JP2000121595A - Ion concentration measurement system and measurement unit used for the same - Google Patents

Abstract

(57) [Problem] To provide an ion concentration measurement system capable of preventing erroneous diagnosis due to a correct error caused by interfering ions coexisting in a sample. A base electrode that is a chloride ion selective electrode.
In addition to 4a, a first auxiliary electrode 14b having a larger selectivity coefficient for lipophilic ions than the base electrode 14a and a second auxiliary electrode 14c having a larger selectivity coefficient for ions more hydrophilic than the base electrode 14a are provided. I have. Judgment means 2
When the value of 0 is determined that the measured value of the auxiliary electrodes 14b and 14c is larger than the measured value of the base electrode 14a and that the difference exceeds the set value, an alarm is generated from the output means 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion concentration measuring system and a measuring unit used for the same, and more particularly, to an ion concentration measuring system suitable for use in an ion concentration measuring device and a clinical biochemical automatic analyzer, and an ion concentration measuring system suitable for use in the system. It relates to the measuring unit used.

[0002]

2. Description of the Related Art Conventionally, in ion concentration measuring systems such as an ion concentration measuring device and a clinical biochemical automatic analyzer, an ion selective electrode is used as a detector. As ion-selective electrodes, cation-selective electrodes such as sodium-selective electrodes and potassium-selective electrodes, and anion-selective electrodes such as chloride-selective electrodes are known. Here, unlike the cation-selective electrode, the chloride-selective electrode for biochemical examination, which is an anion-selective electrode, is roughly classified into two types: a quaternary ammonium salt type and a solid electrode type such as silver / silver chloride. Classified into types.

[0003]

However, in conventional chloride-selective electrodes for biochemical examinations, which are conventional anion-selective electrodes, chloride-selective electrodes having sufficient selectivity for clinical tests are practically used. It has not been converted.

In the case of an ion-selective electrode using a quaternary ammonium salt as a ligand, the selectivity is determined in the reverse order to the order called the elution order (formula (1)) depending on the degree of hydration of the ions.

[0005] _{^{SCN - <I - <ClO 3}} - <NO 3 - <Br - <Cl - <CH 3 COO - <SO 4 2- < tartaric <citric acid (1), such as serum or plasma in a biological sample When measuring the chloride ion concentration, these biological samples often contain interfering ions of anions other than chloride ions.
For example, bicarbonate ions (HC) are generally contained in the blood of the human body.
O ₃ ^-) are included. Also, in the smoker's blood,
Thiocyanate ion (SCN ⁻ ) is contained. Further, in a drug dosing's blood, bromine ion (Br ^-)
May be included. Of these, bicarbonate (HCO ₃ ⁻ ) is a more hydrophilic ion than chloride, and thiocyanate (SCN ⁻ ) and bromide (Br ⁻ ) are more lipophilic than chloride. .

Here, if the selectivity of ions that are more lipophilic than chloride ions is improved, the selectivity of ions that are more hydrophilic than chloride ions becomes worse. There is a tendency for the selectivity of lipophilic ions to be lower than that of ions. Therefore, until recently, when measuring chloride ions in a biological sample such as serum or urine, there has been a problem that a correct error occurs in the measured value due to coexisting interfering ions.

An object of the present invention is to provide an ion concentration measuring system capable of preventing erroneous diagnosis due to a correct error caused by interfering ions coexisting in a sample.

[0008]

(1) In order to achieve the above object, the present invention provides an ion concentration measuring system for measuring an ion concentration using an anion selective electrode. A first auxiliary electrode comprising a base electrode, an anion-selective electrode having a higher selectivity for lipophilic ions than the base electrode, and an anion selectivity having a higher selectivity for ions more hydrophilic than the base electrode A second auxiliary electrode composed of an electrode, and the anion concentration is measured using the base electrode and the first and second auxiliary electrodes. With such a configuration, erroneous diagnosis due to a correct error caused by interfering ions coexisting in the sample can be prevented by using two auxiliary electrodes in addition to the base electrode.

