JP2984524B2 - Cation measurement tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring instrument for determining the concentration of ions, particularly cations, in a solution.

[0002]

2. Description of the Related Art In the field of clinical examination, it is known that measurement of the ion concentration in serum or urine can provide useful information on the condition of a patient. Various methods such as a flame photometric method, an ion-selective electrode method, and a colorimetric method have been used for measuring such an ion concentration. Of these,
In the colorimetric method, the concentration of an ion is measured as an absorbance or a fluorescence intensity at a specific wavelength by using various coloring reagents. Since the colorimetric method has a feature that the structure of the measuring device is simplified, disposable measuring tools have also been developed.

[0003] As an ion concentration measuring instrument by colorimetry,
Measuring instrument for supporting an organic liquid layer containing a dye that shows a detectable response by interacting with the ionophore and complex formation between the ion and the ionophore on a porous carrier matrix and measuring the ion concentration in the liquid as absorbance or fluorescence intensity Is already known. For example, JP-A-60-194360
Japanese Patent Application Laid-Open Publication No. H10-157, pp describes an ion concentration measuring instrument in which an organic liquid layer containing various ionophores and a pH-sensitive dye called a reporter substance is supported on a porous carrier. When these measuring instruments are brought into contact with a sample aqueous solution containing a specific ion, the absorption spectrum or the fluorescence spectrum of the pH-sensitive dye changes depending on the ion concentration.

However, research by Simon et al. [ANALYTICAL SCIENCE 1990
Pp. 715-720] indicates that the above-mentioned measuring instrument develops a color sensitively to a change in pH in addition to the ion to be measured. Therefore, it is necessary for these ion concentration test devices to perform strict pH buffering. Also, substances known to be usable as reporter substances are p
Only the H-sensitive dye was present. Further, crown ether is generally used as the ionophore. Among crown ethers, those showing very good selectivity, particularly for alkali metals, are known, while those which form a complex selectively for other ions, that is, zinc ions and iron ions, are hardly found. unknown. Therefore, it is not suitable for measuring those ions.

[0005] The concentration of heavy metals in water has been measured by a colorimetric method. For example, as exemplified by phenanthroline, a substance that forms a color when it forms a complex with a specific metal ion is mixed in a measurement sample, and the absorbance at a specific wavelength is measured. An ion concentration test device using this principle is described in "Analytical Chemistry", Vol. 40 (1991), pp. 227-231. In this method, a film is used in which bathocuproine, which forms a complex specifically with monovalent copper ions and develops a color, is dissolved in a plasticizer, and this film is contacted with an aqueous solution containing an unknown concentration of monovalent copper ions. Measurement.
The copper ions and chloride ions co-extracted into the film from the aqueous solution further diffuse into the film, and the copper ions form a complex with bathocuproin to develop color. However, the color development response has a disadvantage that the time required for measurement is long because diffusion of ions in the film is rate-determining.
It is reported to take several hours.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to develop a cation measuring device which has a small influence of pH and can quickly and easily measure various cation concentrations in a liquid by a colorimetric method.

[0007]

Means for Solving the Problems The present inventors have intensively studied to develop a cation measuring device in a liquid which can solve such problems. As a result, by combining an ionophore with a dye capable of forming a complex with a cation such as a heavy metal ion or a metal ion, the concentration of an unknown cation in a liquid can be measured by a colorimetric method to achieve the intended purpose. Based on the knowledge, the present invention has been completed and provided.

That is, the present invention provides a complex comprising a predetermined ionophore and a cation and a dye whose light absorption spectrum can be changed by forming a complex with another cation different from the cation in a poorly water-soluble and slightly volatile organic solvent. It is a cation measuring device characterized by being contained.

Another object of the present invention is to provide a complex comprising a predetermined ionophore and a cation and a dye whose light absorption spectrum can be changed by forming a complex with another cation different from the cation in a poorly water-soluble and slightly volatile organic solvent. A cation measuring device characterized in that the contained organic solution is contained in a carrier matrix.

