the detection value in the detection unit 4 . Figure 4 There are three peaks in the graph, which are, from the left, peaks derived from an internal standard substance (Internal Standard), target substance A, and target substance B. The device user uses the liquid chromatograph 100 for the purpose of measuring target substances A and B.

[0069] The user of the device mixes a known internal standard substance at a known concentration into the sample to be measured and measures the sample. Figure 4 As shown in FIG, a detection peak originating from the internal standard substance appears. With respect to the detection peak originating from the internal standard substance, the peak retention time and peak height are stored in the control unit 16 in advance, and by comparing with the values, it is confirmed whether the liquid chromatograph 100 is operating normally. For example, in Figure 4 In the example, the internal standard substance retention time is approximately 26 seconds. This value is checked to ensure the normal operation of the device by checking whether it falls within a predetermined time range stored in the control unit 16, for example, 25 to 27 seconds. If it does not fall within the predetermined time range, the device user is notified of the device abnormality.

[0070] The retention time of the internal standard substance varies depending on the composition of the separation column 3 and the solvent ratio of the high-pressure gradient liquid delivery by the dual plunger pumps 6 and 7, and the predetermined range of time is determined by prior experiments.

[0071] For example, a reverse phase column may be used as the separation column 3, with water delivered from the first double plunger pump 6 and methanol delivered from the second double plunger pump 7. Depending on the target substance to be measured, the internal standard substance and the delivery ratio of water to methanol may vary. These are determined by the user of the device through prior research and experimentation.

[0072] Generally speaking, reversed-phase columns have the following characteristics: increasing the ratio of an organic solvent such as methanol increases the retention time, while increasing the ratio of water increases the retention time. For example, when measuring an internal standard substance with a mixture ratio of 50% water and 50% methanol, the retention time is 26 seconds. However, if the ratio is 60% water and 40% methanol, the retention time is shortened to 20 seconds. Thus, the retention time of the internal standard substance varies depending on the characteristics of the separation column 3 and the ratio of the solvents being fed.

[0073] In the same example, if the internal standard substance holding time, which used to be approximately 26 seconds, is shortened to approximately 20 seconds, the expected delivery rate of the dual-plunger pump for water delivery will decrease, and the methanol delivery ratio will increase. Conversely, if the internal standard substance holding time is delayed to approximately 30 seconds, the expected delivery rate of the dual-plunger pump for methanol delivery will decrease, and the water delivery ratio will increase.

[0074] Thus, by focusing on the retention time of the internal standard substance, it is possible to identify a double-plunger pump with a reduced liquid delivery volume.

[0075] <Reference Table>

[0076] Figure 5 This figure shows the reference table stored in the liquid chromatograph of Example 1. Here, reference table 500 stored in auxiliary storage unit 19 of control unit 16 is described. Reference table 500 includes information about the section where the pressure anomaly occurred, information about whether the retention time of the internal standard substance is earlier or later than the specified range, and information about malfunctioning consumables. Control unit 16 refers to reference table 500 to infer the malfunctioning consumable.

[0077] Reference table 500 is a data table assuming that separation column 3 is a reversed-phase column, dual plunger pump 6 discharges water, and dual plunger pump 7 discharges methanol. Based on reference table 500, if the retention time of the internal standard substance exceeds the specified time range, it is determined that dual plunger pump 6 has failed. If the retention time of the internal standard substance exceeds the specified time range, it is determined that dual plunger pump 7 has failed.

[0078] Furthermore, according to reference table 500, if the internal standard substance retention time exceeds the specified time range and the pressure anomaly occurs only in interval f, it is determined that the second check valve 14a of the dual plunger pump 6 is faulty. Furthermore, if the internal standard substance retention time exceeds the specified time range and the pressure anomaly occurs only in interval g, it is determined that the first seal 11a or first check valve 13a of the dual plunger pump 6 is faulty. Furthermore, if the internal standard substance retention time exceeds the specified time range and the pressure anomaly occurs only in interval f and interval g, it is determined that the second seal 12a of the dual plunger pump 6 is faulty.

