JPH04177165A - Method for measuring concentration of ion - Google Patents

Abstract

PURPOSE:To measure the amount of the electrolyte in a solution to be examined by bringing an ion exchanger having a coloring substance or color substance bonded thereto by an ionic bond into contact with the solution to be examined and detecting the coloring substance or color substance separated from the ion exchanger. CONSTITUTION:At first, a coloring substance or color substance is bonded to an ion exchanger by an ionic bond. Next, the ion exchanger subjected to the ionic bond is put in a container such as a test tube. Next, when a specimen such as urine is charged in the container, the electrolyte in the solution to be examined is subjected to the ion exchange with the coloring substance or color substance. Since the amount of the coloring substance or color substance separated from the ion exchanger is almost proportional to the amount of the electrolyte present in the solution to be examined, the color intensity of the solution in the container is measured to measure the concn. of the ion in the solution to be examined.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an ion concentration measuring method for measuring ion concentration in a test liquid.

<Prior Art> Measurement of the specific gravity of a solution is often performed in the food industry, fermentation industry, and clinical testing fields.

For example, in the field of clinical testing, kidney disease is diagnosed by measuring urine specific gravity.

Urine specific gravity indicates the amount of solute in urine, and its value is known to show a good correlation with ion concentration and osmotic pressure in urine. Normally, the urine specific gravity of a healthy person is 1.016.
~1.022, but if the value is smaller than this range, there is a suspicion of flexor myopathy, acute renal failure, nephritis, etc.
On the other hand, if it is large, nephrotic syndrome, various types of water loss, etc. may be considered.

Such urine specific gravity has conventionally been measured using a pycnometer, a hydrometer (floating scale), or the like, or a urine refractometer or osmometer that correlates with urine specific gravity.

However, these methods, which use pycnometers, hydrometers, etc., require expensive measuring instruments, must use instruments that are difficult to break, and require complicated operations. I had this problem.

In order to solve such problems, the following techniques have been disclosed.

1) At least an effective number of membranes containing a substance capable of producing a detectable response that is a function of the specific gravity or osmolality of the liquid and having walls of a polymeric membrane that are brittle and translucent to osmotic pressure. The specific gravity of a test liquid consisting of microcapsules that releases the enclosed contents through the membrane wall and produces a detectable response when a certain osmotic pressure gradient is generated inside and outside the capsule. Or a composition for measuring osmolality and a measuring instrument using the composition (Japanese Patent Publication No. 60-4637)
No. 4).

2) A liquid sample consisting of a weakly acidic or weakly basic polyelectrolyte and a pH-supporting substance capable of producing a detectable response to ion exchange between the electrolyte and the sample to be tested. Composition for measuring ionic strength (Japanese Patent Publication No. 62-12858).

3) A test layer containing a wettable substance that exhibits a water absorption amount that corresponds to the ionic strength of the aqueous solution and a water absorption indicator that causes a change in transparency by exhibiting a solubility that corresponds to the fluctuation range of the water absorption amount, and the optical properties of the test layer. A specific gravity test tool for aqueous solution samples consisting of a support that serves as a background for
No. 462).

However, the methods using 1), 2), and 3) above all require expensive equipment, facilities, and chemicals, resulting in high costs, and the measurement work is complicated and time-consuming. There is a problem that sufficient accuracy cannot be obtained.

<Problems to be Solved by the Invention> An object of the present invention is to provide an ion concentration measuring method that can quickly and accurately measure the ion concentration in a test liquid with simple operations.

<Means for Solving the Problems> Such objects are achieved by the present invention described in (1) to (11) below.

(1) Bringing an ion exchanger to which a colored or color-forming substance is ionically bonded into contact with a test liquid to ion-exchange the electrolyte present in the test liquid with the coloring or color-forming substance; A method for measuring ion concentration, characterized in that the amount of electrolyte in the test liquid is measured by detecting a colored or colored substance released from an ion exchanger.

(2) The ion concentration measuring method according to (1) above, wherein the ion exchanger is an ion exchange resin.

(3) The ion concentration measuring method according to (1) or (2) above, wherein the ion exchanger is in the form of particles.

(4) The method for measuring ion concentration according to any one of (1) to (3) above, wherein the pre-coloring or coloring substance has excellent solubility or dispersibility.

