Electrolyte Analysis Device

Abstract

To provide an electrolyte analyzer capable of easily determining the type or concentration of interfering ions.SOLUTION: The electrolyte analyzer having an ion-selective electrode that uses the potential measurement includes: a storage unit that stores the relationship of potential changes over time with respect to interfering ions; and an interfering ion analysis unit that detects the effects of interfering ions based on the potential change over time obtained from the ion-selective electrode while a sample is still in solution after the sample comes into contact with the ion-selective electrode.SELECTED DRAWING: Figure 5

Description

[Technical Field] 【0001】 This invention relates to an electrolyte analyzer. [Background technology] 【0002】 In electrolyte concentration analyzers that analyze using potentiometric measurement, the potential generated at the solid-liquid interface between the ion-sensitive membrane of an ion-selective electrode (ion electrode) and the sample solution (sample) is acquired and converted into concentration for analysis. The potential generated at this solid-liquid interface between the ion-sensitive membrane and the sample solution changes depending on the activity of the target ion in the sample solution (Nernst response). Due to the ease of measurement, ion-selective electrodes are used for electrolyte concentration analysis in liquid samples such as food, industrial water / wastewater, and biological samples. When acquiring the potential, the sample solution is brought into contact with the ion-sensitive membrane of the electrode, and the measurement is taken when the potential stabilizes. 【0003】 Typically, ion-selective electrodes measure only one specific type of ion, and detecting multiple types of ions requires the same number of electrodes. Furthermore, ion-selective electrodes are preferable if their ion selectivity is enhanced to minimize interference from ions other than the target ion. However, improving the ion selectivity of anion-selective electrodes is technically difficult, and they are more susceptible to interference from interfering ions than cationic electrodes. 【0004】 Let's take an electrolyte concentration analyzer installed in an automated biochemical analyzer as an example. Since the samples analyzed are biological samples such as serum, the ion species and ion concentrations in the samples are somewhat fixed, and it is necessary to analyze relatively small differences in ion concentration with high throughput. The three most commonly measured electrolyte parameters in biochemical analysis are Na, K, and Cl ions. 【0005】 For cations such as Na and K ions, ion-sensitive membranes with high ion selectivity are known, making them less susceptible to interference from interfering ions. On the other hand, for anion-selective electrodes such as those for Cl ions, it is technically difficult to create ion-sensitive membranes that are less susceptible to both hydrophilic and lipophilic ions. Therefore, analytical accuracy is improved by devising measurement methods. 【0006】 For example, one calibration method involves using a matrix of samples containing interfering ions under standard conditions. However, even with this method, if the sample contains interfering ions at unusual concentrations or of different types, the influence of the interfering ions may not be canceled out, potentially affecting the ion concentration analysis results. For example, lyophilized control serum (bicarbonate ions (HCO3) - Examples include patient samples with low concentrations of ions, or samples from patients receiving medications containing ions not normally present. 【0007】 Technologies such as those disclosed in Patent Documents 1-3 have been identified as techniques that can handle samples with irregular types and concentrations of interfering ions. 【0008】 Patent Document 1 discloses a technology that includes, in addition to a base electrode which is a chloride ion selective electrode, a first auxiliary electrode which has a larger selectivity coefficient for lipophilic ions than the base electrode, and a second auxiliary electrode which has a larger selectivity coefficient for hydrophilic ions, and an alarm is generated when the measurement value from the auxiliary electrodes is greater than the measurement value from the base electrode and the difference exceeds a set value. 【0009】 Furthermore, Patent Document 2 discloses a technique that "involves bringing a liquid into contact with a plurality of electrodes, each electrode configured to generate a signal in response to sensing selected ions in the liquid; and using a neural network algorithm to calculate ion interference between the selected ions and other ions in the liquid detected by one of the electrodes, and / or electrode interference between the electrodes, based on the results of comparing known ion concentrations with training data representing known ion concentrations; and compensating for the ion interference and / or the electrode interference." 【0010】 Patent Document 3 discloses a technique that "calculates the concentration of a target ion contained in a sample using the results of calculating the selectivity coefficient of an ion-selective electrode and the results of measuring the coexisting ion concentration contained in the sample." [Prior art documents] [Patent Documents] 【0011】 [Patent Document 1] Japanese Patent Publication No. 2000-121595 [Patent Document 2] U.S. Patent Application Publication No. 2013 / 0304395 [Patent Document 3] International Publication No. WO2019 / 163281 Brochure [Overview of the project] [Problems that the invention aims to solve] 【0012】 Conventional techniques have presented challenges in determining the type or concentration of interfering ions. For example, the techniques described in Patent Documents 1 and 2 require measurements using multiple electrodes with different selectivity. Furthermore, Patent Document 3 requires determining the interfering ion concentration using a different analytical method. 【0013】 This invention was made to solve these problems, and one of its objectives is to provide an electrolyte analyzer that can more easily determine the type or concentration of interfering ions. 【0014】 Another objective is to provide an electrolyte analyzer that can make such a determination using a single electrode. [Means for solving the problem] 【0015】 An example of an electrolyte analyzer according to the present invention is: In an electrolyte analyzer having an ion-selective electrode and using potential measurement, It has a memory unit that stores the relationship between interfering ions and changes in potential over time. The system includes an interfering ion analysis unit that detects the influence of interfering ions based on the time-dependent potential change obtained from the ion-selective electrode while the sample is in contact with the ion-selective electrode and the sample is stationary. It is characterized by the following: [Effects of the Invention] 【0016】 The electrolyte analyzer according to the present invention can more easily determine the type or concentration of interfering ions. Furthermore, according to one example, such determination can be made with a single electrode. [Brief explanation of the drawing] 【0017】 [Figure 1] This is a block diagram showing the overall configuration of a flow-type electrolyte concentration measuring device according to Embodiment 1 of the present invention. [Figure 2] This is a flowchart showing the startup process of the apparatus according to Embodiment 1 of the present invention. [Figure 3] This is a flowchart for electrolyte concentration analysis according to Example 1 of the present invention. [Figure 4] This figure shows a typical potential waveform according to Example 1 of the present invention. [Figure 5] This figure shows the potential waveforms when various liquids according to Example 1 of the present invention were measured. [Figure 6] This is a schematic diagram illustrating the phenomenon mechanism used in the present invention. [Figure 7] This is a block diagram of the experimental apparatus for verifying the principle of the present invention. [Figure 8] This figure shows the experimental results obtained using an experimental apparatus for verifying the principle of the present invention. [Figure 9] This is a schematic diagram illustrating the phenomenon mechanism used in the present invention. [Figure 10] This is a flowchart for electrolyte concentration analysis according to Example 2 of the present invention. [Figure 11] This is a flowchart for electrolyte concentration analysis according to Example 3 of the present invention. [Modes for carrying out the invention] 【0018】 The inventors of this invention conducted research and development on methods for detecting and reducing the influence of interfering ions in electrolyte concentration measuring devices in order to achieve more reliable analysis. As a result, they found that it is now possible to detect interfering ions, which were previously difficult to detect, more easily (for example, without installing additional electrodes or sensors). Furthermore, by utilizing this information on interfering ions, they have realized a device that enables more stable analysis. 