[0079] Furthermore, according to reference table 500, if the holding time of the internal standard substance exceeds the specified time range and the pressure anomaly occurs only in interval f, it is determined that the first seal 11b or first check valve 13b of the dual plunger pump 7 is faulty. Furthermore, if the holding time of the internal standard substance exceeds the specified time range and the pressure anomaly occurs only in interval g, it is determined that the second check valve 14b of the dual plunger pump 7 is faulty. Furthermore, if the holding time of the internal standard substance exceeds the specified time range and the pressure anomaly occurs only in interval f and interval g, it is determined that the second seal 12b of the dual plunger pump 7 is faulty.

[0080] <Fault Location Estimation>

[0081] Figure 6 This is a flow chart for estimating the fault location of the liquid delivery pump (the first double plunger pump 6 and the second double plunger pump 7 are collectively referred to as the liquid delivery pump) using the liquid chromatograph of Example 1. For example, Figure 6 Each step of the flowchart is performed by the processor 17 of the control unit 16 executing a program for estimating a malfunctioning consumable.

[0082] Here, a reverse phase column was used as the separation column 3 , water was fed from a first double plunger pump 6 , and methanol was fed from a second double plunger pump 7 .

[0083] <Example of Fault Location Estimation>

[0084] exist Figure 1 In the configuration of the liquid chromatograph shown, an example will be described in which a sample 1 is actually measured and an abnormality is found.

[0085] Figure 7 This is an example of the measurement result of abnormality when measuring a sample using the liquid chromatograph of Example 1. The horizontal axis is the elapsed time from the start of measurement, and the vertical axis is the detection value in the detection unit 4. Figure 4 The specimens shown are identical to the specimens shown.

[0086] according to Figure 6 As shown in the flowchart, the control unit 16 first performs an internal standard substance measurement (step S601). Specifically, the first double-plunger pump 6 and the second double-plunger pump 7 discharge the solvent into the flow path 101, and the sample 1 and the internal standard substance are introduced into the flow path 101. Then, the pressure sensors 8a and 8b detect the pressure of the solvent discharged by the first double-plunger pump 6 and the second double-plunger pump 7. The separation column 3 then separates the sample 1 into its components, and the detection unit 4 detects the components separated by the separation column 3. At this time, the components of the sample 1 and the internal standard substance are measured.

[0087] When the internal standard substance measurement is completed, the control unit 16 confirms the internal standard substance measurement results (step S602). Confirmation of the internal standard substance measurement results is to confirm whether the retention time, peak height, peak area, half-value width, or a combination thereof is within a predetermined range stored in the control unit 16. The retention time, peak height, peak area, half-value width, or a combination thereof of the internal standard substance is referred to as a characteristic quantity of the internal standard substance.

[0088] If the characteristic quantity of the internal standard substance is normal (step S603: No), the control unit 16 ends this flowchart (step S604). On the other hand, if the characteristic quantity of the internal standard substance is abnormal (step S603: Yes), the control unit 16 determines whether there is an abnormality in the holding time (step S605).

[0089] exist Figure 7 In the measurement results shown, the peak time of the internal standard substance is about 23 seconds, which is relatively Figure 4 The peak time (approximately 26 seconds) of the internal standard substance under normal conditions is advanced. In this embodiment, for example, the normal range of the holding time is 25 seconds to 27 seconds. In this case, the control unit 16 determines that the measurement result of the internal standard substance (peak time (approximately 23 seconds)) is abnormal (step S605: Yes) and executes the processing of step S607.

[0090] On the other hand, when the control unit 16 determines that the measurement result of the internal standard substance is not abnormal (step S605 : No), it suspects a failure other than the liquid feeding pump (step S606 ) and ends this flowchart (step S604 ).