(2) In the above (1), preferably,
The base electrode and the first and second auxiliary electrodes measure a chlorine ion concentration in a biochemical test.

(3) In the above (1), preferably,
Further, a determination means for determining that the measured value of the first or second auxiliary electrode is a value larger than the measured value of the base electrode and that the difference exceeds a set value,
An alarm is generated by the output of the determination means. With this configuration, when the measured value of the auxiliary electrode is too large, it is determined that the influence of the interfering ions is large, and an alarm is generated, thereby causing a misdiagnosis due to a correct error caused by the interfering ions coexisting in the sample. Can be prevented.

(4) In the above (3), preferably,
The determination means is configured to determine whether a difference between the measured values of the first or second auxiliary electrode and the base electrode does not exceed a set value.
An output indicating that the reliability of the measured value is high is output. With this configuration, it is possible to ensure the reliability of the measured value by displaying that the reliability of the measured value is high.

(5) In the above (3), preferably,
The determining means selects and outputs a minimum value from the measured values of the first and second auxiliary electrodes and the base electrode. With such a configuration, it is possible to output a measurement value that is less affected by interfering ions.

(6) In the above (1), preferably,
And a correction means for correcting the measurement value of the base electrode based on the difference between the measurement value of the base electrode and the first and second auxiliary electrodes, and outputting the correction value of the correction means. It is something to do. With such a configuration, the effect of the interfering ions can be corrected.

(7) In order to achieve the above object, the present invention relates to a measurement unit for measuring an ion concentration in which an anion selective electrode or an anion selective membrane is incorporated.
A first auxiliary electrode comprising an anion-selective electrode or an anion-selective membrane having a larger selectivity coefficient for lipophilic ions than the base electrode, and And a second auxiliary electrode comprising an anion-selective electrode or an anion-selective membrane having a larger selectivity coefficient for ions more hydrophilic than the base electrode.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of an ion concentration measuring system according to an embodiment of the present invention will be described below with reference to FIGS. First, the overall configuration of the ion concentration measurement system according to the present embodiment will be described with reference to FIG.

The measuring unit 10 is composed of a base electrode 14a, which is a chlorine ion selective electrode for biochemical tests, incorporated in the block 12, and auxiliary electrodes 14b, 14c. The auxiliary electrode 14b is an ion-selective electrode that has a lower selectivity for lipophilic ions than chloride ions and a better selectivity for ions that are more hydrophilic than chloride ions as compared to the base electrode. Conversely, the electrode 14c
Is an on-selective electrode that has poorer selectivity for ions that are more hydrophilic than chloride ions compared to the base electrode, and has better selectivity for ions that are more lipophilic than chloride ions than the base electrode. When thiocyanate ion (SCN ⁻ ) is selected as an index of lipophilic ion from chlorine ion and bicarbonate ion (HCO ₃ ⁻ ) is selected as an index of hydrophilic ion from chloride ion, selection of each electrode 14a, 14b, 14c The coefficient is
The one shown in (Table 1) is used.

[0017]

[Table 1]

The measured values measured by the electrodes 14a, 14b, 14c are input to the judgment means 20 and the correction means 30, respectively. The judging means 20 compares the value measured by the base electrode 14a with the value measured by the auxiliary electrodes 14b and 14c, and outputs an alarm from the output means 40 when the difference is larger than a predetermined value. I do. The correcting unit 30 corrects the value measured by the base electrode 14a with the value measured by the auxiliary electrodes 14b and 14c, and outputs the corrected value from the output unit 40. The detailed operations of the determination unit 20 and the correction unit 30 will be described later with reference to FIG.

Next, a first determination process of the determination means 20 according to the present embodiment will be described with reference to FIG. FIG.
5 is a flowchart showing a first determination process performed by a determination unit used in the ion concentration measurement system according to the embodiment of the present invention.