【0019】 The following describes embodiments of the present invention with reference to the figures. [Example 1] Figure 1 is a schematic diagram showing an example of a flow-type electrolyte concentration measuring device according to Embodiment 1 of the present invention. The electrolyte concentration measuring device 100 is an electrolyte analyzer that has an ion-selective electrode and uses potential measurement. A feature of this embodiment is that the measurement result of the Cl ion electrode, which is an anion, is the target ion to be measured by the electrolyte concentration measuring device 100, and it enables the detection of interfering ions of the anion. 【0020】 The apparatus in this embodiment is a device that analyzes the concentrations of three types of ions: Na, K, and Cl. Along with the analysis results for each ion concentration, it outputs a determination result indicating whether or not the Cl ion concentration measurement was affected by interfering ions. 【0021】 Furthermore, the counterion for the immobilized charge within the sensitive membrane is called the principal ion (Cl ion in the case of a Cl ion electrode), and any ion species other than the principal ion that has the same sign of charge as the principal ion is called an interfering ion. 【0022】 The electrolyte concentration measuring device 100 includes a measuring unit 170, a potential measuring unit 171, a concentration calculation unit 172, an output unit 174, a device control unit 175, an input unit 176, an interfering ion analysis unit 181, and a storage unit 182. 【0023】 The measuring unit 170 is equipped with three types of electrodes as ion-selective electrodes: a Cl ion electrode 101 (chloride ion electrode), a K ion electrode 102 (potassium ion electrode), and a Na ion electrode 103 (sodium ion electrode). It also includes a reference electrode 104. The sensitive membrane of the Cl ion electrode 101 uses an ion-sensitive membrane based on an anion exchange membrane with high density fixed charge. 【0024】 In this embodiment, the ion-selective electrode is a flow-type ion-selective electrode. Using a flow-type ion-selective electrode is preferable because it makes it easier to measure the potential change immediately after the liquid comes to a standstill. 【0025】 Dilution tank 110 temporarily stores a diluted sample, which is a mixture of the sample dispensed from a sample nozzle (not shown) and the diluent dispensed from a diluent supply nozzle 108, or an internal standard solution dispensed from an internal standard solution supply nozzle 109. A sipper nozzle 107 descends into the dilution tank 110, and the diluted sample or internal standard solution in the dilution tank 110 is introduced into the flow path of the ion-selective electrodes (Cl ion electrode 101, K ion electrode 102, and Na ion electrode 103; the same applies hereafter) using a sipper syringe 133. Also, using a sipper syringe, the reference electrode solution is introduced into the flow path of the reference electrode 104 from the reference electrode solution bottle 161. During this time, the diluted sample or internal standard solution remaining in the dilution tank 110 is sucked up by a vacuum suction nozzle 106 that descends, and discharged into the waste liquid tank 111. A vacuum pump 112 is connected to the waste liquid tank 111. 【0026】 Here, we will describe the detailed operation of the mechanism for introducing liquid into the electrode's flow path. First, when introducing the liquid from the dilution tank into the flow path of the ion-selective electrode, solenoid valves 121 and 125 are closed, pinch valves 105 and 122 are opened, the sipper nozzle 107 is lowered into the dilution tank 110, and the sipper syringe 133 is pulled back. Next, when introducing the reference electrode solution into the flow path of the reference electrode 104, solenoid valve 121 is opened, pinch valve 105 is closed, and the sipper syringe 133 is pulled back, thereby introducing the reference electrode solution from the reference electrode solution bottle 161 into the flow path of the reference electrode 104. In addition, to discharge the liquid accumulated in the sipper syringe, solenoid valve 122 is closed, solenoid valve 125 is opened, and the sipper syringe 133 is pushed back. 【0027】 Furthermore, solenoid valves 123, 124, 126, and 127, and an internal standard solution syringe pump 131 are provided. 【0028】 Furthermore, the reference electrode solution introduced into the flow channel of the reference electrode 104 and the solution introduced into the ion-selective electrode come into contact at the liquid junction 120, and the ion-selective electrode and the reference electrode 104 are electrically connected through the liquid. At this time, the electromotive force (potential) between the reference electrode 104 and each ion-selective electrode changes depending on the concentration of the target ion in the solution introduced into the flow channel of the ion-selective electrode. 【0029】 The potential information during this series of analysis operations is acquired by the potential measurement unit 171. The interfering ion analysis unit 181 receives the potential waveform from the potential measurement unit 171 when the liquid is stationary after being introduced into the flow path of the ion-selective electrode, and uses the information stored in the memory unit 182 to perform an analysis on the influence of interfering ions. 【0030】 The concentration calculation unit 172 receives a measurement potential from the potential measurement unit 171 at a stable timing suitable for concentration calculation, and calculates the concentration of the target ion. 【0031】 The output unit 174 displays the operating status of the device received from the device control unit 175, as well as the analysis results from the concentration calculation unit 172 and the interfering ion analysis unit 181. The input unit 176 allows the operator to input sample information, various parameters, and device operation commands. Details of the calculation method will be described later. 【0032】 Next, Figure 2 will be used to explain the startup flow of the electrolyte concentration measuring device 100. First, the startup procedure will be explained. The electrolyte concentration measuring device 100 is started up (S201), electrodes are installed (S202), and reagent bottles are installed (S203). Reagent priming is performed to replace the syringe pump and flow path with new reagents and fill them (S204). Continuous measurement of the internal standard solution is performed to confirm that the electrode potential is stable (S205). In order to determine the calibration curve for each ion-selective electrode, two types of standard solutions of known concentrations are measured and the slope is calculated (S206). Subsequently, the internal standard solution concentration is calculated (S207). 【0033】 Here, the specific operations of S206 and S207 will be described. After dispensing a known low-concentration standard solution into the dilution tank 110 using a dispensing nozzle (not shown), the diluent in the diluent bottle 151 is dispensed into the dilution tank using a diluent syringe pump 132 to dilute the known low-concentration standard solution at the set ratio D. The diluted known low-concentration standard solution in the dilution tank 110 is aspirated from the sipper nozzle 107 and introduced into the flow path of each ion-selective electrode. 