[0091] The control unit 16 confirms that the change in the holding time is not within the normal range (step S607). Figure 7 In the example, the holding time is advanced compared to the specified value (step S607: advanced), so the control unit 16 refers to the reference table 500 and determines that the first double-plunger pump 6 has failed (step S608). On the other hand, when the holding time is delayed compared to the specified value (step S607: delayed), the control unit 16 refers to the reference table 500 and determines that the second double-plunger pump 7 has failed (step S609). It is believed that when a reverse phase column is used as the separation column 3 and the holding time is advanced, the water delivery rate decreases and the methanol delivery rate increases. Therefore, the most suspected failure is the first double-plunger pump 6 that delivers water. In addition, when the holding time is delayed, it is believed that the methanol delivery rate decreases and the water delivery rate increases. Therefore, the most suspected failure is the second double-plunger pump 7 that delivers methanol.

[0092] After determining that the first tandem plunger pump 6 has failed (step S608 ), the control unit 16 checks the value of the pressure sensor 8 a included in the first tandem plunger pump 6 and identifies the section where the pressure is abnormal (step S610 ). Figure 8 This is actual data from the pressure sensor 8a included in the first twin-plunger pump 6. The horizontal axis represents time, and the vertical axis represents pressure value.

[0093] according to Figure 8 , it can be confirmed that the pressure (second pressure) decreases in interval f and the pressure (first pressure) increases in interval g. This means that the liquid delivery volume of the second plunger pump 10a decreases as described above, and the liquid delivery volume of the first plunger pump 9a is normal. Figure 8 In the example of FIG, the control unit 16 confirms the pressure drop in the interval f, and therefore suspects that the second check valve 14a of the first twin-plunger pump 6 is faulty (step S612).

[0094] Furthermore, if it is confirmed that the pressure (second pressure) increases during interval f and decreases during interval g (first pressure), it can be determined that the liquid delivery rate of the first plunger pump 9a is reduced, while the liquid delivery rate of the second plunger pump 10a is normal. Therefore, the control unit 16 confirms the pressure drop during interval g and suspects that the first seal 11a or the first check valve 13a of the first twin-plunger pump 6 is faulty (step S613).

[0095] Furthermore, if a pressure drop is confirmed across the entire interval, it can be determined that the overall delivery volume of the first twin-plunger pump 6 has decreased. Therefore, since the control unit 16 has confirmed a pressure drop across the entire interval, it is suspected that the second seal 12a of the first twin-plunger pump 6 has failed (step S614).

[0096] On the other hand, after determining that the second tandem plunger pump 7 has failed (step S609), the control unit 16 checks the value of the pressure sensor 8b included in the second tandem plunger pump 7 and confirms the section of abnormal pressure (step S611).

[0097] If it is confirmed that the pressure is decreasing during interval f and increasing during interval g, it can be determined that the liquid delivery rate of the first plunger pump 9b has decreased, while the liquid delivery rate of the second plunger pump 10b is normal. Therefore, the control unit 16 confirms the pressure drop during interval f and suspects that the first seal 11b or the first check valve 13b of the second tandem plunger pump 7 has failed (step S615).

[0098] Furthermore, if it is confirmed that the pressure is rising in interval f and falling in interval g, it can be determined that the liquid delivery rate of the second plunger pump 10b is reduced, while the liquid delivery rate of the first plunger pump 9b is normal. Therefore, the control unit 16 confirms the pressure drop in interval g and suspects that the second check valve 14a of the second tandem plunger pump 7 is faulty (step S616).

[0099] If a pressure drop is confirmed throughout the entire interval, it can be determined that the overall delivery volume of the second twin-plunger pump 7 has decreased. Therefore, the control unit 16 confirms the pressure drop throughout the entire interval and suspects that the second seal 12b of the second twin-plunger pump 7 has failed (step S617).