In step 100, the judgment means 20
Before the sample measurement, an allowable range B0 (mmol / l) of the difference between the measured value of the base electrode 14a and the measured value of the auxiliary electrode 14b is set, and the measured value of the base electrode 14a and the measured value of the auxiliary electrode 14c are set. Set the allowable range of difference C0 (mmol / l). For example,
Prior to the measurement of the sample, B0 = 5 mmol / l and C0 = 4 mmol / l. Next, in step 110, the judgment means 20
Indicates that the base electrode 14a and the auxiliary electrode 14
The difference ΔB between the measured values of b and the difference ΔC between the measured values of the base electrode 14a and the auxiliary electrode 14c are calculated.

In step 120, the determination means 20 determines whether the difference ΔB between the measured values and the difference ΔC between the measured values are smaller than the set values B0 and C0. If any of them is smaller than the set value, the process proceeds to step 130; otherwise, the process proceeds to step 140. Difference of measured value Δ
If B and ΔC are smaller than the set values B0 and C0, in step 130, the determination means 20
And outputs the measured value by the base electrode 14a without outputting an alarm. For example, ΔB = 2 mmol / l, ΔC
If = 1.5 mmol / l, output data without alarm.

On the other hand, if the difference ΔB or ΔC between the measured values is larger than the respective set values B 0, C 0, in step 140, the judging means 20 proceeds to steps 150, 160, 170 according to the respective magnitude relations. Advance, 3
Displays the type of alarm. That is, the measured value difference ΔB is equal to or greater than the set value B0, and the measured value difference ΔC is equal to or greater than the set value C0.
If it is smaller, in step 150, the determination means 20 displays an alarm indicating “interference of lipophilic ions” from the output means 40. For example, ΔB = 7 mmol / l, ΔC =
In the case of 1.5 mmol / l, an alarm is displayed as "interference of lipophilic ions".

If the difference ΔB between the measured values is equal to or greater than the set value B 0 and the difference ΔC between the measured values is equal to or greater than the set value C 0, in step 160, the judgment means 20 outputs Interference with lipophilic and hydrophilic ions "
Alarm display. Further, when the difference ΔB between the measured values is smaller than the set value B0 and the difference ΔC between the measured values is equal to or larger than the set value C0, in step 170, the determination means 2
0 indicates an alarm display of "interference of hydrophilic ions" from the output means 40.

As described above, the differences ΔB and ΔC between the measured values
When the value exceeds the set values B0, C0, that is, when the influence of the interfering ions in the sample exceeds a certain value, an erroneous diagnosis due to the deviation on the high value side can be prevented by displaying an alarm. The reason why the measured value shows an abnormal value is not only the influence of interfering ions, but also an abnormal device such as air noise caused by air entering the sample flow path. By displaying the influence of ions, the operator can easily be notified of an abnormal value due to a device abnormality or an abnormal value due to interfering ions.

Further, the content of the second determination processing of the determination means used in the ion concentration measurement system of the present embodiment is as follows. The determination means 20 determines whether the measured value of the base electrode 14a and the measured value of the auxiliary electrode 14b are measured before the sample measurement. Two allowable ranges of difference B0
1, B02 (mmol / l) is set, and two allowable ranges C0 of the difference between the measured value of the base electrode 14a and the measured value of the auxiliary electrode 14c are set.
1, Set C02 (mmol / l). For example, before measurement of a sample, B01 = 3 mmol / l, B02 = 6 mmol / l, C01 = 2 mmol
Set l / l and C02 = 5 mmol / l.

If the difference ΔB, ΔC between the measured values is smaller than the first set values B01, C01, the judgment means 20
Outputs the value measured by the base electrode 14a from the output means 40 and displays "highly reliable" on the data. For example, ΔB = 2 mmol / l, ΔC =
A 1.5 mmol / l sample is indicated in the data as "highly reliable".

The differences ΔB and ΔC between the measured values are smaller than the second set values B02 and C02, and the first set values B01 and C01.
If any of the values is larger than the above, the determination means 20 outputs the measurement value of the base electrode 14a from the output means 40. At this time, it is assumed that the display such as "high reliability" is not displayed.