【0034】 Subsequently, the reference electrode solution is introduced from the reference electrode solution bottle 161 into the flow path of the reference electrode 104. At the liquid junction, the reference electrode solution and the diluted known low-concentration standard solution come into contact. Immediately after introducing the diluted standard solution into the electrode flow path, and while the liquid is stationary, the electromotive force between each ion-selective electrode and the reference electrode 104 is measured by the potential measurement unit 171. 【0035】 Meanwhile, the remaining liquid in the dilution tank 110 is sucked up with the vacuum suction nozzle 106, and then the internal standard solution from the internal standard solution bottle 141 is dispensed into the dilution tank 110. The internal standard solution from the dilution tank 110 is then sucked up with the internal standard solution from the sipper nozzle 107, filling the channels of each ion-selective electrode with the internal standard solution, and the reference electrode solution from the reference electrode solution bottle 161 is introduced into the channel of the reference electrode 104. 【0036】 Immediately after introducing the internal standard solution into the electrode channel, the electromotive force of each electrode is measured by the potential measurement unit 171 while the solution is stationary. Meanwhile, the remaining liquid in the dilution tank 110 is sucked up with a vacuum suction nozzle, and then the known high-concentration standard solution is dispensed into the dilution tank 110 using a dispensing nozzle (not shown). Finally, the dilution solution in the dilution solution bottle 151 is dispensed into the dilution tank using a dilution solution syringe pump 132, and the known high-concentration standard solution is diluted at the set ratio D. 【0037】 The diluted known high-concentration standard solution in the dilution tank is drawn in through the sipper nozzle and introduced into the flow path of each ion-selective electrode. Then, the reference electrode solution is introduced from the reference electrode solution bottle 161 into the flow path of the reference electrode 104. At the liquid junction, the reference electrode solution and the diluted known high-concentration standard solution come into contact. 【0038】 Immediately after introducing the diluted standard solution into the electrode channel, the electromotive force between each ion-selective electrode and the reference electrode 104 is measured by the potential measurement unit 171 while the liquid is stationary. Meanwhile, the liquid remaining in the dilution tank 110 is sucked up with a vacuum suction nozzle, and then the internal standard solution from the internal standard solution bottle 141 is dispensed into the dilution tank 110. The internal standard solution in the dilution tank is then sucked up with a sipper nozzle to fill the channels of each ion-selective electrode with the internal standard solution, and the reference electrode solution is introduced from the reference electrode solution bottle 161 into the channel of the reference electrode 104. 【0039】 Immediately after introducing the internal standard solution into the electrode channel, the electromotive force of each electrode is measured by the potential measurement unit 171 while the solution is stationary. In addition, the remaining liquid in the dilution tank 110 is sucked up by a vacuum suction nozzle. 【0040】 As described above, in the potential measurement unit 171, for the three types of solutions, i.e., the low-concentration standard solution, the high-concentration standard solution, and the internal standard solution, the potential waveforms during liquid quiescence can be obtained immediately after introduction. The concentration calculation unit 172 receives the potential value (potential difference) in the time region where the potential is most stable among the potential waveforms obtained by the potential measurement unit 171, and uses it as the measured electromotive force (EMF) of each solution. According to the above sequence, the waveform of the internal standard solution is obtained twice. Since the solutions have the same composition, the same value should be obtained in principle. If the same value cannot be obtained, it may be due to the influence of the remaining solution measured immediately before. Correction may be performed using this information during the calculation of the slope sensitivity and the internal standard solution concentration. Also, it can be used as an alarm for the device status and an indicator for the timing of device maintenance. 【0041】 The concentration calculation unit 172 calculates the slope sensitivity SL corresponding to the calibration curve from the electromotive force received from the potential measurement unit 171 using the following formula (1). (A) Slope sensitivity SL=(EMF H -EMF L ) / (LogC H -LogC L ) … Formula (1) 【0042】 However SL: Slope sensitivity EMF H : Measured electromotive force of the known high-concentration standard solution EMF L : Measured electromotive force of the known low-concentration standard solution C H : Known concentration value of the high-concentration standard solution C L : Known concentration value of the low-concentration standard solution 【0043】 The above operations are called calibration. The slope sensitivity SL corresponds to the part of "2.303×(RT / zF)" in the following Nernst equation. Nernst equation: E = E0 + 2.303×(RT / zF)×log(f×C) (where E0: constant potential determined by the measurement system, z: valence of the ion being measured, F: Faraday constant, R: gas constant, T: absolute temperature, f: activity coefficient, C: ion concentration) 【0044】 The slope sensitivity SL can be calculated from the temperature and the valence of the ion being measured, but in this embodiment, in order to improve analytical accuracy, the electrode-specific slope sensitivity SL is determined by the calibration described above. 【0045】 Next, the concentration of the internal standard solution is calculated from the slope sensitivity and the electromotive force of the internal standard solution. (B) Internal standard solution concentration C IS =C L ×10 a … Formula (2) a=(EMF IS -EMF L ) / SL … Equation (3) 【0046】 however C IS :Internal standard solution concentration EMF IS : Electromotive force of the internal standard solution 【0047】 The above describes an example of a specific calibration method, but any other procedure is acceptable as long as it involves introducing two or more solutions with different ion concentrations into the flow path and measuring the electromotive force. Note that the standard solutions may contain interfering ions such as bicarbonate ions. Furthermore, standard samples with compositions similar to serum or urine samples may be measured, and the calibration may be corrected accordingly. 【0048】 After calibration, serum, urine, etc., are used as samples for analysis. Next, Figure 3 will be used to explain the flow of continuous analysis in this embodiment. 【0049】 Specifically, when the measurement operation is started (S301), the internal standard solution from the internal standard solution bottle 141 is dispensed into the dilution tank. The internal standard solution from the dilution tank is drawn in through the sipper nozzle 107, filling the flow path of each ion-selective electrode with the internal standard solution, and the reference electrode solution from the reference electrode solution bottle 161 is introduced into the flow path of the reference electrode 104 (S302). 【0050】 Immediately after introducing the internal standard solution into the electrode flow path, the electromotive force of each electrode is measured by the potential measurement unit 171 while the solution is stationary (S303). Meanwhile, the liquid remaining in the dilution tank 110 is sucked up with a vacuum suction nozzle, the sample is dispensed into the dilution tank 110 with a dispensing nozzle (not shown), and then the diluent from the diluent bottle 151 is dispensed into the dilution tank using the diluent syringe pump 132 to dilute the sample at the set ratio D. 【0051】 The diluted sample in the dilution tank 110 is aspirated through the sipper nozzle and filled into the channels of each ion-selective electrode, and the reference electrode solution is introduced from the reference electrode solution bottle 161 into the channel of the reference electrode 104 (S304). 