[0010] The present invention also provides a method for measuring a concentration of a cation having an unknown concentration capable of forming a complex with a predetermined ionophore and a constant concentration of a cation different from the cation capable of forming a complex with a dye, using the above-described cation measuring device. To form a complex between the unknown concentration of cation and the ionophore and the complex of the constant concentration of the cation and the dye. This is a method for quantifying cations, which comprises determining the concentration of an unknown cation in a sample solution that correlates with the absorbance by measuring the absorbance of the light absorption spectrum.

Further, another aspect of the present invention is to provide a cation measuring instrument as described above, wherein a cation having a certain concentration capable of forming a complex with a predetermined ionophore and a cation having an unknown concentration different from the cation capable of forming a complex with a dye. To form a complex between the cation and the ionophore at the constant concentration and the complex with the dye at the unknown concentration, and then form an amount of the complex between the cation and the dye at the unknown concentration. This is a method for quantifying cations, which comprises determining the concentration of an unknown cation in a sample solution correlated with the absorbance by measuring the absorbance of a light absorption spectrum caused by the cation.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An ionophore is an uncharged compound having a property of forming a complex with a specific cation. As the ionophore of the present invention, known compounds such as a cyclic peptide compound, a cyclic or acyclic polyether derivative, a potand derivative, and a calixarene derivative can be used without limitation.

Specific examples of ionophores which can be suitably used include lithium ionophore; 6,6-dibenzyl-1,4,8,11-tetraoxacyclotetradecane, 2,9-dibutyl-1,10-phenanthroline. Sodium ionophore; 5, 11, 17, 2
Potassium ionophore such as 3-tetra-t-butyl-25,26,27,28-tetrakis (ethoxycarbonyl) -methoxy-calix [4] arene, bis [(12-crown-4) methyl] methyldodecylmalonate; Valinomycin, 2,3-naphth-1,4,7,1
0,13-pentaoxacyclopentadec-2-ene,
Calcium ionophores such as bis [(benzo-15-crown-5) -4'-methyl] pimelate and valinomycin; diethyl N, N '-[(4R, 5R) -4,5
-Dimethyl-1,8-dioxo-3,6-dioxaoctamethylene] bis (12-methylaminododecanoate); magnesium ionophore; N, N'-diheptyl-N, N'-dimethylaspartamide , Copper ion ionophore; benzo-15-thiacrown-4-ether and the like.

There are other compounds known to form a complex with a cation, and they can be used. The literature on the ionophore is Yoshih
`` Cation Binding by Mac '' edited by isaInoue, George W. Gokel
rocycles "(MARCEL DEKKERINCORPORATION 1990),
Edited by Hiroyuki Takeda, "Application of Functional Macrocycles to Analytical Chemistry" (IPC, Inc., 1990), ANALYTICAL CHEMISTRY, Volume 20, 20
13-2016 page (1988).

As the cation of the present invention, any cation capable of forming a complex with the above ionophore can be selected. Specific examples include alkali metal ions such as sodium ion and potassium ion, and heavy metal ions such as copper ion and silver ion.

The complex comprising a given ionophore and a cation in the present invention can be easily formed by dissolving the ionophore and a salt of the cation in a poorly water-soluble and slightly volatile organic solvent.

The cation salt is a salt compound of the above-mentioned various cations. Specific examples thereof include potassium tetraphenylborate, silver tetrakis (4-fluorophenyl) borate, and tetrakis (4-chlorophenyl). Borate potassium salt, tetrakis [3,5-bis (trifluoromethyl) phenyl] sodium salt and the like can be mentioned.

In the present invention, a dye whose light absorption spectrum is changed by forming a complex with a cation (hereinafter, referred to as a dye)
Simply referred to as a dye) has the ability to form a complex with a cation such as a specific metal ion or heavy metal ion, and forming a complex with the cation causes a change in the electron orbital state of the cation, resulting in a change in the absorption spectrum of the complex. Refers to a dye that causes a change. Since the combinations of cations and dyes that cause changes in the light absorption spectrum are limited, such dyes are different from those conventionally used when measuring specific cations by colorimetry by liquid-liquid extraction. It is selected and, if necessary, chemically modified so that it can be dissolved in a hardly water-soluble hardly volatile organic solvent.