[0100] In addition, if the section with abnormal pressure cannot be confirmed in steps S610 and S611, it is determined that there is no fault location and this flowchart ends (step S604).

[0101] In the above-mentioned first embodiment, it is possible to determine whether the first twin-plunger pump 6 or the second twin-plunger pump 7 has failed based on the change in the retention time of the internal standard substance.

[0102] In the above-mentioned embodiment 1, the fault location of the consumables (first seal 11a, second seal 12a, first check valve 13a, second check valve 14a, first seal 11b, second seal 12b, first check valve 13b, second check valve 14b) can be determined from the interval where the pressure abnormality occurs.

[0103] <Method for Estimating a Faulty Consumable Item from Multiple Consumable Items in a Plunger Pump>

[0104] As described above, the method for estimating a failed consumable from among a plurality of consumables in a plunger pump in the liquid chromatograph of Example 1 (failure location estimation method) includes the following steps:

[0105] The solvent is discharged to the flow path 101 by the first double-plunger pump 6 and the second double-plunger pump 7; the sample 1 is introduced into the flow path 101 through the dispensing unit 2 (step S601);

[0106] Detecting the pressure of the solvent discharged by the first double-plunger pump 6 and the second double-plunger pump 7 (step S601); separating the sample 1 into components by the separation column 3 (step S601); and

[0107] Based on the first pressure detected in the first section (section g) in which the first plunger pump 9a (or 9b) discharges the solvent into the flow path, and the second pressure detected in the second section (section f) in which the second plunger pump 10a (or 10b) discharges the solvent into the flow path, a faulty consumable among multiple consumables is inferred (steps S610 to S617).

[0108] In addition, the fault location estimation method also has the following steps:

[0109] When detecting the components of the sample 1, the retention time of the internal standard substance supplied to the flow path 101 is obtained, and it is determined whether the retention time is advanced or delayed compared to the specified value (step S607); and

[0110] Based on the determination result of the retention time, the type of separation column 3 (reverse phase column, normal phase column) and the type of solvent (water, methanol), the faulty dual plunger pump among the multiple dual plunger pumps (first dual plunger pump 6 and second dual plunger pump 7) is estimated (steps S607 to S609).

[0111] The following steps are involved in diagnosing the above-mentioned faulty consumables:

[0112] If the first pressure is not abnormal and the second pressure is abnormal, it is inferred that the second check valve is faulty (steps S612 and S616);

[0113] If the first pressure is abnormal and the second pressure is not abnormal, it is inferred that the first seal or the first check valve is faulty (step S613, step S615);

[0114] When the first pressure and the second pressure are abnormal, it is estimated that the second seal has failed (steps S614 and S617 ).

[0115] <Method for Estimating a Faulty Plunger Pump from Multiple Plunger Pumps>

[0116] The method for estimating a failed plunger pump from among a plurality of plunger pumps in a liquid chromatograph (failure location estimation method) of Example 1 has the following features as described above:

[0117] A plurality of solvents are mixed and discharged to the flow path 101 by a plurality of double plunger pumps (6, 7) (step S601);

[0118] The sample 1 is introduced into the flow channel 101 via the dispensing unit 2 (step S601);

[0119] The sample 1 is separated into components by the separation column 3 (step S601);

[0120] The components separated by the separation column 3 are detected by the detection unit 4 (step S601);

[0121] When detecting the components of the sample 1, the retention time of the internal standard substance supplied to the flow path 101 is obtained, and it is determined whether the retention time is advanced or delayed compared to the specified value (step S607); and

[0122] Based on the determination result of the holding time, a faulty plunger pump among a plurality of dual plunger pumps (6, 7) is estimated.

[0123] The steps to diagnose the above-mentioned faulty plunger pump include the following:

[0124] Based on the determination result of the retention time, the type of the separation column 3 (reverse phase column, normal phase column) and the type of the solvent (water, methanol), the faulty plunger pump among the plurality of double plunger pumps (6, 7) is estimated.