【0052】 Immediately after introducing the sample into the electrode channel, the electromotive force of each electrode is measured by the potential measurement unit 171 while the liquid is stationary (S305). In addition, the liquid remaining in the dilution tank is sucked up with a vacuum suction nozzle. 【0053】 Next, the concentration calculation unit 172 extracts the potential value for concentration calculation from the potential measurement unit 171 (S306), and calculates the concentration of the sample using the following equations (4) and (5) based on the slope sensitivity and internal standard solution concentration (S308). (C) Concentration of the sample C S =C IS ×10 b … Formula (4) b=(EMF IS -EMF S ) / SL … Equation (5) 【0054】 however C S : Sample concentration EMF S : Electromotive force measured by the sample 【0055】 In this embodiment, the apparatus calculates and corrects the sample measurement based on the measurement potential value of an internal standard solution with a constant concentration, which is measured before the sample measurement. Therefore, accurate measurement can be achieved even if gradual potential fluctuations (potential drift phenomenon) occur due to changes in the membrane surface or temperature. Note that the measurement potentials of the internal standard solution before and after the sample measurement may also be used. 【0056】 Separately, the interfering ion analysis unit 181 extracts a potential waveform for interfering ion analysis from the potential measurement unit 171 (S321). 【0057】 Furthermore, the interfering ion analysis unit 181 extracts a potential waveform for temperature analysis from the potential measurement unit 171 (S331), calculates the temperature effect (S332), and uses the result to correct the temperature effect in the potential waveform for interfering ion analysis extracted in S321 (S322), and calculates the effect of interfering ions (S323). In this way, the interfering ion analysis unit 181 detects the effect of interfering ions based on the time-dependent potential change obtained from the ion-selective electrode while the sample is still in liquid after the sample has come into contact with the ion-selective electrode. 【0058】 The interfering ion analysis unit 181 then displays the interfering ion influence detection results along with the measured ion concentration results on the output unit 174 (S309). In particular, the output unit 174 displays the detection results of the interfering ion influence. This allows the user to know the influence of the interfering ions. 【0059】 If you want to measure the next sample, return to S302; otherwise, end the measurement (S311) (S310). 【0060】 In this embodiment, steps S321 and S331 extract potential waveforms not only during sample measurement but also during internal standard solution measurement, and these waveforms are used to check for fluctuations in the device's state. 【0061】 Here, we will describe the method for calculating the influence of interfering ions. Figure 4 shows the potential waveform over the entire time domain during one cycle of sample solution measurement in this embodiment. The time domain can be mainly divided into (a) when the sample solution is introduced, (b) when the solution is still, (c) when the reference electrode solution is introduced, and (d) when the solution is still. 【0062】 (a) When introducing the sample solution, and (c) when introducing the reference electrode solution, vibrations, liquid flow, and electrical noise are generated due to the operation of solenoid valves, pinch valves, syringe pumps, etc., which disrupts the potential waveform. For the potential waveform (S321) used for interfering ion analysis in this embodiment, the time domains of (b) and (d) when the liquid is stationary are extracted. Note that the potential waveform does not have to be a continuous waveform or a waveform containing values ​​at many time points, but it is sufficient to include potential values ​​at two or more points at different time points when the liquid is stationary. 【0063】 The potential waveform obtained in S321 is subjected to temperature influence correction, as described later. The memory unit 182 stores the correlation between the potential waveform and interfering ions in this time domain. By analyzing the temperature-corrected potential waveform using the information in the memory unit, the influence of interfering ions can be calculated. 【0064】 The memory unit 182 stores the relationship between the potential change over time and the interfering ions. For example, the interfering ion analysis unit 181 identifies the type of interfering ion based on the direction of the change in the potential waveform. As a specific example, if the temporal slope of the potential waveform is positive, Br - SCN - It is determined that lipophilic interfering ions such as HCO3 are present. If the temporal slope is negative, - It is determined that hydrophilic interfering ions are present. In this way, the type of interfering ions can be identified. 【0065】 Furthermore, by comparing the information stored in the memory unit 182, the type or concentration of interfering ions can be estimated from the magnitude of the slope. Also, if the type of interfering ion is known, the interfering ion analysis unit 181 calculates the concentration of the interfering ions based on the slope of the change in the potential waveform, according to the magnitude of the slope. In this way, the concentration of interfering ions can be calculated. 【0066】 The information stored in the memory unit 182 may be the information entered before the device is shipped, but it can also be entered using the input unit 176 to match the device status and electrode characteristics used by the user. 【0067】 For example, the input unit 176 may be used to input information about the sample into the storage unit 182. The information about the sample may represent, for example, the type of drug that may be contained in the sample, and the storage unit 182 may store the type of drug in association with the type of interfering ion contained in that drug. In this way, by inputting the type of drug, the type of interfering ion is identified, so the concentration of the interfering ion can be estimated more accurately. 【0068】 Here, we will explain the hydrophilicity and lipophilicity of ions. The minimum concentration required to salt out proteins differs depending on the ion species, and this permutation is known as the Hofmeister series. Regarding anions, SO4 - >HCO3 - >Cl - >Br - >NO3 - >I - >SCN - The left side is called a hydrophilic ion, and the right side is called a lipophilic ion. Generally, the ion selectivity of a Cl ion electrode tends to increase in the reverse order of the Hofmeister series. In other words, Cl - The more lipophilic side of Br - It is easy to respond to things like Cl - HCO3 on the more hydrophilic side - They tend to be less responsive to such questions. 【0069】 Here, an example of measurement in this embodiment is shown in Figure 5. Several aqueous solutions with different compositions were prepared as simulated samples, and the potential waveforms obtained during measurement are shown. The compositions of the aqueous solutions are as follows: (a)Cl - 100mM (b)Cl- 100 mM + HCO3 - 40mM (c)Cl - 100 mM + HCO3 - 140mM (d)Cl - 100 mM + HCO3 - 40mM + Br - 20mM (e)Cl - 100 mM + HCO3 - 40mM + SCN - 10mM This is the diagram. The vertical axis represents electric potential and the horizontal axis represents time. The time region enclosed by the thick dotted line is the region where the electric potential is unstable due to the operation of the drive mechanism, and the other region is the time region where each liquid is introduced into the electrode channel and the liquid is at rest. 【0070】 As mentioned above, all samples measured here have the same Cl ion concentration. The influence of interfering ions differs depending on the selectivity of each ion in the electrode, and hydrophilic ions such as HCO3 - The impact on Br is relatively small, however - It can be seen that even at low concentrations, it is significantly affected by lipophilic ions such as these. 