The dye used in the present invention must be soluble in a poorly water-soluble and slightly volatile organic solvent. When it is insoluble in the hardly water-soluble hardly volatile organic solvent, the absorption spectrum does not change. Although the change in the light absorption spectrum is generally called color development, the present invention is not necessarily limited to the case where the change in the light absorption spectrum occurs in the visible region that can be seen by the eye. Can also be applied when a change occurs.

Specific examples of preferably used dyes include bathocuproine, bathophenanthroline, 2- (5
-Bromo-2-pyridylazo) -5-diethylaminophenol, 2- (2-benzothiazoylazo) -5-dimethylaminobenzoic acid, 4- (2-pyridylazo) resorcinol and the like.

The cation capable of selectively forming a complex with the dye of the present invention and changing the light absorption spectrum is
A cation different from the cation that forms a complex with the ionophore described above must be used.

Examples of suitable cations forming a complex with the above-mentioned dyes include metal ions such as aluminum ion (III) and magnesium (II) ion; copper (I), copper (II) ion; Iron (II) ion, nickel (II) ion, zinc (II) ion, cobalt (II
There are heavy metal ions such as I) ions and cadmium (II) ions.

Examples of suitable combinations of the above cations and dyes include copper (I) ion and bathocuproine, iron (II) ion or copper (I) ion or ternium (II) ion and bathophenanthroline, copper ( II) ion or nickel (II) ion or cobalt (II) ion or zinc (II) ion
(5-bromo-2-pyridylazo) -5-diethylaminophenol, nickel (II) ion and 2- (2-benzothiazoylazo) -5-dimethylaminobenzoic acid.

The hardly water-soluble and hardly volatile organic solvent (hereinafter simply referred to as an organic solvent) of the present invention is an organic compound which is hardly soluble in water, has a high boiling point, does not have an ionizable functional group, and is liquid at room temperature. Is used. Specifically, the boiling point is 100 degrees Celsius
Or more, and the amount of an organic solvent that can be dissolved in water 11 is preferably about 1 g or less in order to obtain a stable response.

Examples of suitable organic solvents include high-boiling esters such as dibutyl adipate and dioctyl phthalate, and high-boiling ethers such as O-nitrophenyloctyl ether and diphenyl ether.

Most preferably, the molar ratio of the ionophore to the complexing cation is 1: 1 for maximum sensitivity. With a molar ratio other than this, a change response of the light absorption spectrum can be obtained, but the sensitivity is slightly inferior. Generally, the molar ratio that can be used is from 0.5: 1 to 2: 1 ionophore: cation.

The concentrations of the complex comprising the ionophore and the cation and the dye in the organic solvent cannot be unconditionally limited because their upper limits differ depending on the solubility of the compound used. The lower limit also varies depending on the absorbance required by the absorbance measurement device. A preferred range is 0.1 to 200 mM, and a particularly preferred range is 5 to 120 mM. When the concentration is low, the absorbance response or the fluorescence response becomes small and the measurement becomes difficult. On the other hand, if the concentration is too high, ionophores or dye crystals are precipitated, and the measurement is still difficult.

The optimum value of the molar ratio between the ionophore and the dye is as follows: the valence of the cation forming the complex and the valence of the cation, and the number of the ionophore coordinated to one cation.
And the number of dyes coordinated to one cation.
In the following equation, it has been found that the best sensitivity is obtained when the coefficient k is 1.

Ionophore: dye = valence of cation forming complex with dye x number of ionophore coordinating with cation: k x valence of cation forming complex with ionophore x number of dye coordinating cation Other molar ratios may be used. In the molar ratio between the ionophore and the dye suitably used in the present invention, the coefficient k is 0.2 to 5.

For example, potassium ion is used as a cation forming a complex with an ionophore, valinomycin forming a 1: 1 complex with a potassium ion is used as an ionophore, copper (I) ion is used as a cation forming a complex, and copper (I) is used as a dye. I) When bathocuproine which forms a 1: 2 complex with ions is used, the optimum value of the molar ratio between the ionophore and the dye can be obtained as follows.

Ionophore: Dye = 1 × 1: k × 1 × 2 When k is 1, ionophore: dye = 1: 2, and the maximum sensitivity is obtained at this time.

The method of incorporating the complex or dye comprising an ionophore and a cation into an organic solvent is not particularly limited, and various methods can be used.