(5) The colored or color-forming substance is one that has excellent solubility stability with respect to the ion concentration in the solution (1) above.
The ion concentration measuring method according to any one of (3) to (3).

(6) The coloring or coloring substance is at least one selected from the group consisting of azo dyes, anthraquinone dyes, triphenylmethane dyes, oxazine dyes, and thiazine dyes (1) to (5) above. The ion concentration measuring method according to any one of.

(7) The colored or coloring substance includes tartrazine, acid blue 92, acid blue 45, acid blue 129, basic blue 3, basic red 29,
The method for measuring ion concentration according to any one of (1) to (6) above, wherein the ion concentration is at least one selected from the group consisting of basic fuchsin and methylene blue.

(8) The ion concentration measuring method according to any one of (1) to (7) above, in which the colored or colored substance is detected optically.

(9) Decompose the non-electrolyte present in the test solution to obtain an electrolyte, and measure the total electrolyte amount of this electrolyte and the electrolyte originally present in the test solution (1) to (8) above. The ion concentration measuring method according to any one of the above.

(IO) The ion concentration measuring method according to any one of (1) to (9) above, wherein the test liquid is urine.

(11) The ion concentration measuring method according to any one of (1) to (lO) above, wherein the ion concentration in the test liquid is measured in order to measure the specific gravity or osmotic pressure of the test liquid.

<Function> According to the present invention having such a configuration, when the ion exchanger to which a colored or coloring substance is ionically bonded is brought into contact with the test liquid, the electrolyte present in the test liquid and the colored or colored substance are brought into contact with each other. Ion exchange occurs with the color substance. As a result, an amount of colored or colored substance corresponding to the amount of electrolyte present in the test solution is released from the ion exchanger, so this separated colored or colored substance is detected and its coloring intensity is measured. By doing so, the amount of electrolyte, that is, the ion concentration, in the test liquid can be determined.

In this case, the colored or coloring substance has excellent solubility or dispersibility in the liquid such as the test liquid, or has little change in solubility depending on the ion concentration in the liquid (in particular, the solubility is almost constant). ), regardless of the ion concentration in the test solution or the solution containing it, almost all of the colored or colored substances released from the ion exchanger will be absorbed without floating or precipitation. By dissolving or dispersing the ion in a liquid and measuring the color intensity of the liquid, the ion concentration in the test liquid can be determined accurately.

In addition, the specific gravity and osmotic pressure of a test fluid, such as urine, are correlated with the ion concentration (amount of solute) in the test fluid, so these values can be calculated from the ion concentration in the test fluid measured as described above. can be found.

<Structure of the Invention> The ion concentration measuring method of the present invention will be described in detail below.

Examples of the ion exchanger used in the present invention include organic ion exchangers such as ion exchange resins and carbonaceous ion exchangers, and inorganic ion exchangers such as zeolite and montmorillonite. Preferably, a resin is used.

Examples of ion exchange resins used in the present invention include:
Examples include:

■Product name: Baker bond ABX (manufactured by Yamazen ■) ■Product name: Q A E -5ephadexA -
25 (manufactured by Pharmacia) ■Product name: Amberlight IRA-400 (manufactured by Organo■) ■Product name: Amberlight IRA-94 (manufactured by Organo■
■Product name: Amberlight CG400 (manufactured by Organo■) ■Product name: Amberlight IR-120 (Organo■
(manufactured by) ■Product name: Amberlight IRC-50 (Organo ■
(manufactured by) ■Product name: Amberlite IRA-200C (manufactured by Organo ■) ■Product name: Diaion 5K102 (manufactured by Mitsubishi Kasei ■) The above ■ to ■ are anion exchange resins, and the above ■ to ■ are cation exchange resins. be.

The material of the ion exchange resin is not particularly limited, and may include styrene,
Examples include acrylic, cellulose, and silica types.

Ion exchangers, typified by such ion exchange resins, may have an anion exchange group, a cation exchange group, or both (amphoteric ion exchangers). The ion exchanger may have either a functional group or a polyfunctional group.
04''-, PO,'', CO,-1) and/or cations (e.g., Na'', K'', NH4'', C
a'''', Mg2''').

Examples of the anion exchange group include amines such as a dimethylamino group, a trimethylammonium group, and a β-hydroxyethyldimethylammonium group.