【0071】 In conventional devices, for example, if the potential for concentration calculation is acquired at 6000ms when the potential is relatively stable, different values ​​are obtained. When the concentration is calculated from this potential, if interfering ions are present, a concentration different from the true value will be output as the Cl ion concentration, but it was not possible to determine whether or not interfering ions were present. Therefore, with conventional devices, the analysis of samples where the interfering ion situation in the blood has changed, such as during medication administration, was avoided. In contrast, in this embodiment, it is possible to output whether or not the calculated Cl ion concentration value was affected by interfering ions and inform the user. 【0072】 This method will now be explained. Figure 5 shows dashed lines drawn horizontally from the potential values ​​at 2000ms for each sample. The deviations from these dashed lines represent the change in potential over time. 【0073】 Looking at the potential at 6000ms, (a) showed almost no deviation from the dashed-dotted line, (b) was slightly lower than the dashed-dotted line, and (c) was significantly lower than the dashed-dotted line. On the other hand, (d) and (e) were higher than the dashed-dotted line. 【0074】 The reason is as follows: (a) is Cl - (b) contains no interfering ions and therefore the potential does not change over time while the liquid is stationary, whereas (b) contains the hydrophilic ion HCO3 - Because it contains 40 mM, it has a slightly negative slope, and (c) is HCO3 - Because it contains 140 mM of , it showed a larger negative slope. On the other hand, (d)(e) is HCO3 - In addition to 40 mM, lipophilic ionic Br - and SCN - Because it contains [a specific element], it showed a positive slope. 【0075】 The memory unit 182 stores information regarding the correlation between ion species, concentration, and potential. The interfering ion analysis unit 181 analyzes the obtained potential waveform, and if the amount of deviation exceeds a certain value, it outputs information about the influence of interfering ions. 【0076】 For example, serum typically contains 30-40 mM HCO3 - Because it contains HCO3, a slope similar to that of the curve in (b) can be used as a reference. Using (b) as a reference, a sample with a slope like (b) is normal, while a sample with a flat waveform like (a) is HCO3 -(c) outputs the possibility that the sample is significantly lower than normal, (b) outputs the possibility that the sample contains an excess of hydrophilic ions, and (e) outputs the possibility that the sample contains lipophilic ions, for samples with a positive slope waveform, as shown in (b) and (e). By looking at these results, the user can examine the characteristics of the sample and simultaneously judge the reliability of the outputted Cl ion concentration analysis value. 【0077】 The reason why the potential changes over time when measuring a sample containing interfering ions in this way will be explained using the schematic diagram in Figure 6. 【0078】 611 and 621 show the ion-sensitive membrane, while 612 and 622 show the sample solution. 610 shows the state immediately after the sample solution is introduced, and 620 shows the state after the solution has settled. 【0079】 The Cl ion-sensitive membrane in this embodiment is based on an ion exchange membrane, and immobilized cations are present in high concentration in the sensitive membrane 611, with Cl acting as a counteranion. - It is present in high concentrations. Therefore, interfering ion J - When in contact with a sample solution containing interfering ions J in the sample solution, - and Cl in the membrane - Rapid ion exchange occurs. This is a characteristic phenomenon that occurs when a film with a high density of fixed charge is used as an ion-sensitive film. 【0080】 For example, HCO3 - When a sample solution containing J is introduced, that is, - is HCO3 - In this case, immediately after introduction, HCO3 in the sample solution - and Cl in the membrane - When an exchange occurs, and the liquid is stationary, the J in the sample liquid near the membrane - Ions are Cl - It will be replaced by ions. 【0081】 Cl ion electrode is HCO3 - More Cl -Because it has higher selectivity and responds more readily to HCO3 in the sample solution present near the film surface, - Cl - When replaced, the Cl ion electrode perceives that the ion concentration of the sample solution has increased. Because the slope sensitivity is negative, the J in the sample solution - Cl - As the exchange reaction progresses, the potential changes in a downward direction. When the same sample solution is reintroduced, the sample solution is refreshed, and the same phenomenon occurs again. 【0082】 HCO3 is also present on the membrane side. - Although it flows in, Cl is present in the membrane. - Because it is present at a high density, the effect on the membrane side is minimal. 【0083】 Also, Br - SCN - When a sample solution containing J is introduced, that is, - ga Br - SCN - In this case, ion exchange occurs between the sample solution and the membrane, but the Cl ion electrode is Cl - More Br - SCN - Because the selectivity for is higher, Br in the sample solution present near the film surface - SCN - Cl - When replaced, the Cl ion electrode perceives a decrease in the ion concentration in the sample solution. Due to its negative slope sensitivity, the potential changes in an upward direction. 【0084】 To more easily understand this phenomenon, we will describe the results of a principle verification using a simple experimental system. A block diagram of the experimental apparatus is shown in Figure 7. The left channel contains a Cl ion electrode 701, and the right channel, accessed via a liquid drop section, contains a reference electrode 702. From the right, the reference electrode solution can be introduced into the reference electrode channel using a syringe 712 filled with the reference electrode solution. From the left, the sample solution can be introduced into the Cl ion electrode channel using a sample solution syringe 711. 【0085】 The procedure involved introducing a liquid, allowing it to stand for approximately 3 minutes, then introducing the next sample liquid and allowing it to stand for another 3 minutes. Throughout the series of measurements, the potential between the Cl ion electrode channel and the reference electrode was continuously measured. 【0086】 Figure 8 shows the potential measurement results in this experiment. The vertical axis represents potential, and the horizontal axis represents time. For NaCl aqueous solutions of different concentrations (1) to (3), all showed stable potential over time, but for (4) 10 mM NaHCO3 aqueous solution, the potential decreased sharply immediately after the liquid stopped moving and then gradually became smoother. (4') When the same concentration of NaHCO3 aqueous solution was introduced again, it started at almost the same potential as (4) and drew a similar curve. (5) When 100 mM NaHCO3 aqueous solution was introduced, the potential changed in a similar negative direction. On the other hand, when (6) 10 mM NaBr aqueous solution was introduced, contrary to the NaHCO3 aqueous solution, the potential increased sharply immediately after the liquid stopped moving and then gradually became smoother. (7) 10 mM NaSCN aqueous solution showed an even more pronounced potential change. (7') When 10 mM NaSCN aqueous solution was introduced again, the phenomenon was reproduced. Finally, when 10 mM NaCl aqueous solutions were introduced into (2') and (2''), they showed almost the same potential as (2). As described above, results were obtained that support the phenomenon explained using Figure 6. 【0087】 Generally, in ion-selective electrodes, it is considered preferable to prevent ion flux generation from the ion-sensitive membrane, as this can lead to a deterioration of the lower limit of the measurable concentration. However, in this embodiment, this phenomenon is utilized in reverse, enabling the detection of not only the target ion concentration but also interfering ions with a single electrode. 【0088】 The conditions under which the above phenomenon occurs will be explained using the schematic diagram in Figure 9. It is believed that two main different phenomena occur depending on the relative magnitudes of the diffusion rates and ion exchange reaction rates within the membrane and in the liquid. These are shown in Figures 910 and 920. 