For example, an organic solvent, an ionophore, a salt of a cation capable of forming a complex with the ionophore, and a dye are placed in a container such as a flask, and the mixture can be shaken to contain them. When the solubility of the complex or dye consisting of the ionophore and the cation in an organic solvent is small,
The organic solvent can be dissolved and contained by heating and stirring. It is necessary that at least a part of the complex and the dye composed of the ionophore and the cation is dissolved in an organic solvent. Particularly, when all of the complex and the dye composed of the ionophore and the cation are dissolved in the organic solvent, accurate and highly sensitive measurement can be performed.

The cation forming a complex with the ionophore of the present invention forms an ion pair with an anion in an organic solvent and exists as a salt. As the anion, an anion derived from the above-mentioned cation salt is usually used. The anion is preferably a hydrophobic anion, and specific examples thereof include a tetraphenylborate ion, a tetrakis (4-chlorophenyl) borate ion, and a tetrakis [3,5-bis (trifluoromethyl) phenyl] ion.

Further, when the dye whose light absorption spectrum changes by forming a complex with the cation of the present invention has an anionic group such as sulfonic acid, the dye is used as a source of the hydrophobic anion. Can also be used.

The organic solution of the present invention contains a complex composed of an ionophore and a cation, a dye whose light absorption spectrum is changed by forming a complex with the cation, and an organic solvent. Additives are added to improve the physical properties of the.

As additives, for example, polyvinyl chloride,
By adding a polymer such as polymethyl methacrylate, the fluidity of the organic solvent can be reduced and the physical strength can be improved. As these additives, those that dissolve in an organic solvent can be used, and they can be used at or below the upper limit of the solubility.

As the carrier matrix of the present invention, those having porosity and not soluble in an organic solvent are used.
Specific examples that can be suitably used include a glass filter, a glass fiber filter, a membrane filter, and paper.

The carrier matrix used in the present invention needs to have an opening through which an aqueous sample solution can penetrate even after the organic solution is contained. For this reason, the amount of the organic solution to be included depends on the porosity of the porous carrier and cannot be limited, but is generally 0.1 to the weight of the porous carrier.
~ 2 times the weight of the organic solution is impregnated.

A known method can be used for incorporating the organic solution of the present invention into a carrier matrix. Typically, a method in which an organic solution is once dissolved in a solvent capable of dissolving the solution, then the solution is impregnated into a carrier matrix, and then dried (hereinafter referred to as a cast method) is suitably used.

The embodiment in which the organic solvent containing a complex of the present invention comprising a ionophore and a cation and a dye whose light absorption spectrum is changed by forming a complex with another cation different from the cation is used as a cation measuring device. Not limited. The typical method is as follows.

That is, an organic solvent containing a complex composed of an ionophore and a cation and a dye whose light absorption spectrum changes by forming a complex with another cation different from the cation is placed on a resin plate such as polyester or polypropylene. This is a method of forming a film having a thickness of several microns to several hundred microns by coating.

An organic solution containing an ionophore of the present invention and a cation, and a dye whose light absorption spectrum is changed by forming a complex with another cation different from the cation in an organic solvent is contained in a carrier matrix. The embodiment of the included cation measuring device is not particularly limited. A typical example is as follows.

That is, first, an organic solution containing a complex comprising an ionophore and a cation and a dye whose light absorption spectrum is changed by forming a complex with another cation different from the cation is used. Prepare a solution diluted with a possible organic solvent. Next, the solution is impregnated into the carrier matrix, and thereafter, the organic solvent is volatilized, whereby the solution is included in the carrier matrix as an organic liquid layer. The cation measuring device is formed by bonding the obtained carrier matrix to a resin plate such as polyester or polypropylene with a double-sided tape.

Various methods can be used for preliminarily including a cation forming a complex with the dye of the present invention or another cation different from the cation in the sample solution at a constant concentration. The method described is preferably used. That is, a method of preliminarily containing a constant concentration of cations in a sample solution can be performed by adding a constant amount and a known concentration of an aqueous cation solution to a fixed amount of a sample solution and stirring the solution. At this time, the concentration of the cation in the sample solution is represented by the following equation.