[0125] When the type of separation column to be used is determined, the above-mentioned information on the type of separation column 3 is unnecessary. When the type of solvent to be used is determined, the above-mentioned information on the type of solvent is unnecessary.

[0126] (Example 2)

[0127] In Example 1, the Figure 1 The example shown is a liquid chromatograph having a high-pressure gradient liquid feeding function. However, the present invention can also be applied to a liquid chromatograph not having a high-pressure gradient liquid feeding function.

[0128] For example, Figure 9 The following describes a liquid chromatograph 900 comprising a single double-plunger pump 906. In this configuration, there is only one double-plunger pump 906, and only pre-prepared solvents are delivered. The liquid chromatograph 900 of Example 2 includes a dispensing unit 902 for introducing a sample 901 into the liquid chromatograph 900, a separation column 903, a detection unit 904, a waste liquid container 905, the double-plunger pump 906, and a control unit 916.

[0129] The dual plunger pump 906 also includes a pressure sensor 908, a first plunger pump 909, a second plunger pump 910, a first seal 911, a second seal 912, a first check valve 913, a second check valve 914, and a solvent bottle 915. Details of the various components of the dual plunger pump 906 are the same as those in Example 1, and therefore their description will be omitted.

[0130] Figure 10 This is a flow chart for estimating the fault location of a liquid feeding pump using the liquid chromatograph of Example 2. Figure 10 The processing of steps S1001 to S1004 is the same as that of embodiment 1. Figure 6 The processing of steps S601 to S604 is the same, so their description is omitted.

[0131] In Example 2, the control unit 916 checks for abnormality in the liquid supply pressure (step S1005). If the liquid supply pressure pulsates or is lower than usual (step S1005: Yes), it is determined that there is a pressure abnormality and the process of step S1007 is executed.

[0132] On the other hand, when the control unit 916 determines that the measurement result of the internal standard substance is not abnormal (step S1005 : No), it assumes that a failure other than the liquid delivery pump is suspected (step S1006 ), and ends this flowchart (step S1004 ).

[0133] The control unit 16 checks the value of the pressure sensor 908 included in the double-plunger pump 906 and confirms the section where the pressure is abnormal (step S1007 ).

[0134] If it is confirmed that the pressure drops in sections b and c and increases in sections d and e, it can be determined that the liquid delivery rate of the second plunger pump 910 has decreased, while the liquid delivery rate of the first plunger pump 909 is normal. Therefore, since the control unit 16 confirms the pressure drop in sections b and c, it is suspected that the second check valve 914 is faulty (step S1008).

[0135] Furthermore, if it is confirmed that the pressure increases in intervals b and c and decreases in intervals d and e, it can be determined that the liquid delivery rate of the first plunger pump 909 has decreased, while the liquid delivery rate of the second plunger pump 910 is normal. Therefore, since the control unit 16 has confirmed the pressure decrease in intervals d and e, it is suspected that the first seal 911 or the first check valve 913 is faulty (step S1009).

[0136] If a pressure drop is confirmed throughout the entire interval, it can be determined that the overall liquid delivery volume of the twin-plunger pump 906 has decreased. Therefore, since the control unit 16 confirms a pressure drop throughout the entire interval, it is suspected that the second seal 912 of the twin-plunger pump 906 has failed (step S1010).

[0137] (Variation)

[0138] Furthermore, the present invention is not limited to the above-described embodiments and includes various variations. The above-described embodiments are examples described in detail to facilitate understanding of the present invention and are not necessarily limited to having all the structures described. Furthermore, a portion of the structure of one embodiment may be replaced with a structure of another embodiment, and a structure of another embodiment may be added to a structure of one embodiment. Furthermore, for a portion of the structure of each embodiment, other structures may be added, deleted, or replaced.