【0089】 Figures 910 and 920 schematically show the changes in interfering ion concentrations within each domain in the case of intramembrane diffusion-limited and boundary layer diffusion-limited ion selection, respectively. The ion-selective electrode has an inner filling solution (IFS), which contains the target ion at a high concentration. Here, "high concentration" means a concentration higher than or equal to the ion concentration contained in the sample solution being measured. 【0090】 In Figure 9, at points 910 and 920, the region enclosed by the two thick vertical solid lines represents the ion-sensitive membrane ("membrane"), with the left side of the membrane representing the sample solution ("sample") and the right side representing the internal solution ("IFS"). 【0091】 The regions near the membrane in both the sample solution and the internal solution, that is, the regions closer to the membrane than the vertical dashed line, are their respective boundary layers. In other words, these are regions where liquid flow does not occur, and only diffusion is predominantly observed. 【0092】 When ion diffusion within the membrane is sufficiently slow compared to ion diffusion in the boundary layer in the liquid, the distribution of interfering ion concentrations is limited by membrane diffusion rate (910). In other words, when a sample solution containing interfering ions comes into contact with the membrane, ion exchange occurs with ions in the membrane. Because diffusion within the membrane is slow, ions on the membrane surface are replaced by interfering ions first. The ratio of this exchange varies depending on selectivity and other factors. Since diffusion in the sample solution is sufficiently faster than diffusion within the membrane, the change in ion concentration in the boundary layer is small. This model is applicable to electrodes containing so-called liquid-film type ion-sensitive membranes made of flexible polyvinyl chloride with quaternary ammonium salts, etc., because the immobilized charge density is low and ion diffusion within the membrane is slow. 【0093】 Meanwhile, within the membrane, diffusion occurs gradually, and the concentration gradient changes in the order x1, x2, x3, and x4, as indicated by the arrows. When interfering ions reach the internal solution, ion exchange occurs between the internal solution and the membrane. Since the internal solution contains sufficient Cl ions and diffusion is sufficiently faster than within the membrane, the ionic composition of the boundary layer of the internal solution hardly changes. Equilibrium is reached after a certain period of time. However, it takes a long time to reach equilibrium. 【0094】 On the other hand, if the ion exchange reaction is sufficiently faster than ion diffusion within the boundary layer, the diffusion-limited process becomes 920. When a sample solution containing interfering ions comes into contact with the membrane, ion exchange occurs with ions in the membrane. Because the membrane has a large ion exchange capacity, and interfering ions taken into the membrane surface diffuse through the membrane, the concentration of interfering ions on the membrane surface hardly increases. 【0095】 On the other hand, because ion diffusion within the boundary layer of the sample solution is slower than in ion exchange reactions, the supply of interfering ions from the bulk layer of the sample cannot keep up, and the concentration of interfering ions in the boundary layer of the sample solution near the membrane gradually decreases in the order of y1, y2, y3, and y4, as indicated by the arrows. In this way, the ion composition ratio of the sample solution near the membrane surface changes until an equilibrium state is reached. In this example, we believe that we are capturing the phenomenon occurring in the boundary layer diffusion-limited manner shown in 920. Note that Figure 9 described above is a schematic representation of the direction of concentration change in each domain, and we believe that the actual profile is not linear. 【0096】 However, even with a diffusion-limited rate of 920 within the boundary membrane, if the ion exchange reaction of the membrane is too fast relative to the interfering ion concentration in the sample solution, the interfering ions in the boundary layer of the sample solution will be depleted instantaneously, making it difficult to detect the change over time depending on the instrument. Conversely, if the ion exchange reaction of the membrane is too slow relative to the interfering ion concentration in the sample solution, the change may be small and difficult to detect. Therefore, by selecting a sensitive membrane with an appropriate ion exchange rate depending on the ion concentration range to be detected and the time scale measured by the instrument, this embodiment can be more easily applied. 【0097】 Preferred conditions for utilizing the principle of this embodiment include: (1) the device being capable of acquiring the potential of the sample solution immediately after introduction and while the solution is stationary within an appropriate time domain; (2) the ion-sensitive membrane of the electrode having a high density of fixed charge; (3) the internal solution containing the target ion at a high concentration; and (4) performing an operation to maintain the ion balance within the membrane periodically (for example, periodically flowing a solution containing the main ion, thereby periodically measuring the solution containing the target ion as shown in Figure 3). 【0098】 In this embodiment, all of the above (1) to (4) are satisfied, and ion-exchange membrane-based ion-sensitive membranes are a more appropriate choice for automated analyzers that need to measure biological samples such as serum at high throughput. 【0099】 The criteria for "high concentration" in (3) can be appropriately determined by a person skilled in the art, but for example, it may be the upper limit of the concentration range of the target ion that is normally expected to be contained in a sample or a higher value, or it may be the upper limit of the concentration range of the target ion that can be measured by the electrolyte concentration measuring device 100 or a higher value. 【0100】 Ion exchange membranes are sometimes referred to as high-capacity ion-exchangers in academic terms because they possess high ion exchange capacity. This high exchange capacity is achieved by using membranes with a high density of fixed charge. In contrast, Cl ion-sensitive membranes with different membrane structures, such as flexible polyvinyl chloride membranes containing common quaternary ammonium salts, do not possess such a high density of fixed charge. Thus, those skilled in the art can clearly determine whether or not a membrane with a high density of fixed charge is used in a sensitive membrane based on the type of membrane, etc. 【0101】 Here, we will describe the method for temperature correction of the potential waveform. When sample solutions at different temperatures are introduced to an ion-sensitive membrane and the solution comes to rest, a temporal slope occurs in the potential waveform depending on the direction and degree of the temperature difference. This temperature difference affects not only the potential of the Cl ion electrode but also the potential of the Na and K ion electrodes. 【0102】 The direction of the temporal change in potential is reversed depending on the sign of the charge of the ion being measured and the direction of the temperature difference, and the degree of this influence varies depending on the thickness of the sensitive film, etc. In this example, when the sample solution temperature is lower than the electrode temperature, the potential of the Cl ion electrode at the time of liquid rest shows a positive slope over time, while the potentials of the Na,K ion electrodes show a negative slope. When the sample solution temperature is higher than the electrode temperature, the opposite trend is observed. 【0103】 Furthermore, since the films of the Na and K ion electrodes in this embodiment are thicker than the films of the Cl ion electrodes, the potential gradient is a certain percentage greater than that of the Cl ion electrode. Information regarding the correlation between the characteristics of the Na, K, and Cl ion electrodes and the potential change due to the effect of temperature differences is stored in the memory unit 182. 