Concentration = (additional concentration) / (sample volume + additional volume) Of course, in order to know the concentration after addition by the above formula, the same cation must not be present in the sample. Therefore, as the predetermined cation, a cation that is known not to be present in the sample must be selected.

When an unknown concentration of cation in a sample solution is measured using the cation measuring device of the present invention, a cation which forms a complex with the unknown concentration of cation and an ionophore previously contained in the organic solution of the cation measuring device. Is
The same kind of cation or different kinds of cations may be used. However, when the cations are different cations, the formation constant for forming a complex of the ionophore and the cation contained in the sample solution is a complex of the ionophore and the cation previously contained in the organic solution of the cation measuring device. Needs to be larger than the formation constant that forms

The reason for this will be described later as the mechanism of the change in absorbance in the cation measuring device of the present invention. However, when the above-defined production constant is small, it is contained in a sample solution capable of forming a complex with a predetermined ionophore. The cation to be measured is not incorporated into the organic solution of the cation measuring instrument, and only the cation that forms a complex with the dye is unilaterally incorporated into the organic solution. This is because no change occurs.

In the present invention, an example of a suitable combination of a cation in the organic solution and a cation in the sample solution which forms a complex with a given ionophore contained in the organic solution of the cation measuring device is given. For example, when using bis [(benzo-15-crown-5) -4'-hydroxymethyl] pimelate which is a potassium ionophore, potassium ion is used as the same kind of cation, and sodium ion or lithium ion is used as the different cation. Alternatively, potassium ions can be used.

When the cation forming a complex with the ionophore and the cation of the sample solution are the same cation in the cation measuring device of the present invention, the light absorption spectrum changes as follows. That is, when the sample solution is brought into contact with the cation measuring device, other cations in the sample solution that are different from the cation of the sample solution that is also the same species as the cation forming the complex with the ionophore are complexed with the dye of the cation measuring device. By being formed, it is taken into the organic solution and the light absorption spectrum changes. At the same time, in the organic solution of the cation measuring device, in order to maintain electrical neutrality,
Cations complexed with the ionophore are released into the sample solution. Here, an equilibrium is established between the concentrations of the cations in the sample solution, which are the same species as the cations forming the complex with the ionophore, which are present in the organic solution and the sample solution of the cation measuring device. Therefore, the release of the cation forming a complex with the ionophore from the organic solution is suppressed by the same kind of cation present in the sample solution. The degree of this suppression depends on the concentration of the same type of cation in the sample solution, and the higher the concentration of cation in the sample solution, the greater the degree of suppression. Unless the cation is released from the organic solution of the cation measuring device, the cation that forms a complex with the dye is not incorporated into the organic solution.As a result, the amount of the cation incorporated into the organic solution is the same as that of the ionophore in the sample solution. It depends on the concentration of the same kind of cation as the complex forming cation. That is, when the concentration of the same kind of cation as the cation forming a complex with the ionophore in the sample solution is high, the absorbance of the dye of the cation measuring instrument is small, and conversely, the cation forming a complex with the ionophore in the sample solution. When the concentration of the same type of cation is low, the absorbance of the dye of the cation measuring device increases.

In the present invention, when the cation which forms a complex with the ionophore with the cation measuring device and the cation of the sample solution are different cations, the light absorption spectrum changes as follows. . That is, when the sample solution is brought into contact with the cation measuring device, the cation in the sample solution capable of forming a complex with the dye of the cation measuring device is taken into the organic solution by forming a complex with the dye, and the light absorption spectrum changes. . At the same time, cations forming a complex with the ionophore are released into the sample solution in order to keep the cation measuring device electrically neutral in the organic solution. Further, cations forming a complex in the organic solution of the cation measuring device and cations present in the sample solution capable of forming a complex with the ionophore can be ion-exchanged, and cations capable of forming a complex with the ionophore are: Cations that are incorporated into the organic solution and simultaneously form a complex with the ionophore to maintain electrical neutrality are released into the sample solution. The process of transfer of these two cations occurs competitively. The total charge of the cation that can be taken into the organic solution of the cation measuring device is equal to the total charge of the cation that has previously formed a complex with the ionophore in the organic solution. The total amount of each cation that can be taken into the organic solution of the cation measuring device from the sample solution is determined by this total charge. The amount ratio of each cation taken into the organic solution of the cation measuring device from the sample solution is determined by the concentration of each cation in the sample solution and the formation constant at which the cation forms a complex with the ionophore or the dye. Since the generation constant is constant between each measurement, the ratio of the amount of each cation taken into the organic solution of the cation measuring device from the sample solution is determined by the concentration of each cation in the sample solution. That is, if the concentration of the cation capable of forming a complex with the dye in the sample solution is higher than the concentration of the cation capable of forming a complex with the ionophore in the sample solution, the cation capable of forming a complex with the dye is the organic solution of the cation measuring device. The amount taken in increases and the change in absorbance of the dye increases. Conversely, if the concentration of cations in the sample solution that can form a complex with the ionophore is high, the amount of cations that can form a complex with the dye will be incorporated into the organic solution of the cation measuring device, and the change in absorbance of the dye will be small. Become.

