WO2013189265A1 - Method, system, and kit for detecting potassium ion concentration - Google Patents

Description

 Potassium ion concentration detection method, system and kit

Cross-reference to related applications

 This application claims priority to Chinese patent applications 201210206227.2 201210207722.5, 201210205843.6 and 201210205861.4 submitted on June 18, 2012. This application includes the entire contents of the above application by reference. Technical field

 The invention belongs to the field of biomedicine, and in particular relates to a method for detecting potassium ion concentration. BACKGROUND OF THE INVENTION Potassium in the human body is the main cation for maintaining physiological activity of cells, maintaining the normal osmotic pressure and acid-base balance of the body, participating in sugar and protein metabolism, and ensuring the normal function of nerve muscles, and its content is important for human physiological activities. index. The levels of potassium ions in urine and serum are clinically useful for diagnosing diseases such as kidneys and heart.

 Under normal circumstances, the body's potassium ion concentration has a reasonable reference range, such as: 3.5~5.5 mmol/L in serum; 25~125 mmol/24h in urine. When the potassium ion is higher than the reference value, it shows hyperkalemia. The main reasons are: acute renal failure, severe hemolysis or tissue damage, acute acidosis or tissue hypoxia, adrenal insufficiency, aldosterone deficiency, long-term application of diuretics , familial hyperkalemia and so on. High serum potassium levels can also cause severe stress, myocardial and respiratory dysfunction, as well as specific electrocardiographic changes. These symptoms occur when serum potassium is higher than 7mmol/L. When it exceeds 10mmol/L, ventricular fibrillation occurs and cardiac arrest leads to death. Conversely, when potassium intake is insufficient, potassium loss is severe, and kidney disease is transferred to the polyuria, symptoms of hypokalemia may occur.

 The methods for determining the concentration of potassium ions in the prior art are mainly: neutron activation method, isotope dilution mass spectrometry, chemical measurement method, flame photometry, ion selective electrode method, enzyme kinetic method, atomic spectrophotometry, and the like. Currently, methods commonly used clinically are flame photometry and ion selective electrode methods.

(1) Flame photometry: Flame photometry is an emission spectrometry method that uses the spectral intensity of the excited state atoms in the flame to return to the ground state for content analysis. It can detect serum, urine, cerebrospinal fluid and chest and ascites. Na+ and K+, this method belongs to the classic standard reference method. The advantage is that the result is accurate and reliable, and it is widely used clinically. The commonly used quantitative methods are the external standard method and the internal standard method. The external standard method generally has large operational errors and is not commonly used. The internal standard method is that the specimen and the standard solution are measured by adding the same internal standard element. Generally, the lithium internal standard is added, and the ratio of the lithium/potassium current is measured, instead of the current of the potassium alone, so that the gas can be reduced. And the error caused by factors such as flame temperature fluctuation, and thus has better accuracy.

 (2) Ion-selective electrode method (ISE method): Determination of potassium and sodium ions in serum and urine on a dedicated instrument. Because it has the advantages of low sample consumption, fast and accurate, and easy operation, it is the most convenient and accurate method among all the current methods, and there is almost a tendency to replace other methods. The principle is: The ion selective electrode is an electrochemical sensor with a sensitive membrane electrode that selectively responds to specific ions, converting the ion activity into a potential signal, within a certain range, its potential and solution. The logarithm of the specific ion activity is linear. The ion activity of the unknown solution can be obtained by comparison with the solution of the known ion concentration. According to the measurement process, it is divided into the direct measurement method and the indirect measurement method. The measurement method is performed by diluting the sample to be tested by an indirect measurement method, and the measured ion activity is closer to the ion concentration.

 At present, the main electrode types are: glass membrane electrode, inductive material is glass membrane; solid phase electrode, pressed by insoluble metal material; liquid membrane electrode, epoxy resin or built-in polyvinyl chloride as sensing membrane; Κ+ electrode made of plain film. These electrodes have a certain lifetime, after a period of time, the electrodes will age, and the price

(3) Chemical determination method: At present, the chemical determination of Κ+ mainly utilizes complex ring crown compounds such as acacia or spheroidal ether, also known as crown ether, which are all determined by ionophore, due to the presence of voids in the macrocyclic structure. Oxygen atoms in the molecule have unshared electron pairs that can be combined with metal ions. According to the size of the holes, metal ions of different diameters can be selectively combined, so that the ion concentration can be measured.

 (4) Enzymatic method: The principle of enzymatic determination of potassium is to use the activation of pyruvate kinase, which catalyzes the conversion of phosphoenolpyruvate to lactic acid accompanied by the consumption of reduced coenzyme I, and measures NADH at a wavelength of 340 nm. The absorbance drops.

