Electrolyte analysis device and analysis method

Abstract

Provided is an electrolyte analysis apparatus which is intended to measure the concentration of ions in a liquid and is equipped with an electrolyte analysis unit including an ion-selective electrode to be used for the measurement of a specific ion and a reference electrode, a diluent supply unit for supplying a diluent for diluting a reagent or a specimen, and a control device, in which the control device measures each of diluted reagents which are produced by diluting a reagent having a known concentration with the diluent and have a plurality of different concentrations and in each of which the concentration of a specific ion is known, and then the control device performs a water quality determination processing with respect to the diluted solutions on the basis of slopes obtained from results of the measurement. It becomes possible to reduce the burden on the measurement while preventing the deterioration in accuracy of results of the measurement.

Description

[Technical field]

[0001] The present invention relates to an electrolyte analyzer and an analysis method. [Background technology]

[0002] An electrolyte analyzer is a device that measures the concentration of a specific electrolyte contained in an electrolyte solution (hereinafter sometimes referred to as a specimen) such as human blood or urine. For example, there is a device that uses an ion selective electrode method that uses an ion selective electrode (ISE) to measure the concentration. As an electrolyte analyzer, for example, a flow-type electrolyte analyzer is known. In a flow-type electrolyte analyzer, serum as an electrolyte solution is supplied directly or a sample solution diluted with a specimen dilution solution to an ion selective electrode, and the liquid junction potential between the ion selective electrode and the reference electrode solution is measured. Subsequently (or prior to the measurement), a standard solution with a known electrolyte concentration is supplied to the ion selective electrode, and the liquid junction potential with the reference electrode solution is measured in the same manner as with the serum (or sample solution). Then, the electrolyte concentration of the serum (or sample solution) can be calculated from the two liquid junction potentials, the liquid junction potential of the standard solution and the liquid junction potential of the serum (or sample solution).

[0003] As an example of a measurement method using such an electrolyte analyzer, Patent Document 1 discloses a method for measuring chloride ion concentration in which a chloride ion selective electrode and a reference electrode are immersed in a liquid to be measured, and the chloride ion concentration in the liquid to be measured is measured based on the potential difference between the two electrodes. The chloride ion selective electrode is a silver / silver chloride electrode, and the solution in contact with the electrode contains silver chloride dissolved at a saturation concentration.

[0004] Furthermore, Patent Document 2 discloses an electrolyte concentration measuring device including an active ingredient supplying unit that supplies an active ingredient corresponding to a reagent contained in a bottle, a pure water supplying unit that supplies pure water to the bottle, and a stirring mechanism that stirs and mixes the active ingredient and the pure water inside the bottle to which the active ingredient is supplied from the active ingredient supplying unit and the pure water is supplied from the pure water supplying unit. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 8-211016 [Patent Document 2] JP 2018-17543 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the conventional technology described in Patent Document 1, a silver nitrate solution (AgNO3) is used as a diluent. However, when a silver nitrate solution is used as a diluent, wastewater treatment is indispensable in consideration of the environmental load, and this wastewater treatment leads to an increase in treatment costs and treatment time. In particular, in large-scale hospitals and clinical testing centers that perform many measurement processes, the amount of diluent used and the amount of wastewater discharged are large, resulting in a huge burden in terms of running costs and the like.

[0007] In addition, in the conventional technology described in Patent Document 2, the diluted solution is produced by mixing the original solution of the diluted solution with pure water. However, even in this case, wastewater treatment is essential in consideration of the environmental load. In addition, pure water is used to dilute the original solution, but pure water is not standardized in the clinical testing field, so there is a possibility that unspecified ions contained in the pure water may cause errors in the measurement results of the electrolyte analyzer.