However, the formation constant of the complex of the cation and the ionophore which has previously formed a complex in the organic solution of the cation measuring instrument is the formation constant of the complex of the cation and the ionophore present in the sample solution which can form the complex with the ionophore. Only when it is smaller, the two cations can undergo ion exchange, and the cation in the sample solution that can form a complex with the ionophore is incorporated into the organic solution, and at the same time, the ionophore is used to maintain electrical neutrality. Cations in the organic solution which form a complex with the cation are released into the sample solution. When this condition is not satisfied, the cation capable of forming a complex with the dye in the sample solution is unilaterally incorporated into the organic solution, and no change in the absorbance of the dye depending on the ion concentration is obtained.

For the above reason, the cation which forms a complex with the ionophore in the organic solution of the cation measuring device in advance,
Regardless of whether the cations in the sample solution capable of forming a complex with the ionophore are the same or different, a change in the absorbance of the dye reflecting the ratio of the concentrations of these two cations in the sample solution is obtained. Here, if any one of the cations is constant between each measurement, in the present invention, the dye of the cation measuring device gives a change in absorbance according to the concentration of the other cation, and the change in the light absorption spectrum of the cation measuring device. Get up.

The cation measuring device of the present invention is brought into contact with the sample solution by, for example, immersing the sample solution in the sample solution or dropping the sample solution on the cation measuring device in a small amount. As a result, a change in the light absorption spectrum occurs in the measurement tool. This spectrum change can be quantified by measuring a reflected light absorption spectrum, a transmitted light absorption spectrum, and the like. As a specific measuring method, for example, using the cation measuring device of the present invention, a plurality of sample solutions of known concentrations of cations to be measured are prepared, and each light absorption spectrum is measured, and the cation concentration is determined in advance. A calibration curve between the absorbances at the wavelengths is prepared. Thereafter, by measuring the absorbance of the unknown concentration sample solution, the cation concentration in the unknown concentration sample solution can be known from the absorbance.

[0055]

The mechanism for changing the light absorption spectrum of the cation measuring device of the present invention is as described above.

The cation measuring device of the present invention uses an organic solution containing a complex consisting of a predetermined ionophore and a cation and a dye whose light absorption spectrum changes by forming a complex with another cation different from the cation. In addition, the concentration of the specific cation in the sample solution can be determined.

Since an ionophore and a dye which selectively form a complex with a specific cation are used, the measurement can be performed with less interference of other ions in the sample solution, and the measurement can be performed with less error.

Further, since a dye whose light absorption spectrum is changed by forming a complex with a specific cation is used,
Less affected by pH.

Further, ion exchange between the organic solvent and the sample solution is performed to form a complex of the dye and the cation.
The light absorption spectrum changes faster than a conventional cation measuring instrument using only extraction, and measurement can be performed quickly.

In particular, since the cation measuring device of the present invention has a large response speed of the change in the light absorption spectrum, the change response of the light absorption spectrum of the measuring device is completed quickly, and the result of the measurement of the ion concentration can be obtained quickly. It can be known and provides a great benefit in the case of highly urgent measurement, that is, in the measurement of blood ion concentration in the field of emergency medicine or the operating room. In addition, the number of serum or urine samples measured within a limited period of time in a general clinical test is increased, thereby improving work efficiency and facilitating diagnosis.