 (5) Atomic spectrophotometry can also be used to detect potassium and sodium ions in serum, but the operation is complicated and the error is large, which is not as simple as flame photometry. Summary of the invention

OBJECTS OF THE INVENTION: To provide a novel method for detecting potassium ion concentration by using cyanine dye supramolecular and guanine quadruplex (G-quadruplex) action system, and potassium ion concentration detecting reagent prepared by using the method box. Quantitative analysis of potassium in serum or urine using UV absorption spectroscopy or fluorescence spectroscopy using reagents in the kit The concentration of ions, the measurement process is not affected by sodium ions or other trace elements, and the accuracy is high. At the same time, due to the high sensitivity of the reagent, the color change of the potassium ion concentration is visible to the naked eye, and visual detection can be realized.

 The general technical route of the present invention is to: regulate the formation or conformational transformation of the G-quadruplex structure by adding potassium ions, and then the cyanine dye recognizes the change of the G-quadruplex structure, thereby reflecting the concentration level of potassium ions. Specifically: In the absence of sodium ions and other metal cations, potassium ions promote the conversion of single-stranded DNA sequences into G-quadruplex structures. With the formation of G-quadruplex structures, the aggregation morphology of cyanine dyes occurs. Change, so that the color changes, to achieve macroscopic observation, and also significant changes in the ultraviolet absorption spectrum and fluorescence spectrum, the degree of change in absorbance and fluorescence intensity is proportional to the concentration of potassium ions, thereby achieving quantitative reflection of potassium ion levels; Or in the presence of sodium ions, the DNA sequence forms an anti-parallel structure G-quadruplex, and the addition of a potassium ion anti-parallel G-quadruplex undergoes a conformational transition. As the G-quadruplex conforms, the cyanine dye aggregates. The morphology changes, and the color change, the ultraviolet absorption spectrum and the fluorescence spectrum also change significantly. The degree of change in absorbance and fluorescence intensity is proportional to the potassium ion concentration, which can quantitatively reflect the potassium ion level.

 A first aspect of the invention provides a method of detecting a concentration of potassium ions in a liquid sample, the method comprising the steps of:

 (1) preparing a plurality of solution samples having different potassium ion concentrations using a buffer solution having a pH of 6.2 to 8.2, wherein each of the solution samples contains the same concentration of DNA molecules capable of forming a G-quadruplex and the same concentration of cyanine Dye

 (2) placing the plurality of solution samples under an ultraviolet visible light absorption spectrometer or a spectrophotometer, detecting an absorbance value at the first wavelength and an absorbance value at the second wavelength, or placing the plurality of solution samples in the fluorescence Under the spectrometer, the excitation intensity of the wavelength at the third wavelength is detected using an excitation wavelength of 560 nm, wherein the first wavelength is in the range of 560 nm to 590 nm, and the second wavelength is in the range of 500 nm to 540 nm, and the third wavelength is 580nm to 640nm range;

 (3) taking the potassium ion concentration of each of the solution samples as the abscissa or the ordinate, the absorbance value at the first wavelength or the absorbance value at the second wavelength measured in the step (2) or at the first wavelength Obtaining a ratio of the absorbance value to the absorbance value at the second wavelength or the fluorescence intensity at the third wavelength is plotted on the ordinate or the abscissa to obtain a standard curve of the potassium ion concentration;

 (4) adding a DNA molecule capable of forming a G-quadruplex, a compound of the formula I, and a buffer to the liquid sample to be tested, so that the concentration of the DNA molecule capable of forming the G-quadruplex in the liquid sample to be tested, The concentration of the compound of formula I and the pH value are identical to the solution sample in step (1), thereby obtaining a test solution;

(5) placing the test solution obtained in the step (4) under an ultraviolet visible light absorption spectrometer or a spectrophotometer, Detecting the absorbance value of the test solution at the first wavelength and the second wavelength, or placing the test solution under a fluorescence spectrometer, and detecting the fluorescence intensity value at the third wavelength by using an excitation wavelength of 560 nm;

 (6) using the absorbance value at the first wavelength or the absorbance value at the second wavelength measured in the step (5) or the ratio of the absorbance value at the first wavelength to the absorbance value at the second wavelength or at the third wavelength The fluorescence intensity value is found in the potassium ion concentration standard curve obtained in the step (3), and the potassium ion concentration value of the corresponding test solution is found, and then the potassium ion concentration of the sample to be tested is calculated by the dilution factor of the sample to be tested.

 The method of the present invention can be conveniently used to detect the concentration of potassium ions in various solution samples, for example, to detect the concentration of potassium ions in blood, urine or other body fluids of humans or animals.

 Since many other metal ions exist in addition to potassium ions in the human or animal body, the presence of sodium ions has a certain influence on the accuracy of the method of the present invention.