[0139] In Example 1, the retention time is used as a characteristic value of the measurement results of the internal standard substance to determine abnormalities in a plurality of dual-plunger pumps (6, 7). In Example 1, the value used for determination can be changed according to the content of the measurement being performed. Specifically, instead of the retention time of the internal standard substance, the half-value width, peak height, peak symmetry, etc. of the internal standard substance can be used to determine abnormalities in the dual-plunger pumps (6, 7). In addition, the specified range for comparison with the characteristic values ​​of the internal standard substance (half-value width, peak height, peak symmetry, etc.) is actually determined according to the purpose of the device user.

[0140] Furthermore, even without the need for measurement, it is possible to use a standard substance solely for the purpose of checking the normal operation of the liquid chromatograph. For example, a known standard substance can be measured in advance for the purpose of instrument inspection to obtain data when the instrument is operating normally. Based on the measurement results, the normal operation of the instrument and the location of the fault in the event of an abnormality can be determined.

[0141] Furthermore, the type and range of pressure anomalies can be defined in the control unit. For example, a periodic (predetermined period) pressure fluctuation exceeding a predetermined pressure fluctuation value (e.g., 5 MPa) can be defined as a pressure anomaly (pressure pulsation anomaly). Alternatively, a pressure anomaly (lowest pressure value anomaly) can be defined as a periodic (predetermined period) pressure fluctuation exceeding a predetermined pressure fluctuation value (e.g., 5 MPa).

[0142] The predetermined change value is a pressure change value that makes analysis of the analyte difficult. The analysis of the analyte includes calculation of retention time, half-value width, peak height, peak area, or peak symmetry in the chromatogram obtained from the detection result of the detection unit.

[0143] The pressure fluctuation value that makes analysis of the substance being measured difficult is the pressure fluctuation value when the retention time, half-value width, peak height, peak area, or peak symmetry of the internal standard substance measured together with the substance being measured exceeds the statistical distribution range when the liquid chromatograph is operating normally. The statistical distribution range when operating normally is the range calculated based on the respective average values ​​and standard deviations of the retention time, half-value width, peak height, peak area, and peak symmetry of the internal standard substance obtained when the liquid chromatograph is operating normally. For example, for the measurement results of the internal standard substance, statistical data of the retention time, half-value width, peak height, and peak symmetry when the device is operating normally can be obtained in advance, and the respective average values ​​and standard deviations can be calculated, thereby also defining the statistical distribution range when operating normally. For example, a deviation from each average value greater than three times the standard deviation can also be defined as a device abnormality.

[0144] Furthermore, the measurement results of the internal standard substance can be defined within a normal range based on statistical data when the device is operating normally, with pressure fluctuations outside this normal range defined as a pressure anomaly. For example, if periodic pressure fluctuations exceed 5 MPa, and if the internal standard substance exceeds the normal range, the definition of a pressure anomaly can be defined as periodic pressure fluctuations exceeding 5 MPa.

[0145] Furthermore, the present invention also encompasses the situation where, once the fault location is determined, the device is immediately stopped and the fault location is notified to the device user. For example, the liquid chromatograph includes a display monitor (display unit 21) for the device user, and the display monitor can display the estimated fault location and notify the device user.

[0146] Description of Reference Numerals

[0147] 1…Sample, 2…Dispensing unit, 3…Separation column, 4…Detection unit, 5…Waste liquid container, 6…First double-plunger pump, 7…Second double-plunger pump, 8a, 8b…Pressure sensor, 9a, 9b…First plunger pump, 10a, 10b…Second plunger pump, 11a, 11b…First seal, 12a, 12b…Second seal, 13a, 13b…First check valve, 14a, 14b…Second check valve, 15a, 15b…Solvent bottle, 16…Control unit, 17…Processor, 18…Main memory Storage unit, 19… auxiliary storage unit, 20… interface, 100… liquid chromatograph, 900… liquid chromatograph, 901… sample, 902… dispensing unit, 903… separation column, 904… detection unit, 905… waste liquid container, 906… double plunger pump, 908… pressure sensor, 909… first plunger pump, 910… second plunger pump, 911… first seal, 912… second seal, 913… first check valve, 914… second check valve, 915… solvent bottle, 916… control unit.