Further, since the cation measuring device of the present invention is hardly affected by pH, it has an advantage that accurate results can be obtained even when measuring a sample solution having a sharp fluctuation in pH such as a urine sample. .

From the above points, the industrial value of the present invention is extremely large.

[0063]

EXAMPLES The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 5.2 mg of valinomycin as potassium ionophore
(4.6 μmol), 2.2 mg (4.2 μmo) of potassium tetrakis (4-chlorophenyl) borate as a salt of a cation which has previously formed a complex with the ionophore.
l) 2- (5-bromo-2-pyridylazo) -5-diethylaminophenol 0.7 mg as a dye that forms a complex with zinc (II) ion and changes the light absorption spectrum
(2.0 µmol), 80 mg of o-nitrophenyloctyl ether as an organic solvent, and 8.0 mg of polyvinyl chloride as an additive were dissolved in 2.0 ml of tetrahydrofuran. 45 μl of this solution was impregnated into 1.5 cm square filter paper (Toyo Roshi Kaisha, No. 7) and dried at room temperature to prepare a cation measuring device. This cation measuring instrument was attached to the reflection / absorption spectrometer shown in FIG. 1, 50 μl of an aqueous solution having a zinc chloride concentration of 1 mM and a potassium chloride concentration of 0.1 mM was dropped, and the change in reflection absorbance at a wavelength of 550 nm was measured. The results are shown in FIG. Immediately after the dropping, the time required until the response was completed was within 2 minutes.

Comparative Example 1 0.7 mg of 2- (5-bromo-2-pyridylazo) -5-dimethylaminophenol as a dye which forms a complex with zinc (II) ion and changes the light absorption spectrum.
0 μmol), 80 mg of o-nitrophenyloctyl ether as an organic solvent, and 8.0 mg of polyvinyl chloride as an additive were dissolved in 2.0 ml of tetrahydrofuran. 45 μl of this solution was impregnated into 1.5 cm square filter paper (Toyo Roshi Kaisha, No. 7) and dried at room temperature to prepare a cation measuring device. This cation measuring instrument was attached to the reflection absorption spectrum measuring apparatus shown in FIG.
1 was added dropwise, and the change in reflection absorbance at a wavelength of 550 nm was measured. The results are shown in FIG. 2 immediately after dropping
Absorbance continued to change over minutes, and the response did not end.

From Example 1 and Comparative Example 1, the organic solvent contained a complex comprising a given ionophore and a cation and a dye whose light absorption spectrum was changed by forming a complex with another cation different from the cation. In this case, it was found that a quick response response of the light absorption spectrum was obtained.

Example 2 As a sodium ionophore, 5,11,17,23-
2.3 mg (2.3 μmol) of tetra-t-butyl-25,26,27,28-tetrakis (ethoxycarbonyl) -methoxy-calix [4] arene, sodium as a salt of a cation previously complexed with an ionophore Tetrakis [3,5-bis (trifluoromethyl) phenyl] borate 2.0 mg (2.3 μmo
l) Bathocuproin 0.8 mg as a dye which forms a complex with copper (I) ion and changes the light absorption spectrum
(2.3 μmol), 80 mg of o-nitrophenyloctyl ether as an organic solvent, and 8.0 mg of polyvinyl chloride as an additive were dissolved in 2.0 ml of tetrahydrofuran. 45 μl of this solution was impregnated into 1.5 cm square filter paper (Toyo Roshi Kaisha No. 7), and then dried at room temperature.
A cation measuring device was prepared. Fig. 1
And 50 μl of an aqueous solution containing various concentrations of copper (I) ions and 0.1 mM potassium chloride was dropped, and the wavelength at that time was 480 nm.
Was measured for reflection absorbance. An aqueous solution of copper (I) ions was prepared according to Analytical Chemistry, Vol. 40 (1991), pp. 227-231. FIG. 4 shows the relationship between the absorbance and the copper chloride concentration.

In the concentration range of 0.1 mM to 10 mM, there is a positive correlation between the absorbance and the copper (I) ion concentration, and there is no need to particularly perform pH buffering. It was found that copper ions could be quantified.