[0008] The present invention has been made in consideration of the above, and aims to provide an electrolyte analyzer and an analysis method that can reduce the burden associated with the measurement while suppressing a decrease in the accuracy of the measurement results. [Means for solving the problem]

[0009] The present application includes multiple means for solving the above problems. One example is an electrolyte analyzer that measures the concentration of ions in a liquid, the electrolyte analyzer having an electrolyte analysis unit including an ion selective electrode used to measure a specific ion and a comparison electrode, a diluent supply unit that supplies a diluent for diluting a reagent or sample, and a control device. The control device measures diluted reagents of different concentrations, each having a known concentration of the specific ion, produced by diluting a reagent of known concentration with the diluent, and performs a water quality determination process for the diluted liquid based on the slope obtained from the measurement results. Effect of the Invention

[0010] It is possible to reduce the burden associated with the measurement while suppressing a decrease in the accuracy of the measurement results. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating an overall configuration of an electrolyte analyzer according to a first embodiment. [Diagram 2] This figure shows the relationship between the potential difference between an ion selective electrode and a comparison electrode and the concentration of the ion to be measured when system water in which the ion to be measured by the ion selective electrode is dissolved is measured using an electrolyte analyzer. [Diagram 3] 4 is a flowchart showing a water quality determination process according to the first embodiment. [Figure 4] 10 is a flowchart showing a water quality determination process according to a second embodiment. [Diagram 5] 13 is a flowchart showing a water quality determination process according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0013] <First embodiment> A first embodiment of the present invention will be described in detail with reference to FIGS.

[0014] 1 is a diagram showing a schematic overall configuration of an electrolyte analyzer according to an embodiment of the present invention. In this embodiment, a flow-type electrolyte analyzer using an ion selective electrode (ISE) (hereinafter simply referred to as an electrolyte analyzer) will be shown and described as an example of the electrolyte analyzer.

[0015] In FIG. 1, the electrolyte analyzer 100 is generally composed of a sample dispensing device 101, an ion selective electrode group 102, a reference electrode 103, an internal standard solution bottle 104, a reference electrode solution bottle 105, a dilution tank 106, a water supply tank 107, syringes 108a-108d, valves 109a-109k, a waste liquid tank 110, and a control device 111.

[0016] The specimen dispensing device 101 includes a sample probe 101a and a sample container 101b. The sample probe 101a performs a dispensing process of aspirating a sample (such as a patient's specimen) held in the sample container 101b and discharging it into a dilution tank 106. Here, the specimen is a general term for an analysis target collected from a patient's living body, such as blood or urine. The specimen may also be one that has been pretreated with respect to these analysis targets.

[0017] High-purity water (hereinafter referred to as system water) that is generally used in electrolyte analyzers is stored in the water supply tank 107. The system water is supplied to the water supply tank 107 via a valve 109a from a pure water production device (not shown). The system water stored in the water supply tank 107 is discharged into the dilution tank 106 via a system water nozzle 107a by the operation of a syringe (system water syringe) 108a and valves 109b and 109c.

[0018] The internal standard bottle 104 contains a standard solution having a known ion concentration determined in advance for the ion species to be measured by the electrolyte analyzer 100. The internal standard solution contained in the internal standard bottle 104 is prepared so as to contain, for example, sodium ions (Na+), potassium ions (K+), chlorine ions (Cl-), etc. The internal standard solution contained in the internal standard bottle 104 is discharged into the dilution tank 106 through the internal standard solution nozzle 104a by the operation of the syringe (internal standard solution syringe) 108b and the valves 109d and 109e.

[0019] A temperature regulator 116 is provided in the flow paths of the system water nozzle 107a and the internal standard solution nozzle 104a, and the temperatures of the system water and the internal standard solution passing through the flow paths are adjusted to be within a predetermined temperature range.

[0020] The reference electrode solution bottle 105 contains a reference electrode solution with a predetermined known ion concentration. The reference electrode solution contained in the reference electrode solution bottle 105 is, for example, an aqueous solution of potassium chloride (KCl) containing potassium ions (K+) and chloride ions (Cl-). The reference electrode solution contained in the reference electrode solution bottle 105 is sent to the reference electrode 103 by the operation of the syringe (reference electrode solution syringe) 108c and the valves 109f and 109g.

[0021] The sample dispensed into the dilution tank 106 is diluted and stirred with system water discharged from the water supply tank 107 through the system water nozzle 107a by the operation of the syringe (system water syringe) 108a and the valves 109b and 109c into the dilution tank 106. Note that, in the present embodiment, the case where system water is used as a diluting liquid for diluting the sample is exemplified, but the sample may be diluted using other diluting liquids. The sample diluted with system water in the dilution tank 106 is sent to the ion selective electrode group 102 through the shipper nozzle 102a by the operation of the syringe (shipper syringe) 108d and the valves 109h and 109i. Note that, at this time, the pinch valve 112 provided in the flow path between the ion selective electrode group 102 and the reference electrode 103 is temporarily opened.