Further, if any of the differences ΔB and ΔC of the measured values is larger than the second set values B02 and C02, the judging means 20 outputs the measured value of the base electrode 14a from the output means 40. At the same time, "large disturbance" is displayed for the data. Further, the difference ΔB between the measured values is
Is larger than the set value B02, "Large interference of lipophilic ions" is displayed, and the difference ΔC between the measured values is equal to the second set value C02.
If it is larger than 02, it may be displayed as "large interference of hydrophilic ions".

As described above, the difference ΔB, ΔC between the measured values
Is lower than the first set values B01, C01, that is, when the influence of the interfering ions in the sample is equal to or less than a certain value, "reliable" is displayed, so that the data is highly reliable. Can be notified.

Next, a first correction process of the correction means 30 according to the present embodiment will be described with reference to FIG. FIG.
5 is a flowchart showing a first correction processing content of a correction unit used in the ion concentration measurement system according to one embodiment of the present invention.

In step 200, the correcting means 30
Captures the measured value A of the base electrode 14a, the measured value B of the auxiliary electrode 14b, and the measured value C of the auxiliary electrode 14c. Then, in step 210, the correction means 30 compares these measured values A, B, and C with each other. If the measured value A is the minimum, the process proceeds to step 220, where the output means 40 outputs the measured value A. If the measured value B is the minimum, proceed to step 230,
In step 230, the measured value B is output from the output means 40. When the measured value C is the minimum, the process proceeds to step 240, and the measured value C is output from the output means 40 in step 240.

Here, the results of measurement using a test sample by the first correction method according to the present embodiment will be described with reference to (Table 2).

[0033]

[Table 2]

The experimental samples shown in Table 2 contain a chloride ion concentration of 100 mmol / l as a base.
With respect to the base, for example, Sample 1 contains thiocyanate ion (SCN ⁻ ) as an interfering ion at 0.5 mmol / mol.
l, bicarbonate ion (HCO ₃ ⁻ ) was co-existed at 100 mmol / l, and the specimen 2 was 0.5 mmol / l thiocyanate ion (SCN ⁻ ) as an interfering ion, and bicarbonate ion (HCO ₃ ⁻ ) ₃ ^-) and is obtained by co 20 mmol / l. Similarly, the other specimens 3 to 9 also contain the coexisting ions shown in (Table 2). The selection coefficients of the base electrode 14a and the auxiliary electrodes 14b and 14c, which are the ion selective electrodes used, are as shown in (Table 2), and are the same as those shown in (Table 1).

As for the samples 1 to 6 and the samples 8 and 9, the measured value of the base electrode 14a was minimized.
By the processing in step 220, the measurement value of the base electrode 14a is output from the output means 40. Further, for the sample 7, the measured value of the auxiliary electrode 14b is minimized, and thus the measured value of the auxiliary electrode 14b is output from the output unit 40 by the process of step 230. That is, when the interference of the lipophilic ions is very small, the measured value of the auxiliary electrode 14b becomes the minimum value. Similarly, when the interference of the hydrophilic ions is very small, the measured value of the auxiliary electrode 14c becomes the minimum value, and the measured value of which the influence of the interfering ions is smaller than that of the base electrode 14a is obtained.

As described above, by comparing the measured values of the base electrode 14a and the auxiliary electrodes 14b and 14c and outputting the smallest measured value, the measured value with the smallest interference by the interfering ions is output. And the effect of interference can be reduced.

Next, a second correction process of the correction means 30 according to the present embodiment will be described. In the present embodiment, the concentration is corrected using the following correction formula (2), with the specific lipophilic ion being thiocyanate ion and the specific hydrophilic ion being bicarbonate ion.