Example 3 As a potassium ionophore, 3.4 mg (4.6 μmol) of bis [(benzo-15-crown-5) -4'-hydroxymethyl] pimelate was prepared as a salt of a cation previously complexed with the ionophore. Sodium tetrakis [3,5-bis (trifluoromethyl) phenyl]
4.0 mg (4.6 μmol) of borate, cobalt (I
I) 0.9 mg of 2- (3,5-dibromo-2-pyridylazo) -5-diethylaminophenol (2.
1 μmol), 80 mg of o-nitrophenyloctyl ether as an organic solvent, and 8.0 mg of polyvinyl chloride as an additive were dissolved in 2.0 ml of tetrahydrofuran. 45 μl of this solution was impregnated into 1.5 cm square filter paper (Toyo Roshi Kaisha, No. 7) and dried at room temperature to prepare a cation measuring device. This cation measuring instrument was attached to the reflection and absorption spectrum measuring apparatus shown in FIG. 1, and 50 μl of an aqueous solution containing 1 mM of cobalt (II) chloride, potassium chloride or sodium chloride at various concentrations was dropped, and the wavelength at 590 nm was measured. The reflection absorbance was measured. FIG. 5 shows the relationship between the absorbance and the concentrations of potassium chloride and sodium chloride.

In the concentration range of about 1 mM to 100 mM, there was a positive correlation between the absorbance and the potassium ion concentration, and it was found that the potassium ion concentration could be quantified using the cation measuring device of the present invention. In addition, coloration does not occur for sodium ions unless the concentration is higher than that for potassium ions, indicating that the cation measuring device of the present invention selectively responds to specific ions for coloring.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a reflection absorbance spectrum measuring device used in Examples and Comparative Examples.

FIG. 2 is a diagram showing the relationship between the elapsed time immediately after the dropping of the aqueous solution measured in Example 1 and the measured absorbance.

FIG. 3 is a diagram showing the relationship between the time elapsed immediately after the dropping of the aqueous solution measured in Comparative Example 1 and the measured absorbance.

FIG. 4 is a diagram showing a relationship between a copper (I) ion concentration measured in Example 2 and a measured absorbance.

FIG. 5 is a diagram showing the relationship between the measured sodium ion concentration and potassium ion concentration and the measured absorbance in Example 3.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Xenon lamp 2 Condensing lens 3 Optical fiber for light projection 4 units (glass plate) 5 Cation measuring tool of the present invention 6 Optical fiber for light reception 7 Instantaneous multi-photometer (MCPD-1 manufactured by Otsuka Electronics Co., Ltd.)
000) 8 Data processor (Otsuka Electronics Co., Ltd.)

Claims (4)

(57) [Claims] 1. A poorly water-soluble, slightly volatile organic solvent containing a complex comprising a predetermined ionophore and a cation and a dye whose light absorption spectrum can be changed by forming a complex with another cation different from the cation. A cation measuring device, characterized in that: 2. An organic compound comprising a complex comprising a predetermined ionophore and a cation and a dye whose light absorption spectrum can be changed by the formation of a complex with another cation different from the cation in a poorly water-soluble and slightly volatile organic solvent. A cation measuring device characterized by comprising a solution in a carrier matrix. 3. The cation measuring device according to claim 1, wherein the cation has an unknown concentration capable of forming a complex with a predetermined ionophore and a certain concentration different from the cation capable of forming a complex with a dye. Contacting with a sample solution containing a cation to competitively form the complex of the unknown concentration of the cation and the ionophore and the complex of the constant concentration of the cation and the dye, and then form the complex of the constant concentration of the cation and the dye A method for quantifying cations, comprising determining the concentration of an unknown cation in a sample solution correlated with the absorbance by measuring the absorbance of a light absorption spectrum caused by the amount. 4. A cation measuring device according to claim 1 or 2, wherein the cation has a certain concentration capable of forming a complex with a predetermined ionophore and an unknown concentration different from the cation capable of forming a complex with a dye. Contact with a cation-containing sample solution to competitively form the constant concentration of the cation and ionophore and the unknown concentration of the cation and the dye, and then form the complex of the unknown concentration of the cation and the dye A method for quantifying cations, comprising determining the concentration of an unknown cation in a sample solution correlated with the absorbance by measuring the absorbance of a light absorption spectrum caused by the amount.