[0022] Similarly to the diluted sample, the internal standard solution discharged into the dilution tank 106 is sent to the ion selective electrode group 102 through the shipper nozzle 102a by the operation of the syringe (shipper syringe) 108d and the valves 109h and 109i.

[0023] An ion-sensitive membrane having a property that the electromotive force changes according to the concentration of a specific ion (e.g., sodium ion (Na+), potassium ion (K+), chloride ion (Cl-), etc.) in the sample solution is attached to the multiple ion-selective electrodes constituting the ion-selective electrode group 102. This allows the ion-selective electrode group 102 to output an electromotive force according to the concentration of each ion in the sample solution.

[0024] When the pinch valve 112 is opened while the diluted sample is being sent to the ion selective electrode group 102 and the reference electrode solution is being sent to the reference electrode 103, the diluted sample and the reference electrode solution sent to the flow path come into contact with each other, and electrical conductivity is established between the ion selective electrode group 102 and the reference electrode 103 in the flow path.

[0025] The potential difference between each ion selective electrode of the ion selective electrode group 102 and the reference electrode 103 is measured by a voltmeter 113, and the measurement result (electrical signal) is sent to the control device 111 via an amplifier 114. In addition, before or after the measurement of the diluted sample, the internal standard solution is measured in the same manner as the measurement of the diluted sample.

[0026] Although not shown, the control device 111 controls the overall operation of the electrolyte analyzer 100 and can be configured by a computer equipped with a calculation device such as a CPU (Central Processing Unit), a storage device such as a RAM (Random Access Memory) or a HHD (Hard Disk Drive), and an input / output device such as an I / O port. The storage device and the input / output device are configured to be able to exchange data with the calculation device via an internal bus or the like. The input / output device is connected to each mechanism of the electrolyte analyzer 100, and the control device 111 controls the operation of each mechanism via the input / output device.

[0027] The control device 111 calculates the concentration of a specific electrolyte contained in the sample based on the potential difference between each ion selective electrode of the ion selective electrode group 102 and the reference electrode 103. In addition, by performing calibration based on the measurement result of the internal standard solution, the electrolyte concentration of the sample can be measured more accurately. Note that a person skilled in the art can appropriately design a specific method of calibration based on known techniques, etc. The control device 111 stores the ion concentration calculated for each ion in a storage unit (not shown) and outputs it to an output device (e.g., a display device).

[0028] The sample and internal standard solution remaining in the dilution tank 106 are sucked by the waste liquid nozzle 115a through the operation of the vacuum bottle 115 and the valves 109j and 109k, and sent to the waste liquid tank 110.

[0029] In the electrolyte analysis device 100 of this embodiment configured as described above, the ion concentration of the system water in the water supply tank 107 is measured by the water quality measurement unit 200 (ion selective electrode group 102, reference electrode 103, and voltmeter 113), and the control device 111 performs a water quality determination process based on the measurement results to determine whether the quality of the system water is normal or abnormal.

[0030] First, the principle of the water quality determination process of this embodiment will be described.

[0031] FIG. 2 shows the relationship between the potential difference between an ion-selective electrode and a comparison electrode and the concentration of the ion to be measured when system water (hereinafter, ionic solution) in which the ion to be measured by the ion-selective electrode has been dissolved is measured using an electrolyte analyzer.

[0032] As shown in FIG. 2, for example, when the ionic solution does not contain ions (hereinafter referred to as interfering ions) that inhibit the ion selectivity of the ion-selective electrode group 102, the concentration logarithm (mmol / l) and the potential difference (mV) show a proportional relationship regardless of whether the concentration of the ion to be measured is high or low. On the other hand, when the ionic solution contains a certain amount or more of interfering ions, when the concentration of the ion to be measured is low, the relationship between the concentration logarithm (mmol / l) and the potential difference (mV) deviates from the proportional relationship, and the slope of the relationship between the concentration logarithm (mmol / l) and the potential difference (mV) changes. This change in slope becomes more noticeable as the concentration of the interfering ions increases. Note that when the concentration of the ion to be measured is high, the slope of the relationship between the concentration logarithm (mmol / l) and the potential difference (mV) hardly changes regardless of the presence or absence of interfering ions (provided that the concentration of the ion is sufficiently low compared to the concentration of the ion to be measured).