Corrected concentration = A−ΔB × KAL / (KBL−KAL) −ΔC × KAH / (KCH−KAH) (2) where A: measured value of base 14a electrode ΔB: auxiliary electrode 14b ΔC: Difference between the measured values of the auxiliary electrode 14c and the base electrode 14a KAL: Selection coefficient for the specific lipophilic ion of the base electrode 14a KBL: Selection coefficient for the specific lipophilic ion of the auxiliary electrode 14b KAH : Selectivity coefficient for specific hydrophilic ions of base electrode 14a KCH: Selectivity coefficient for specific hydrophilic ions of auxiliary electrode 14c

Here, the results of measurement using the test sample by the second correction method according to the present embodiment will be described with reference to Table 3.

[0040]

[Table 3]

The experimental samples shown in Table 3 are shown in Table 2
Similarly, as a base, the chloride ion concentration is 100
m mol / l. For that base, for example,
Specimen 1 contains thiocyanate ion (S
CN ^-) to 0.5 m mol / l, bicarbonate ions (HCO ₃ ^- are those of) coexists 100 m mol / l, the specimen 2, as an interfering ion, thiocyanate ion (SCN ^- 0 a).
5 mmol / l and bicarbonate ion (HCO ₃ ⁻ ) were present at 20 mmol / l. In the same manner, for the other specimens 3 to 9,
It contains the coexisting ions shown in (Table 3). Also,
The selection coefficients of the base electrode 14a and the auxiliary electrodes 14b and 14c, which are the ion-selective electrodes used, are as shown in (Table 3) and are the same as those shown in (Table 1).

For example, for the sample 1, the correction equation (2)
By using, the correction density = 115− (151−115) × (10) /
(100-10)-(151-115) x (0.1) /
(0.5−0.1) = 102.

As described above, for each of the specimens 2 to 9, the result of the correction using the correction equation (2) is as follows.
As shown in Table 3 as a correction value, the value is closer to the true value than the value measured at each electrode, and indicates that correction is possible when a dominant interfering ion species can be predicted. Generally, the blood of the human body contains bicarbonate ions (HCO ₃ ⁻ ), and the blood of smokers contains thiocyanate ions (SCN ⁻ ). By performing correction as a seed, correction can generally be performed. In addition, the bromine ion (B
r ^-) when it is known that contain the bromide ion (Br - as interfering ions ^species), it can be corrected using the same correction equation (2).

Next, the configuration of an ion concentration measuring system according to another embodiment of the present invention will be described with reference to FIG. The measurement unit 10A is composed of a base electrode 14A, which is a chlorine ion selective integrated electrode for biochemical testing, incorporated in the block 12A, auxiliary electrodes 14B, 14C, and silver / silver chloride internal electrodes 16A, 16B, 16C. It is configured. The auxiliary electrode 14B is an ion-selective integrated electrode that has a lower selectivity for lipophilic ions than chloride ions than the base electrode 14A, and has a higher selectivity for ions that are more hydrophilic than chloride ions as compared to the base electrode 14A. Conversely, the electrode 14C is an on-selective integrated electrode that has a lower selectivity for ions that are more hydrophilic than chloride ions compared to the base electrode 14A, and has a higher selectivity for ions that are more lipophilic than chloride ions than the base electrode 14A. Select, bicarbonate ion as an indicator of the hydrophilic ion than chloride ion - ^(Br) bromide from chloride ion as an indicator of lipophilic ion (HCO ₃ ^-) If you choose, the electrodes 14A, 14
As the selection coefficients of B and 14C, those shown in (Table 4) are used.

[0045]

[Table 4]

The measured values measured by the electrodes 14A, 14B, 14C are input to the judgment means 20 and the correction means 30, respectively, as in FIG.

Here, using the measuring unit 10A using the ion-selective integrated electrode having the configuration shown in FIG. 4, the washing water after washing in the factory production line is measured as a sample, and the measurement is performed on the factory production line. Was monitored to see if it satisfied the specifications. As a result of measuring the concentration of the sample, when the chloride ion concentration is 0.05 mmol / l, the auxiliary sensitive membrane 1
The measured value of 4B was 0.05 mmol / l, and the difference was less than 0.001 mmol / l compared to the value of the base sensitive film 14A. The measured value of the auxiliary sensitive film 14C is 0.08
mmol / l, which is 0.1% compared to the value of the base sensitive film 14A.
It could be monitored that the concentration was higher than 03 mmol / l, the chlorine ion remained much, and the hydrophilic anion remained larger than the chloride ion.