Claims

1. A method for estimating a fault location of a liquid chromatograph, characterized in that: The fault location estimation method comprises the following steps: discharging the solvent into a flow path using a dual plunger pump including a first plunger pump, a second plunger pump disposed downstream of the first plunger pump, and a plurality of consumables involved in discharging the solvent; introducing a sample into the flow path; detecting the pressure of the solvent discharged by the double-plunger pump; Separating the sample into components using a separation column; detecting the components separated by the separation column; as well as A faulty consumable among the plurality of consumables is estimated based on a first pressure detected in a first section where the first plunger pump discharges the solvent into the flow path and a second pressure detected in a second section where the second plunger pump discharges the solvent into the flow path.

2. The fault location estimation method according to claim 1, characterized in that: The fault location estimation method further comprises the following steps: discharging a solvent different from the solvent into the flow path through one or more double-plunger pumps different from the double-plunger pump; When detecting the components of the sample, obtaining the retention time of the internal standard substance supplied to the flow path, and determining whether the retention time is advanced or delayed compared to a predetermined value; as well as A faulty double plunger pump among the plurality of double plunger pumps is estimated based on the determination result of the retention time, the type of the separation column, and the type of the solvent.

3. The fault location estimation method according to claim 1, characterized in that: The plurality of consumables include a first seal of the first plunger pump, a first check valve disposed on the upstream side of the first plunger pump, a second check valve disposed on the downstream side of the first plunger pump, and a second seal of the second plunger pump. The step of inferring the faulty consumables includes: When the first pressure is not abnormal and the second pressure is abnormal, it is inferred that the second check valve is faulty; When the first pressure is abnormal and the second pressure is not abnormal, it is inferred that the first sealing member or the first check valve is faulty; If the first pressure and the second pressure are abnormal, it is estimated that the second seal has failed.

4. The fault location estimation method according to claim 3, characterized in that: The pressure abnormality is a state in which a change in the pressure value during a predetermined period exceeds a predetermined pressure change value, or a state in which an average of the pressure values ​​during a predetermined period becomes equal to or less than a predetermined pressure average value.

5. The fault location estimation method according to claim 4, characterized in that: The predetermined pressure change value is a pressure change value that makes analysis of the substance to be measured difficult.

6. The fault location estimation method according to claim 5, characterized in that: The analysis of the substance to be measured includes calculation of retention time, half-value width, peak height, peak area or peak symmetry in the chromatogram obtained from the detection results of each component.

7. The fault location estimation method according to claim 5, characterized in that: The pressure fluctuation value that makes analysis of the analyte difficult is a pressure fluctuation value where the retention time, half-value width, peak height, peak area or peak symmetry of the internal standard substance measured together with the analyte exceeds the statistical distribution range of the liquid chromatograph under normal conditions.

8. The fault location estimation method according to claim 7, characterized in that: The statistical distribution range of the liquid chromatograph under normal operation is the range calculated based on the respective mean values ​​and standard deviations of the retention time, half-value width, peak height, peak area and peak symmetry of the internal standard substance obtained when the liquid chromatograph operates normally.

9. A liquid chromatograph, characterized in that The liquid chromatograph has: A double plunger pump comprising a first plunger pump, a second plunger pump disposed downstream of the first plunger pump, and a plurality of consumables involved in discharging a solvent; a pressure sensor for detecting the pressure of the solvent discharged by the double-plunger pump; a dispensing portion for introducing a sample into a flow channel; a separation column connected to the downstream side of the dispensing portion and separating the sample into components; a detection unit for detecting each component separated by the separation column; as well as The control unit estimates a faulty consumable among the plurality of consumables based on a first pressure detected by the pressure sensor in a first section in which the first plunger pump discharges the solvent into the flow path and a second pressure detected by the pressure sensor in a second section in which the second plunger pump discharges the solvent into the flow path.