[0033] Thus, by using system water, a plurality of types of ion solutions with known concentrations of the ions to be measured are generated for each of the high concentration range and the low concentration range, and the potential difference between the ion selective electrode group 102 and the reference electrode 103 is measured to obtain the slope of the relationship between the logarithm value (mmol / l) and the potential difference (mV), thereby estimating the concentration of the interfering ions contained in the system water. In addition, by changing the concentration of the interfering ions in the system water and experimentally obtaining the slope of the relationship between the logarithm value (mmol / l) and the potential difference (mV), it is possible to obtain the slope at the boundary between the concentration of the interfering ions that is tolerable and the concentration that is not tolerable in terms of the effect on the measurement accuracy of the electrolyte analyzer 100, and by using this slope as a threshold value, a water quality determination process can be performed to determine whether the quality of the system water is good (normal) or abnormal.

[0034] In this embodiment, an example is described in which chlorine ions (Cl-) are measured using a diluted internal standard solution prepared by diluting an internal standard solution with system water as an ionic solution. A water quality determination process is performed based on the results of measuring multiple types (e.g., two types) of diluted internal standard solutions with different known concentrations in the high concentration range and the low concentration range.

[0035] In this embodiment, the measurement of chloride ions (Cl-) using an internal standard solution is described in detail, but any ion solution of known concentration containing a specific ion to be measured by the ion selective electrode can perform the water quality determination process in the same manner, and is not limited to the type of ion or the type of reagent. The electrolyte analyzer 100 in FIG. 1 can perform the water quality determination process using sodium ions (Na+) or potassium ions (K+). In addition, when an ion selective electrode for measuring magnesium ions (Mg++) or an ion selective electrode for measuring lithium ions (Li+) is provided, the water quality determination process can also be performed using magnesium ions (Mg++) or lithium ions (Li+). In this embodiment, the measurement of the diluted internal standard solution is described in detail, but a reference electrode solution or a calibrator used for calibration can be used instead of the internal standard solution. Reagents with different known concentrations may be used, such as using an internal standard solution and a calibrator in the low concentration range and the high concentration range, respectively.

[0036] Specifically, the internal standard solution in the internal standard solution bottle 104 is discharged into the dilution tank 106 through the internal standard solution nozzle 104a, and the system water in the water supply tank 107 is discharged into the dilution tank 106 through the system water nozzle 107a. The internal standard solution of known concentration is diluted by the system water at a predetermined ratio to generate the diluted internal standard solution. The diluted internal standard solution has two types of concentrations, for example, chlorine ion (Cl-) concentrations in the high concentration range of 80 (mmol / l) and 120 (mmol / l). For the diluted internal standard solutions of these two types of concentrations, the potential difference between the ion selective electrode group 102 and the reference electrode 103 is measured by the voltmeter 113, and the measurement results are plotted with the electrolyte concentration (logarithm) on the horizontal axis and the potential difference on the vertical axis. Then, a linear regression line is drawn between two points of the measurement results, and the slope is obtained. This slope is set as the slope at high concentration (SL1).

[0037] The concentrations of the diluted internal standard solution in the low concentration range are, for example, two types of chloride ion (Cl-) concentrations of 8 (mmol / l) and 12 (mmol / l). As in the high concentration range, the potential difference between the ion selective electrode group 102 and the reference electrode 103 for the diluted internal standard solutions of these two concentrations is measured by the voltmeter 113, and the measurement results are plotted with the electrolyte concentration (logarithm) on the horizontal axis and the potential difference on the vertical axis. Then, a linear regression line is drawn between the two points of the measurement results, and the slope is determined. This slope is defined as the slope at the low concentration (SL2).

[0038] For example, when the lower measurement limit of each ion selective electrode of the ion selective electrode group 102 is sufficiently lower than 0.2 (mmol / l), if the system water does not contain interfering ions, the slope SL1 obtained using the diluted internal standard solution in the high concentration range and the slope SL2 obtained using the diluted internal standard solution in the low concentration range will show the same value. Therefore, the ratio of the slope SL2 based on the slope SL1 is (SL2 / SL1×100)=100(%). On the other hand, if the system water contains interfering ions, the measurement sensitivity in the low concentration range decreases due to the influence of the interfering ions, and the ratio of the slope SL2 based on the slope SL1 (SL2 / SL1×100) will be lower than 100(%). For example, if the threshold concentration of interfering ions is set to 1.0 (mmol / l) taking into account the impact of interfering ions on measurement accuracy, when the ratio of slope SL2 to slope SL1 (SL2 / SL1 x 100) is 92% or less, it can be determined that the impact on measurement accuracy is unacceptable, i.e., the water quality of the system water is abnormal.