Examples of cation exchange groups include sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups, arsenic acid groups, and selenic acid groups.

Examples of the form of the ion exchanger include particulate (powder, beads), scale, fiber, crushed material, etc. Among these, particulate and crushed materials are particularly preferred.

When the ion exchanger is particulate, the average particle size is 5 to 2
It is preferable to set it to about 00 units, particularly about 20 to 100 μs.

A colored or coloring substance is ionically bonded to the ion exchange group of such an ion exchanger.

Here, the term "coloring or coloring substance" includes pigments that have already been colored, pigments that have not yet developed color, and substances that do not develop color by themselves but develop or develop color by reacting with a predetermined substance (hereinafter referred to as "coloring substance"), etc. It is a concept.

This colored or color-forming substance is a solvent or dispersion medium (especially
Those with excellent solubility or dispersibility in water), that is, those with a relatively large absolute amount of coloring or color-forming substances dissolved or dispersed in the solvent or dispersion medium (e.g.
The amount dissolved at the ion concentration in standard urine is 5 g/cN.
above) is preferred.

Additionally, the solubility of a colored or color-forming substance generally tends to decrease as the ion concentration in the solution increases, but the absolute amount of dissolved color or color-forming substance is relatively small. Even if the ion concentration in the solution changes, the solubility has excellent stability (solubility decrease rate 0 to 4
(approximately 0%), and in particular, it is preferable that the solubility be substantially constant.

As a result, regardless of the ion concentration in the solution containing the test liquid, the colored or colored substance released from the ion exchanger will not float or precipitate (almost all of it will be dissolved in the solution, The ion concentration in the test liquid can be determined by measuring the color intensity.

Many of these water-soluble colored or colored substances have water-soluble groups such as sulfonic acid groups, hydroxyl groups, carboxylic acid groups, and amino groups. There are things that can be mentioned.

Acidic dyes having one or more anionic groups such as sulfo groups, carboxy groups, etc. in the molecule as anionic groups are preferable as those bonded to the anion exchange groups of the ion exchanger, such as tartrazine ( Color Ind
ex No. 19140), Acid Blue 92 (C
Color Index No. 13390), Acid Red 97 (Color Index No. 228)
90), Acid Red 1 (Color Index
No, 18050), Alizariero GG (Co
lor Index No. 14025), acid blue 45 (Co1or Index No. 14025), etc.
No. 63010), acid blue 129 (
Color Index No, 62058), Reactive Blue 3 G (Color Index N
o, 61211), 7side blue 25 (Col
or Index No., 62055), Acid Blue 40 (Color Index No., 62125)
), among which are tartrazine, acid blue 92, and acid blue 4.
5, Acid Blue 129 is preferred, and Tartrazine is particularly preferred.

In addition, basic dyes, such as Basic Red 29, can be bonded to the cation exchange group of the ion exchanger.
(Color Index No. 11460), Basic Blue 3 (Cofor I
ndex No. 51004) and other oxazine dyes,
Thiazine dyes such as methylene blue, and basic fuchsin (Color Index No.

425101, Crystal Violet (Color
Examples include triphenylmethane dyes such as Index No. 42555), and among these, Basic Red 29, Basic Blue 3, methylene blue, and Basic Tsuksin are particularly preferred.

Furthermore, when a water-soluble dye precursor is used as a coloring or color-forming substance, since it does not produce color by itself, it is necessary to add a color developer to develop color before detection.
Examples of such dye precursors include (1) phenol, resorcinol, pyrocatechol,
Hydroquinone, salicylic acid, m-.

Phenolic compounds such as p-hydroxysalicylic acid, o-, p-chlorophenol, o, p-bromophenol, phloroglycitur, and (2) aniline, N, N-dimethylaniline, N, N-diethylaniline, N-sulfonate. Propylaniline, N-methyl-N-sulfoprolyaniline, N-ethyl-N-sulfopropyltoluidine, N-
Methyl-N-sulfopropylaniline, N-ethyl-N
-Aniline compounds such as sulfopropylhydroxyaniline, etc.