10. The liquid chromatograph according to claim 9, characterized in that The liquid chromatograph further comprises: one or more double plunger pumps, which are different from the double plunger pumps and discharge a solvent different from the solvent into the flow path; When detecting the components of the sample, the control unit obtains the retention time of the internal standard substance supplied to the flow path, determines whether the retention time is advanced or delayed compared to a specified value, and infers a faulty double-plunger pump among the multiple double-plunger pumps based on the determination result of the retention time, the type of the separation column, and the type of the solvent.

11. The liquid chromatograph according to claim 9, characterized in that The liquid chromatograph includes a storage unit storing a reference table including information on a section where a pressure abnormality has occurred and information on a failed consumable. The control unit estimates a faulty consumable among the plurality of consumables based on the first pressure, the second pressure, and the reference table.

12. The liquid chromatograph according to claim 9, characterized in that The liquid chromatograph has: The plurality of consumables include a first seal of the first plunger pump, a first check valve disposed on the upstream side of the first plunger pump, a second check valve disposed on the downstream side of the first plunger pump, and a second seal of the second plunger pump. The control unit includes the following processing: When the first pressure is not abnormal and the second pressure is abnormal, it is inferred that the second check valve is faulty; When the first pressure is abnormal and the second pressure is not abnormal, it is inferred that the first sealing member or the first check valve is faulty; If the first pressure and the second pressure are abnormal, it is estimated that the second seal has failed.

13. The liquid chromatograph according to claim 12, characterized in that The pressure abnormality is a state in which a change in the pressure value during a predetermined period exceeds a predetermined pressure change value, or a state in which an average of the pressure values ​​during a predetermined period becomes equal to or less than a predetermined pressure average value.

14. The liquid chromatograph according to claim 9, characterized in that The liquid chromatograph further includes a display unit that displays information on the consumables estimated to be faulty.

15. A method for estimating a fault location of a liquid chromatograph, characterized in that: The fault location estimation method comprises the following steps: Multiple solvents are mixed and discharged into the flow path through multiple plunger pumps; introducing a sample into the flow path; Separating the sample into components using a separation column; detecting the components separated by the separation column; When detecting the components of the sample, obtaining the retention time of the internal standard substance supplied to the flow path, and determining whether the retention time is advanced or delayed compared to a predetermined value; as well as Based on the determination result of the holding time, a failed plunger pump among the plurality of plunger pumps is estimated.

16. The fault location estimation method according to claim 15, characterized in that: The plunger pump estimated to have failed includes estimating a plunger pump estimated to have failed among a plurality of plunger pumps based on the determination result of the retention time, the type of the separation column, and the type of the solvent.

17. A liquid chromatograph, characterized in that: have: a plurality of plunger pumps for mixing the plurality of solvents and discharging them into the flow path; a dispensing portion for introducing a sample into the flow path; a separation column connected to the downstream side of the dispensing portion and separating the sample into components; a detection unit that detects each component separated by the separation column; and The control unit obtains a retention time of an internal standard substance supplied to the flow path when detecting components of the sample, determines whether the retention time is advanced or delayed compared to a specified value, and estimates a faulty plunger pump among the plurality of plunger pumps based on the retention time determination result.

18. The liquid chromatograph according to claim 17, characterized in that The control unit estimates a faulty plunger pump among the plurality of plunger pumps based on the determination result of the retention time, the type of the separation column, and the type of the solvent.

19. The liquid chromatograph according to claim 17, characterized in that The liquid chromatograph includes a storage unit storing a reference table including information on whether the retention time of an internal standard substance is earlier or later than a predetermined time range and information on a failed plunger pump. The control unit estimates a failed plunger pump among the plurality of plunger pumps based on the determination result of the holding time and the reference table.

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