[0039] Although the detailed explanation was given using a specific chloride ion (Cl-) concentration as an example, the concentration is not limited to the above, and it is sufficient if the slope can be obtained for both the high and low concentration ranges. After investigation, it was found that the concentration range of the high concentration range is preferably about 10 times or more that of the low concentration range. The larger the concentration difference between the high and low concentration ranges, the more noticeable the difference in slope will be, and the more accurately water quality abnormalities can be determined.

[0040] In addition, the appropriate concentration range varies depending on the type of ion, and when performing the water quality determination process with chloride ions (Cl-), the high concentration range is 80-120 (mmol / l) and the low concentration range is 8-12 (mmol / l), when performing the water quality determination process with potassium ions (K+), the high concentration range is 3-7 (mmol / l) and the low concentration range is 0.3-0.7 (mmol / l), and when performing the water quality determination process with sodium ions (Na+), the high concentration range is 120-160 (mmol / l) and the low concentration range is 12-16 (mmol / l). Note that the accuracy of the water quality determination process can be improved by performing the water quality determination process within the above-mentioned concentration ranges, but the water quality determination process is also possible outside the above-mentioned concentration ranges.

[0041] The above-mentioned slopes SL1 and SL2 can be calculated by the following (Equation 1). SL=(EMFH-EMFL) / (LogCH-LogCL)…(Formula 1)

[0042] In formula 1, EMFH is the measured electromotive force of the high-concentration diluted internal standard solution, EMFL is the measured electromotive force of the low-concentration diluted internal standard solution, CH is the specified concentration value of the high-concentration diluted internal standard solution, and CL is the specified concentration value of the low-concentration diluted internal standard solution. Note that the specified concentration value of the high-concentration diluted internal standard solution and the specified concentration value of the low-concentration diluted internal standard solution are the specified concentration values ​​of high and low concentrations in each concentration range.

[0043] The concentration of the internal standard solution can be calculated using the following (Equation 2) and (Equation 3). CIS=CL×10a…(Formula 2) a = (EMFIS-EMFL) / SL…(Equation 3)

[0044] where CIS is the concentration of the internal standard solution and EMFIS is the electromotive force of the internal standard solution.

[0045] The concentration of the sample is calculated using the following formula (4). E=E0+(2.303RT / zF)·logCS…(Equation 4)

[0046] where CS is the sample concentration, E is the potential difference (mV) between the ion-selective electrode and the reference electrode, E0 is the reference potential (mV), R is the gas constant (8.3144 J mol-1 K-1), T is the absolute temperature (273.15+°C), n is the ionic valence, and F is the Faraday constant (96.485 C mol).

[0047] FIG. 3 is a flowchart showing the water quality determination process.

[0048] In FIG. 3, when an instruction to start analysis is given, the control device 111 first performs a reset operation (step S100).

[0049] Next, diluted internal standard solutions of multiple concentrations are generated and measured by the water quality measurement unit 200 (ion selective electrode group 102, reference electrode 103, voltmeter 113), and the electromotive force (potential difference) of each is measured (step S110).

[0050] Next, the slopes SL1 and SL2 are calculated from the measurement results of the high-concentration diluted internal standard solution and the low-concentration diluted internal standard solution (step S120), and it is determined whether the slope SL2 is within a reference range (step S130). Here, whether the slope SL2 is within a reference range means, for example, whether the ratio of the slope SL2 to the slope SL1 (SL2 / SL1×100) is 92(%) or more, as described above.

[0051] If the result of the determination in step S130 is YES, the system water quality is determined to be normal (good), the sample concentration is measured (step S140), the measurement result is output (step S150), and the process ends. At this time, since the quality of the system water is guaranteed, the measurement result can be obtained with high accuracy.