【0104】 In S331 of Figure 3, the interfering ion analysis unit 181 extracts the potential waveforms of the Na and K ion electrodes while the liquid is stationary, as measured by the potential measurement unit 171, as potential waveforms for temperature analysis. From the extracted potential waveforms, the degree of influence of the temperature difference during the measurement (for example, the slope of the change in potential over time) is calculated (S332). 【0105】 The temperature effect is corrected from the potential waveform for interference ion analysis using the correlation between the characteristics of each electrode and the temperature difference stored in the memory unit 182 (S322). For example, different coefficients are stored for each ion-selective electrode, and these coefficients are multiplied by the slope of the potential change over time. More specifically, since the change in potential is insensitive to temperature when the film is thin and sensitive when the film is thick, coefficients corresponding to the film thickness can be stored. 【0106】 In this way, the interfering ion analysis unit 181 compares the potential waveform of the ion-selective electrode that responds to the ion to be measured with the potential waveform of the electrode that responds to an ion with a sign opposite to the ion to be measured. Since the Na,K ion electrode is not affected by interference from anions and is also less affected by interference from cations, the temperature effect of the Cl ion electrode's potential waveform can be appropriately corrected by calculating the temperature effect from the potential waveform of the Na,K ion electrode. 【0107】 In electrolyte analyzers for analyzing biological samples, such as the one in this embodiment, the characteristics of the sample to be measured are often known to some extent in advance. By inputting this information beforehand, it becomes possible to improve the accuracy of detecting the influence of interfering ions. 【0108】 For example, serum contains HCO3 -It is common to contain 30 to 40 mM. At the time of calibration, when calibrating in a state containing HCO3 for serum analysis - if calibrated in a state containing HCO3, in the conventional device, when analyzing a control serum or the like that does not contain HCO3 - the Cl concentration becomes low. However, in this example, by inputting specimen information such as serum in advance, when the potential waveform does not have a negative slope, it can be detected that a specimen that does not contain HCO3 such as a lyophilized sample of the control serum may have been measured. - 【0109】 Note that in this example, the sequence is such that it is difficult to obtain the potential waveform during liquid quiescence after introducing the sample solution. However, if the sequence is such that the comparison electrode solution is introduced first and then the sample is introduced, the potential waveform immediately after introducing the sample solution can be obtained with less disturbance, making the analysis easier. 【0110】 Also, it is possible to have a structure different from that of this example for the flow path configuration and the structure of the comparison electrode. Also, the analysis method may be a method different from that of this example, as long as the magnitude and direction of the difference can be obtained from the potentials at two or more different times during liquid quiescence. 【0111】 Also, temperature correction is not necessarily required, and it is not necessary to use the waveform of the internal standard solution as a reference. If the above conditions are satisfied, it is possible to similarly detect the influence of interfering ions for anion electrodes and cation electrodes other than the Cl ion electrode. When detecting the influence of interfering ions on the cation electrode, it is preferable to devise the above-described method of temperature correction. On the other hand, since it is more difficult to fabricate a highly selective sensitive membrane for the anion electrode as described above, it is more valuable to apply it to the anion electrode that is easily affected by interfering ions. 【0112】 As described above, the electrolyte concentration measuring device according to this example can more easily determine the type or concentration of interfering ions. Also, such determination can be made with one electrode. 【0113】 [Example 2] ​The electrolyte concentration measuring device according to Example 2 is different from that of Example 1 in that the result of analyzing the influence of interfering ions is reflected in the Cl ion concentration calculation, and the Cl ion concentration corrected for the influence of interfering ions is calculated. The device configuration and calibration method are the same as those in Example 1. 【0114】 Here, the flow during continuous analysis in the device of this example is shown in FIG. 10. The difference from the flow of Example 1 is that the function stored in the storage unit 182 is fitted to the obtained potential waveform to calculate the influence of interfering ions (S324), and the potential for concentration calculation is corrected using the result (S307). By doing so, it is possible to calculate the Cl ion concentration in a form excluding the influence of interfering ions. 【0115】 In the calculation in this example, S324, S307, and S308 are executed simultaneously. Specifically, in the storage unit 182, as a change model of potential with time for each interfering ion (j), a function F j (C j (C j , t) having concentration (C Cl ) and time (t) as variables is stored. By fitting the potential waveform obtained in S306 to the potential waveform for interfering ion analysis, the Cl ion concentration (C Cl ) and each interfering ion concentration (C j ) are obtained. Expressed by an equation, it becomes as follows in Equation (6) below. E(t)=G(C Cl )+Σ j [F j (C j , t)] … Equation (6) 【0116】 E(t) represents the measured potential waveform, and G(C Cl ) is the value of the potential at a certain Cl ion concentration, with the concentration (C ClThis is expressed as a function with the variable (G(C). Since this does not change over time, the variable for time t is not included. Note that the accuracy of the analysis can be improved by reflecting information such as the slope sensitivity, selectivity, and ion exchange rate of the electrode actually used in these functions. Therefore, the user may input this information into the memory unit 182, or it may be determined in advance by measurement. Characteristics of an ion-selective electrode (for example, G(C) Cl ) and / or function F j (C j The input unit 176 may be used to input ,t)) into the storage unit 182. 【0117】 In this way, the concentration calculation unit 172 calculates the concentration of the target ion by correcting for the influence detected by the interfering ion analysis unit 181. 【0118】 Furthermore, the Cl ion electrode exhibits different potential waveforms depending on the type and concentration of interfering ions in the sample solution, resulting in varying selectivity, partition coefficient, ion exchange reaction rate, and diffusion rate. This difference is utilized in the analysis. On the other hand, certain combinations of ion types and concentrations may produce similar waveforms. In such cases, it becomes difficult to determine the specific type and concentration of the interfering ions. 【0119】 However, in the case of electrolyte analyzers like the one in this embodiment, the characteristics of the sample to be measured are often known to some extent in advance, so by inputting that information beforehand, it is possible to improve the accuracy of calculating the Cl ion concentration and the concentration of interfering ions. 【0120】 For example, serum contains HCO3 - Since it is common for it to contain 30-40 mM, in this embodiment, if sample information that the sample is serum is entered in advance, the potential waveform usually has a negative slope, so HCO3 - This allows for analyses such as prioritizing the fitting of the function. 