In addition, as a color developer, (A) an oxidative condensation color-forming compound such as 4-aminoantipyrine or 3-methyl-2-benzothiazolinone (an oxidizing agent such as potassium ferricyanide is required during the color reaction); ) (B) Fast Red B Salt, Fast Red A
There are diazo coupling compounds such as L salt, Fast Red ITR salt, Fast Red Violet LB salt, Fast Violet B salt, Fast Blue B salt, Fast Blue BB salt, Fast Blue RR salt, and the like.

In this case, any of the color developers (A) and (B) can be used for the dye precursors (1) and (2).

In the present invention, an ion exchanger to which such a colored or color-forming substance is ionically bonded is used, and the ion concentration is measured, for example, in the following manner.

First, a colored or coloring substance is ionically bonded to the ion exchanger by a predetermined method. This method is carried out, for example, by mixing and stirring the ion exchanger and a liquid containing a colored or coloring substance, followed by washing and drying.

Next, the ion exchanger (hereinafter simply referred to as ion exchanger) to which the colored or coloring substance is ionically bonded is placed in a container such as a test tube or a petri dish. In this case, the amount of ion exchanger used is sufficient for ion exchange of the electrolyte in the test solution with the colored or color-forming substance bound thereto.

Note that a liquid substantially free of electrolyte, such as distilled water or ion-exchanged water, may be placed in the container in advance. Even if an ion exchanger is placed in such a liquid, the coloring or coloring substance remains ionically bound to the ion exchanger, so the coloring or coloring substance separates and enters the liquid in the container. Will not dissolve or disperse.

Next, a test liquid such as urine is put into the container.

This allows electrolytes in the test solution, such as Na',
K"", Mg24, NH4", Ca", C1-1so
42-, po4"-, Con-, etc. are ion-exchanged with the colored or color-forming substance. By this ion exchange, the colored or color-forming substance released from the ion exchanger is dissolved or dispersed in the water in the container.

When the coloring or coloring substance is a colored pigment, the liquid in the container becomes colored. Furthermore, when the coloring or color-forming substance is a pigment or a coloring substance before coloring, the liquid in the container changes color by adding a predetermined chemical and causing the color to develop.

The amount of colored or colored substance dissolved or dispersed in a liquid is
Since it is approximately proportional to the amount of electrolyte present in the test solution, it is possible to measure the amount of electrolyte, or ion concentration, in the test solution by measuring the coloring intensity of the solution in the container. can.

Note that the color intensity of the liquid in the container may be measured using a colorimetric method based on observation with the naked eye, but in order to obtain more accurate measurement results, an analyzer such as an absorption photometer may be used. It is preferable to measure optically.

The specific gravity and osmolality of a test fluid, particularly urine, can be determined by measuring the ion concentration in urine. In other words, the specific gravity and osmolarity of urine are correlated with the amount of solutes in the urine, but electrolytes in this solute have a roughly constant ratio (5
0 to 70%), therefore, the specific gravity and osmotic pressure of urine can be determined from the ion concentration in urine measured as described above.

In addition, in the present invention, when a non-electrolyte is present in the test solution, the non-electrolyte is decomposed to obtain an electrolyte, and this electrolyte and
It is also possible to measure the total amount of electrolyte including the electrolyte originally present in the test liquid.

For example, most of the non-electrolyte solutes in urine are urea, but this urea is decomposed into ammonia and carbon dioxide by urease, and this ammonium ion and
The originally existing sodium ions, potassium ions,
Measure the total amount of magnesium ions, calcium ions, etc. This makes it possible to determine the specific gravity and osmotic pressure of urine more accurately than by measuring only the amount of electrolyte originally present in urine.

Note that the test fluid in the present invention is not limited to urine, and may be body fluids such as blood, plasma, serum, lymph, spinal fluid, or other fluids.

<Example> Hereinafter, a specific example of the ion concentration measuring method of the present invention will be described.

(Example 1) Powdered strongly basic anion exchange resin with an average particle size of 80-
Manufactured by Pharmacia Product name: QAE-3ephadexA
-25), add 0.2% tartrazine aqueous solution,
After thorough stirring, the mixture was washed with water and dried under reduced pressure to obtain an ion exchange resin powder to which tartrazine was ionically bonded.