[0052] If the determination result in step S130 is NO, the system water quality is determined to be abnormal, a water quality abnormality alarm is issued (step S131), the operation of the device is stopped (step S132), and the process is terminated. At this time, since the system water quality is detected to be abnormal and sample measurement is not performed, it is possible to prevent low-accuracy (low-reliability) measurement, and by notifying the operator of the abnormality, it is possible to encourage quick improvement and recovery from the abnormal state.

[0053] In the flowchart of FIG. 3, the details are explained by taking as an example the case where the water quality determination process is performed at the start of the analysis, but it is also possible to perform only the water quality determination process at any timing.

[0054] The effects of the present embodiment configured as above will be described.

[0055] In conventional technology using silver nitrate solution (AgNO3) as diluent, wastewater treatment is indispensable in consideration of environmental load, and this wastewater treatment leads to an increase in treatment cost and treatment time. In particular, in large-scale hospitals and clinical testing centers that perform many measurement processes, the amount of diluent used and the amount of wastewater discharged are large, resulting in a huge burden in running costs and other costs. In conventional technology that produces diluent by mixing the original diluent solution with pure water, the pure water is not standardized, so there is a possibility that unspecified ions contained in the pure water will cause errors in the measurement results of the electrolyte analyzer.

[0056] In contrast, in the present embodiment, in an electrolyte analyzer that measures the concentration of ions in a liquid, the electrolyte analyzer has an ion selective electrode used to measure specific ions and an electrolyte analysis unit including a reference electrode, a diluent supply unit that supplies a diluent for diluting a reagent or sample, and a control device, the control device is configured to measure diluted reagents of different concentrations, each having a known concentration of a specific ion, produced by diluting a reagent of known concentration with diluent, and to perform a water quality determination process for the diluent based on the slope obtained from the measurement results, thereby suppressing a decrease in the accuracy of the measurement results while reducing the burden associated with the measurement.

[0057] <Second embodiment> A second embodiment of the present invention will now be described with reference to FIG.

[0058] In this embodiment, an example will be described in which, instead of issuing an alarm when the interfering ion concentration is not within the reference range, a correction coefficient is calculated. The other configurations are the same as those of the first embodiment, and only the differences from the first embodiment will be described.

[0059] 4 is a flowchart showing the water quality determination process according to this embodiment. The process when the slope is within the standard range (i.e., the process of steps S100 to S150) is the same as in the first embodiment, so only the process of steps S231 to S232 will be described in this embodiment.

[0060] 4, if the result of the determination in step S130 is NO, the system water quality is determined to be abnormal, a correction coefficient is calculated (step S231), and a sample concentration measurement operation is performed (step S232). The sample measurement result is corrected by applying the correction coefficient to the sample measurement result (step S233), and the process ends.

[0061] Here, the correction coefficient corrects for variations in the sample measurement results due to the influence of interfering ions, and for example, the amount of variation in the sample measurement results relative to the interfering ion concentration is experimentally determined in advance, and a correction coefficient according to the measured interfering ion concentration is applied to the sample measurement results to obtain more accurate measurement results. In other words, even if an abnormality is detected in the water quality of the system water, the sample measurement results are corrected according to the interfering ion concentration, so that highly accurate measurement can be performed without stopping the sample measurement operation.

[0062] The present embodiment configured as above can also provide the same effects as the first embodiment. Furthermore, even if an abnormality in the water quality is detected, it becomes possible to continue the measurement. <Third embodiment> A third embodiment of the present invention will now be described with reference to FIG.

[0063] In this embodiment, a water quality determination process after the water supply tank 107 is cleaned will be described.

[0064] To keep the system water in a normal condition, the user periodically adds detergent to the water supply tank 107 and cleans it. Detergents are, for example, sodium hypochlorite containing chlorine ions (Cl-) and sodium ions (Na+), or chlorine dioxide containing chlorine ions (Cl-). If rinsing after cleaning is insufficient, the ions in the detergent may act as interfering ions and affect the measurement results of the sample. Therefore, in this embodiment, an example of performing a water quality determination process after cleaning the water supply tank 107 will be described.

[0065] FIG. 5 is a flow chart showing the cleaning process according to this embodiment.