【0121】 Furthermore, due to drug administration, etc., Br, which is not normally present in the blood, can be produced. -Interfering ions such as those listed above may be present in the sample. In such cases, by pre-entering patient medication information as sample information into the device, waveform analysis can be performed prioritizing the fitting of a function of the interfering ion species corresponding to the drug, thereby improving analytical accuracy. The sample information may, for example, represent the types of drugs that may be present in the sample, and the memory unit 182 may store the types of drugs in association with the types of interfering ions contained in those drugs. 【0122】 By inputting the type of drug, the type of interfering ion can be identified, allowing for a more accurate estimation of the interfering ion concentration. Furthermore, it's possible to calculate not only the Cl ion concentration but also the concentration of interfering ions due to drug administration, potentially serving as an indicator of pharmacokinetics. 【0123】 In this embodiment, the input unit 176 and output unit 174 can be used by the user to directly input information or directly view the output, but they can also be linked with other information systems such as electronic medical records, medication information, and integrated device monitoring systems. 【0124】 As described above, the electrolyte concentration measuring device according to this embodiment, like that of Example 1, can more easily determine the type or concentration of interfering ions. Furthermore, such determination can be made with a single electrode. 【0125】 [Example 3] The configuration of the electrolyte concentration measuring device according to Example 3 differs from that of Example 1 in that, in addition to the Na, K, and Cl ion electrodes, it is equipped with an anion electrode that has different characteristics from the Cl ion electrode. The additional anion electrode has some or all of the following characteristics that differ from the other anion electrodes: ion selectivity, ion exchange reaction rate, ion diffusion coefficient in the sensitive membrane, fixed charge density, type of internal solution, and type of main ion. Thus, the electrolyte concentration measuring device according to this example is equipped with N ion-selective electrodes, each with different characteristics. 【0126】 The number of additional electrodes to be installed varies depending on the number of ion species to be analyzed. In this example, the number of anion electrodes, including the Cl ion electrode, is set to N. In other words, when a sample solution is measured, N different potential waveforms are obtained, depending on the ion species and concentrations contained in the sample solution and the electrode characteristics. 【0127】 Here, Figure 11 shows the flow chart for continuous analysis in this embodiment. We will mainly describe the differences from Figure 10, which is the flow chart for Embodiment 2. 【0128】 For Na and K ion concentrations, the concentration is calculated from the potential at a stable timing, as in Figure 10. However, for anion concentrations, N potential waveforms are extracted from N anion electrodes when the liquid is stationary (S341). Temperature influence correction is performed on these waveforms, as in Example 2 (S342). 【0129】 Subsequently, the type and concentration of anions are calculated by using a time function of the anion species and concentration of each electrode stored in the memory unit, fitting it to the potential waveform of each electrode, and integrating and analyzing all the fitting results (S343). 【0130】 This method makes it possible to determine the concentrations of N or more ions from the potential waveforms obtained from N ion-selective electrodes. Furthermore, it is possible to measure the ion concentrations of N+1 or more ion species based on the time-dependent potential waveforms obtained from N ion-selective electrodes. A specific method for calculating N+1 values ​​based on N waveforms can be appropriately designed by those skilled in the art based on known technology. The analysis method used in S343 is not particularly limited and may include machine learning or neural networks. 【0131】 As described above, the electrolyte concentration measuring device according to this embodiment, like those in Examples 1 and 2, can more easily determine the type or concentration of interfering ions. 【0132】 The present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are explained in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. [Explanation of Symbols] 【0133】 100...Electrolyte concentration measuring device (electrolyte analyzer) 101…Cl ion electrode (ion-selective electrode) 102...K ion electrode (ion-selective electrode) 103…Na ion electrode (ion-selective electrode) 104...Reference electrode 105... Pinch valve 106... Vacuum suction nozzle 107... Sipper nozzle 108...Diluent supply nozzle 109...Internal standard liquid supply nozzle 110...Dilution tank 111...Waste liquid tank 112... Vacuum pump 120...Liquid junction 121-127... Solenoid valve 131... Syringe pump for internal standard solution 132... Syringe pump for diluent 133... Sipper syringe 141... Internal standard solution bottle 151... Diluent bottle 161... Comparison electrode solution bottle 170…Measurement part 171...Potential measurement section 172...Concentration calculation section 174...Output section 175...Device Control Unit 176...Input section 181... Interference Ion Analysis Department 182...Storage section 611... Sensitive membrane 701…Cl ion electrode (ion-selective electrode) 702...Reference electrode 711... Syringe for sample solution 712... Syringe 910...Membrane diffusion-limited rate 920...Diffusion-limited within the boundary membrane

Claims

[Claim 1] In an electrolyte analyzer having an ion-selective electrode and using potential measurement, It has a memory unit that stores the relationship between interfering ions and changes in potential over time. After the sample comes into contact with the ion-selective electrode, the system includes an interfering ion analysis unit that detects the influence of interfering ions in the sample based on the time-dependent potential change obtained from the ion-selective electrode while the sample is still in liquid state. The sensitive membrane of the ion-selective electrode includes an ion exchange membrane. The ion being measured is the Cl ion. An electrolyte analyzer characterized by the following features. [Claim 2] The electrolyte analyzer according to claim 1, characterized in that the interfering ion analysis unit identifies the type of interfering ion in the sample based on the direction of change in the potential waveform. [Claim 3] The electrolyte analyzer according to claim 1, characterized in that the interfering ion analysis unit calculates the concentration of the interfering ion in the sample based on the slope of the change in the potential waveform. [Claim 4] The aforementioned electrolyte analyzer has a concentration calculation unit that calculates the concentration of the ion to be measured. The concentration calculation unit calculates the concentration of the target ion by correcting for the influence detected by the interfering ion analysis unit. The electrolyte analyzer according to claim 1, characterized in that... [Claim 5] The aforementioned interfering ion analysis unit is The potential waveform of the ion-selective electrode, The potential waveform of the electrode that responds to an ion with a sign opposite to the ion being measured, The electrolyte analyzer according to claim 1, characterized by comparing the following. [Claim 6] The electrolyte analyzer according to claim 1, characterized in that the ion-selective electrode is a flow-type ion-selective electrode. [Claim 7] The electrolyte analyzer according to claim 1, characterized in that the ion-selective electrode has an internal solution, and the internal solution contains the ion to be measured. [Claim 8] The electrolyte analyzer according to claim 1, characterized in that it periodically measures a liquid containing the target ion. [Claim 9] The electrolyte analyzer according to claim 1, characterized in that it has an output unit that displays the detection result of the influence of the interfering ions. [Claim 10] The electrolyte analyzer according to claim 1, characterized in that it has an input unit used to input the characteristics of the ion-selective electrode into the memory unit. [Claim 11] The electrolyte analyzer according to claim 1, characterized in that it has an input unit used for inputting information about the sample into the storage unit.

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