Prepare aqueous sodium chloride solutions with known concentrations of sodium chloride (1, 2.3, and 5 wt%, respectively) as test solutions for obtaining a calibration curve, and set the sodium ion concentrations and specific gravity of these solutions as follows. It was measured using

Add 0.1 g of the ion exchange resin powder to 5 ml of the test solution, stir thoroughly, then collect a portion of the supernatant, dilute it to an appropriate ratio, and measure the absorbance at a wavelength of 420 na+ (reflected absorbance). was measured. The absorbance was measured using a spectrophotometer U-2000 manufactured by Hitachi, Ltd.

The relationship between the sodium chloride concentration and specific gravity of the test solution and the absorbance (logarithmically converted value) is shown in the graph of FIG.

As shown in the figure, a calibration curve in which the absorbance changes depending on the ion concentration and specific gravity of the test solution was obtained.

Using the calibration curve thus obtained, the ion concentration and specific gravity (or osmotic pressure) of urine, which is a test liquid with unknown ion concentration, were determined.

Eight types of urine samples were collected, and their color and absorbance were measured in the same manner as above, and the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using the calibration curve shown in Figure 1. .

The specific gravity of each urine sample determined by this method is measured using a urine refractometer (
When comparing the specific gravity of each urine sample obtained by measurement using Uribet IID (manufactured by Wako Tsumugi Pharmaceutical Co., Ltd.), the error was within 5%, indicating that very highly accurate measurements were possible.

(Example 2) The same procedure as in Example 1 was carried out, except that 5 g of a powdered strongly basic anion exchange resin (Part name: Amberlite CG400 manufactured by Organo ■) with an average particle size of 80 μs was used as the ion exchange resin. When the ion concentration and specific gravity of the test solution were measured, a calibration curve shown in the graph of FIG. 1 was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate measurement results (error within 5%) were obtained.

(Example 3) The same procedure as in Example 1 was carried out, except that 5 g of a powdered basic anion exchange resin (manufactured by Organo ■, part name: Amberlite IRA-94) with an average particle size of 80 mm was used as the ion exchange resin. When the ion concentration and specific gravity of the test liquid were measured, the calibration curve shown in the graph of FIG. 1 was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate measurement results (error within 5%) were obtained.

(Example 4) In imparting color or a color-forming substance to the ion exchange resin, a 0.2% Acid Blue 92 aqueous solution was used instead of the tartrazine aqueous solution, but in the same manner as in Example 1,
When the ion concentration and specific gravity of the test liquid were measured, the second
A calibration curve shown in the graph of the figure was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate measurement results (error within 5%) were obtained.

(Example 5) In imparting color or a color-forming substance to the ion exchange resin, a 0°2% Acid Blue 45 dispersion was used instead of the tartrazine aqueous solution, but in the same manner as in Example 1.
When the ion concentration and specific gravity of the test liquid were measured, the second
A calibration curve shown in the graph of the figure was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate measurement results (error within 5%) were obtained.

(Example 6) The test solution was prepared in the same manner as in Example 1 except that 0.2% Acid Blue 129 aqueous solution was used in place of the tartrazine aqueous solution to impart color or a color-forming substance to the ion exchange resin. When the ion concentration and specific gravity were measured, a calibration curve shown in the graph of FIG. 2 was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate measurement results (error within 5%) were obtained.

(Example 7) As the ion exchange resin, 5 g of a powdered acidic cation exchange resin (Part name: Amberlite IR-120 manufactured by Organo ■) with an average particle size of 8 o- was used, and this ion exchange resin was colored or 0.2% when adding a coloring substance
The ion concentration and specific gravity of the test solution were measured in the same manner as in Example 1 except that the Basic Blue 3 aqueous solution was used, and the calibration curve shown in the graph of FIG. 3 was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate measurement results (error within 5%) were obtained.

(Example 8) As the ion exchange resin, 5 g of a powdered acidic cation exchange resin with an average particle size of 80 mm (Part name: Amberlite IRC-50 manufactured by Organo ■) was used, and this ion exchange resin was colored or 0.2% when adding a coloring substance
The ion concentration and specific gravity of the test solution were measured in the same manner as in Example 1 except that the Basic Red 29 aqueous solution was used, and the calibration curve shown in the graph of FIG. 3 was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate measurement results (error within 5%) were obtained.