[0066] 5, when a cleaning command is issued, first, detergent is put into the water supply tank 107 to clean the water supply tank (step S300), and the system water in the water supply tank 107 containing the detergent is replaced to rinse the water supply tank (step S310). Next, in order to check whether detergent remains in the water supply tank after the rinsing operation, the electromotive forces of ion solutions of multiple concentrations are measured (step S320), and a slope is generated from the measurement result (step S330). Next, it is determined whether the slope SL2 is within a reference range (step S340). The processing of steps S320 to S330 is similar to steps S110 to S130 in the first embodiment, and therefore detailed description will be omitted.

[0067] If the determination result in step S340 is YES, it is determined that no detergent remains (rinsing is sufficient) and the process ends. If the determination result in step S340 is NO, it is determined that rinsing is insufficient and detergent remains, and the process returns to step S310, and the rinsing operation is repeated by repeating the processes of steps S310 to S330 until the determination result becomes YES.

[0068] In this embodiment, since the rinsing sufficientness is detected by detecting the concentration of ions contained in the detergent, the ionic solution must contain at least the ions that are contained in the detergent and that are the target ions for measurement by the ion selective electrode.

[0069] In this embodiment, it is possible to confirm that no detergent remains after the cleaning process of the water supply tank 107, and therefore it is possible to prevent the detergent from affecting the measurement results of the sample.

[0070] In addition, although the above example shows the washing and rinsing operations being performed automatically, the washing and rinsing operations may also be performed manually by the user. In the case where the washing and rinsing operations are performed manually by the user, the user instructs the execution of the water quality determination process to perform steps S320 to S330, and notifies the user whether detergent remains, and if it is determined in step S340 that the slope SL2 is outside the reference range and detergent remains, the user can be prompted to perform additional rinsing.

[0071] <Other embodiments> The present invention is not limited to the above-described embodiment, and includes various modifications and combinations within the scope of the invention.

[0072] For example, in the first to third embodiments, SL1 and SL2 were obtained by measuring the ion solution in the high concentration range and the ion solution in the low concentration range, but the ion solution in the high concentration range was not measured. A theoretical value may be obtained instead of SL1. Since the theoretical value and the actual measurement value are different, the accuracy of the water quality determination is lower than when the ion solution is measured and SL1 is obtained, but the slope when no interfering ions are included can be calculated using the theoretical value, and it becomes possible to save the reagents used in the water quality determination process. In addition, in the above-mentioned embodiment, a high-concentration ion solution and a low-concentration ion solution are measured in the high concentration range and the low concentration ion solution, respectively, but SL1 and SL2 may be obtained using ion solutions of the same concentration in the low concentration ion solution in the high concentration range and the high concentration ion solution in the low concentration range. As described above, the water quality can be determined with high accuracy if there is a difference in concentration range of about 10 times between the high concentration range and the low concentration range, but if the slope between the low concentration range and the high concentration range can be reduced, the water quality can be determined, and it becomes possible to save the reagents used in the water quality determination process.

[0073] <Additional Notes> The present invention is not limited to the above-described embodiments, and includes various modifications and combinations within the scope of the gist of the present invention. The present invention is also not limited to those having all the configurations described in the above-described embodiments, and includes those in which some of the configurations are deleted. The above-described configurations, functions, etc. may be realized in part or in whole by designing, for example, an integrated circuit. The above-described configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function. [Explanation of symbols]

[0074] 100, 100A, 100B... electrolyte analyzer, 101... sample dispenser, 101a... sample probe, 101b... sample container, 102... ion selective electrode group, 102a... sipper nozzle, 103... reference electrode, 104... internal standard solution bottle, 104a... internal standard solution nozzle, 105... reference electrode solution bottle, 106... dilution tank, 107... water supply tank, 107a... system water nozzle, 108a...system water syringe, 108b...internal standard solution syringe, 108c...reference electrode solution syringe, 108d...sipper syringe, 109a to 109k...valves, 110...waste tank, 111...control device, 112...pinch valve, 113...voltmeter, 114...amplifier, 115...vacuum bottle, 115a...waste nozzle, 116...temperature regulator, 200...water quality measurement unit

Claims

1. an electrolyte analysis unit including an ion selective electrode used to measure a specific ion and a reference electrode; a diluent supply unit for supplying a diluent for diluting a reagent or a sample; A control device; An electrolyte analyzer for measuring an ion concentration in a liquid, comprising: The control device measures a plurality of different concentrations of diluted reagents each having a known concentration of the specific ion, the diluted reagents being produced by diluting a reagent having a known concentration with the diluting liquid; When performing the water quality determination process of the diluted solution based on the slope obtained from the measurement result, An electrolyte analyzer characterized by measuring four different concentrations of the diluted reagent and performing a water quality determination process of the diluted liquid based on the slope obtained from the measurement results of two concentrations in the high concentration range and the slope obtained from the measurement results of two concentrations in the low concentration range.