As described above, according to the present embodiment, by using two auxiliary electrodes having different selectivity in addition to the anion-selective base electrode, the influence of interfering ions can be reduced, and Can be prevented from being misdiagnosed due to a correct error caused by coexisting interfering ions. In addition, it is possible to judge whether the high value deviation is caused by lipophilic ions or hydrophilic ions rather than chloride ions, and display the result as an alarm to indicate which ion is used, thereby helping to identify the cause of the measurement value deviation. it can.

[0049]

According to the present invention, it is possible to prevent erroneous diagnosis due to a correct error caused by interfering ions coexisting in a sample in an ion concentration measuring system.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an ion concentration measurement system according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a first determination process performed by a determination unit used in the ion concentration measurement system according to the embodiment of the present invention;

FIG. 3 is a flowchart illustrating a first correction process performed by a correction unit used in the ion concentration measurement system according to the embodiment of the present invention;

FIG. 4 is a block diagram showing a configuration of a second measurement unit used in an ion concentration measurement system according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 Measurement unit 12 Block 14a Base electrode 14b Auxiliary electrode (lipophilic) 14c Auxiliary electrode (hydrophilic) 14A Base sensitive film 14B Auxiliary sensitive film (lipophilic) 14C Auxiliary sensitive film (hydrophilic) 16 internal electrode 20 determination means 30 correction means 40 output means

Claims (7)

[Claims] 1. An ion concentration measuring system for measuring an ion concentration using an anion-selective electrode, wherein the anion-selective electrode is used as a base electrode, and a negative electrode having a larger selection coefficient for lipophilic ions than the base electrode. A first auxiliary electrode composed of an ion-selective electrode; and a second auxiliary electrode composed of an anion-selective electrode having a larger selectivity coefficient for ions more hydrophilic than the base electrode, wherein the base electrode and the first And an ion concentration measuring system using the second auxiliary electrode to measure an anion concentration. 2. The ion concentration measuring system according to claim 1, wherein the base electrode and the first and second auxiliary electrodes measure a chloride ion concentration in a biochemical test. 3. The ion concentration measuring system according to claim 1, further comprising: a value measured by said first or second auxiliary electrode is a value larger than a value measured by said base electrode, and a difference between the measured values is a set value. The ion concentration measurement system further comprises: a determination unit that determines that the value exceeds the threshold, and an alarm is generated based on an output of the determination unit. 4. The ion concentration measuring system according to claim 3, wherein said determining means is configured to determine whether a difference between a measured value of said first or second auxiliary electrode and said measured value of said base electrode does not exceed a set value.
An ion concentration measurement system, which outputs an output indicating that the reliability of a measured value is high. 5. The ion concentration measuring system according to claim 3, wherein said determining means selects and outputs a minimum value from the measured values of said first and second auxiliary electrodes and said base electrode. An ion concentration measurement system characterized by the following. 6. The ion concentration measurement system according to claim 1, further comprising: a measurement value of the base electrode based on a difference between the measurement value of the base electrode and the first and second auxiliary electrodes. An ion concentration measurement system, comprising: a correction unit that corrects the correction value; and outputting a correction value of the correction unit. 7. A measurement unit for measuring an ion concentration in which an anion-selective electrode or an anion-selective membrane is incorporated, wherein the anion-selective electrode or the anion-selective membrane is used as a base electrode. A first auxiliary electrode consisting of an anion-selective electrode or an anion-selective membrane having a large selectivity for lipophilic ions; and an anion-selective electrode having a large selectivity for ions more hydrophilic than the base electrode or A second auxiliary electrode comprising an anion-selective membrane.