(Example 9) Add 500 u of urease to 5 mN of urea aqueous solution (5 and 10 wt%) to decompose urea into ammonia and carbon dioxide, and use the dye adsorption resin of Example 7 to determine the ion concentration and specific gravity of the test solution. When measured, a calibration curve shown in the graph of FIG. 4 was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate measurement results (error within 2%) were obtained.

(Example 10) In the same sodium chloride aqueous solution as in Example 1, measurements were performed in a system using a coloring substance made of a dye precursor and a color developer.

5 g of powdered acidic cation exchange resin with an average particle size of 80 mm (Part name: Amberlite IR-120 manufactured by Organo ■)
In order to color or impart a coloring substance to this ion exchange resin, add 0.2% N,N-dimethylaniline aqueous solution, stir thoroughly, wash with water, dry under reduced pressure, and add N-N-dimethylaniline to the ion exchange resin. An ion exchange resin powder to which aniline was ionically bonded was obtained.

The measurement method is to add 0.1 g of the above N,N-dimethylaniline adsorption resin to 5 mg of the test liquid, stir for 1 minute, and then add 10 uj of 0.5% Fast Blue B salt aqueous solution to the supernatant liquid.
was added and stirred, and the absorbance at a wavelength of 467 nm was measured, and a calibration curve shown in the graph of Figure 5 was obtained.

When the ion concentration and specific gravity (or osmotic pressure) of each urine sample were determined using this calibration curve, highly accurate results (error within 5%) were obtained.

<Effects of the Invention> According to the present invention, the ion concentration in a test liquid can be measured quickly and accurately with simple operations without requiring expensive equipment or equipment unlike conventional methods. As a result, it is possible to improve the operability and measurement accuracy when measuring the ion concentration, specific gravity, or osmotic pressure of urine, contributing to the diagnosis of various diseases in clinical tests.

[Brief explanation of drawings]

FIG. 1, FIG. 2, FIG. 3, and FIG. 5 are graphs showing the relationship between the sodium chloride concentration and specific gravity of the test liquid, and the absorbance, respectively. FIG. 4 is a graph showing the relationship between the urea concentration and specific gravity of the test liquid and the absorbance. Patent applicant Terumo Co., Ltd. representative
Person Patent Attorney Yo Ishii - Same
Patent Attorney Increase 1) Hired by Tatsuya Kei (420nm)
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Claims (11)

[Claims] (1) Bringing an ion exchanger to which a colored or color-forming substance is ionically bonded into contact with a test liquid to ion-exchange the electrolyte present in the test liquid with the coloring or color-forming substance; A method for measuring ion concentration, characterized in that the amount of electrolyte in the test liquid is measured by detecting a colored or colored substance released from an ion exchanger. (2) The ion concentration measuring method according to claim 1, wherein the ion exchanger is an ion exchange resin. (3) The ion concentration measuring method according to claim 1 or 2, wherein the ion exchanger is in the form of particles. (4) The method for measuring ion concentration according to any one of claims 1 to 3, wherein the colored or coloring substance has excellent solubility or dispersibility. (5) The colored or color-forming substance has excellent solubility stability with respect to ion concentration in the solution.
3. The ion concentration measuring method according to any one of 3. (6) Any one of claims 1 to 5, wherein the coloring or coloring substance is at least one selected from the group consisting of azo dyes, anthraquinone dyes, triphenylmethane dyes, oxazine dyes, and thiazine dyes. The ion concentration measurement method described in . (7) The colored or color-forming substance includes tartrazine, acid blue 92, acid blue 45, acid blue 129, basic blue 3, basic red 29,
The method for measuring ion concentration according to any one of claims 1 to 6, wherein the ion concentration is at least one selected from the group consisting of basic fuchsin and methylene blue. (8) The ion concentration measuring method according to any one of claims 1 to 7, wherein the colored or colored substance is detected optically. (9) Any one of claims 1 to 8, wherein an electrolyte is obtained by decomposing a non-electrolyte present in the test liquid, and the total electrolyte amount of this electrolyte and the electrolyte originally present in the test liquid is measured. The ion concentration measurement method described. (10) The ion concentration measuring method according to any one of claims 1 to 9, wherein the test liquid is urine. (11) The ion concentration measuring method according to any one of claims 1 to 10, wherein the ion concentration in the test liquid is measured in order to measure the specific gravity or osmotic pressure of the test liquid.