2. 2. The electrolyte analyzer according to claim 1, Electrolyte analyzer according to claim 1, wherein the reagent of known concentration is an internal standard solution, a calibrator or a reference electrode solution.

3. 2. The electrolyte analyzer according to claim 1, 13. An electrolyte analyzer according to claim 12, wherein the concentration of the high concentration region is 10 times or more higher than the concentration of the low concentration region.

4. 4. The electrolyte analyzer according to claim 3, The specific ion In the case of chloride ion (Cl-), the concentration range of the low concentration region is 8-12 (mmol / l), In the case of potassium ion (K+), the low concentration range is 0.3-0.7 (mmol / l), In the case of sodium ion (Na+), the low concentration range is 12-16 (mmol / l). The electrolyte analyzer according to claim 1,

5. 3. The electrolyte analyzer according to claim 1, The specific ion Chloride ion (Cl-) 8-12 (mmol / l), In the case of potassium ion (K+), 0.3-0.7 (mmol / l), Sodium ion (Na+) 12-16 (mmol / l), The electrolyte analyzer according to claim 1, further comprising: a dilution reagent having an ion concentration selected from the range of 1 to 100; and a water quality determination process for the dilution reagent based on a slope obtained from the results of measuring the dilution reagent at multiple concentrations.

6. The electrolyte analyzer according to any one of claims 1 to 5, The control device is an electrolyte analyzer characterized in that when the water quality of the diluting solution is determined to be abnormal in the water quality determination process, the control device corrects the measurement results of the sample using the ion selective electrode using a correction coefficient predetermined according to the ion concentration of the diluting solution.

7. The electrolyte analyzer according to any one of claims 1 to 5, The electrolyte analyzer according to claim 1, further comprising: a detecting unit for detecting a water quality of the diluted solution;

8. The electrolyte analyzer according to any one of claims 1 to 5, A water supply tank for storing the dilution liquid, This electrolyte analyzer is characterized in that if the water quality of the diluted solution is determined to be abnormal during the water quality determination process after a cleaning process including cleaning and rinsing the water supply tank using a detergent, it is determined that detergent remains.

9. The electrolyte analyzer according to any one of claims 1 to 7, The electrolyte analyzer according to claim 1, wherein the diluent is system water.

10. An analytical method for measuring the ion concentration of a specific ion in a liquid based on the potential difference between an ion-selective electrode and a reference electrode, comprising: When performing a water quality determination process of the dilution liquid based on a slope obtained from a measurement result of each of a plurality of dilution reagents having known concentrations of the specific ion, the dilution reagents being produced by diluting a reagent of known concentration with a dilution liquid for diluting a reagent or a specimen, An analytical method characterized by performing a water quality determination process for the diluted solution based on the slope obtained from the measurement results of two concentrations in the high concentration range and the slope obtained from the measurement results of two concentrations in the low concentration range, among the measurement results obtained by measuring the diluted reagent at four different concentrations.

11. The method of claim 10, The specific ion Chloride ion (Cl-) 8-12 (mmol / l), In the case of potassium ion (K+), 0.3-0.7 (mmol / l), Sodium ion (Na+) 12-16 (mmol / l), The method comprises the steps of: determining the water quality of the diluted solution based on a slope obtained from measurements of a diluted reagent having an ion concentration selected from the range above at multiple concentrations.

12. The method according to claim 10 or 11, An analytical method characterized in that, when the water quality of the dilution wall is judged to be abnormal by the water quality judgment process, the measurement result of the sample by the ion selective electrode is corrected using a correction coefficient predetermined according to the ion concentration of the dilution liquid.

13. The method according to claim 10 or 11, A cleaning process including a cleaning process using a detergent in a water supply tank that stores a dilution liquid and a rinsing process, The analytical method is characterized in that, if the water quality of the diluted solution is determined to be abnormal in the water quality determination process after the cleaning process, it is determined that detergent remains.

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