 Accordingly, a second aspect of the invention provides a method of detecting potassium ion concentration in a liquid sample in the context of sodium ions, the method comprising the steps of:

 (1) preparing a plurality of solution samples having different potassium ion concentrations using a buffer solution having a pH of 6.2 to 8.2, wherein each of the solution samples contains the same concentration of a DNA molecule capable of forming a G-quadruplex, the same concentration of sodium Ions and the same concentration of cyanine dyes;

 (2) placing the plurality of solution samples under an ultraviolet visible light absorption spectrometer or a spectrophotometer, detecting an absorbance value of the solution sample at the first wavelength and the fourth wavelength, or placing the plurality of solution samples The fluorescence intensity value of the wavelength at the third wavelength is detected by a fluorescence spectrometer using an excitation wavelength of 560 nm, wherein the first wavelength is in the range of 560 nm to 590 nm, and the fourth wavelength is in the range of 610 nm to 670 nm, the third wavelength In the range of 580 nm to 640 nm;

 (3) taking the potassium ion concentration of each of the solution samples as the abscissa or the ordinate, and measuring the absorbance value at the first wavelength or the absorbance value at the fourth wavelength of each solution sample measured in the step (2) or A ratio of the absorbance value at one wavelength to the absorbance value at the fourth wavelength or the fluorescence intensity at the third wavelength is plotted on the ordinate or abscissa to obtain a standard curve of potassium ion concentration;

 (4) adding a DNA molecule capable of forming a G-quadruplex, a compound of the formula I, and a buffer to the liquid sample to be tested, so that the concentration of the DNA molecule capable of forming the G-quadruplex in the liquid sample to be tested, The concentration of the compound of formula I and the pH value are identical to the solution sample in step (1), thereby obtaining a test solution;

(5) placing the test solution obtained in the step (4) under an ultraviolet visible light absorption spectrometer or a spectrophotometer, and detecting an absorbance value of the test solution at the first wavelength and the fourth wavelength, or The test solution is placed under a fluorescence spectrometer, and an excitation wavelength of 560 nm is used to detect a fluorescence intensity value at the third wavelength; (6) using the absorbance value at the first wavelength or the absorbance value at the fourth wavelength measured in the step (5) or the ratio of the absorbance value at the first wavelength to the absorbance value at the fourth wavelength or at the third wavelength The fluorescence intensity value is found in the potassium ion concentration standard curve obtained in the step (3), and the potassium ion concentration value of the corresponding test solution is found, and then the potassium ion concentration of the sample to be tested is calculated by the dilution factor of the sample to be tested.

 A third aspect of the invention provides a method of detecting a range of potassium ion concentrations in a liquid sample, the method comprising the steps of:

 (1) Preparing a plurality of solution samples with a buffer concentration of 6.2 to 8.2 with a certain potassium ion concentration gradient, wherein each of the solution samples contains the same concentration of DNA molecules capable of forming a G-quadruplex, the same concentration Sodium ion and the same concentration of cyanine dye; the prepared solution sample is used as a standard colorimetric sample;

 (2) adding a DNA molecule capable of forming a G-quadruplex, a cyanine dye, and a buffer to the liquid sample to be tested, so that the concentration of the DNA molecule capable of forming the G-quadruplex in the liquid sample to be tested, the cyanine dye The concentration and the pH value are the same as the solution sample in the step (1), thereby obtaining a test solution, and recording the proportion of the liquid sample to be tested to be diluted;

 (3) comparing the test solution with the color of the standard colorimetric sample obtained in the step (1), the potassium ion concentration of the standard colorimetric sample having the same color as the test solution is consistent with the potassium ion concentration of the test solution, and passes the test The dilution ratio of the sample is used to calculate the potassium ion concentration of the sample to be tested.

 The method according to the first aspect of the invention, wherein the buffer is selected from the group consisting of tris buffer, hydrochloric acid-borax buffer, triethanolamine buffer, imidazole-hydrochloric acid buffer, and glycine buffer Or 2-amino-2-methyl-μ propanol buffer.

 The method according to the second and third aspects of the present invention, wherein the buffer is selected from the group consisting of trishydroxymethylaminomethane

- Tris-HCl buffer, boric acid-borax buffer, triethanolamine buffer, imidazole-hydrochloric acid buffer, glycine buffer, 2-amino-2-methyl-1-propanol buffer, Sodium phosphate-sodium hydrogen phosphate buffer, barbital sodium-hydrochloric acid buffer, citric acid-sodium citrate buffer, glycine-sodium hydroxide buffer, borax-sodium hydroxide buffer or sodium phosphate buffer.

 In the embodiment of the present invention, the concentration of the buffer in the buffer is not particularly limited, but a preferred concentration range is 10 to 50 mmol/L.

The method according to the first, second and third aspects of the present invention, wherein the cyanine dye is a compound of the following formula I

 Formula I

Wherein: _"6 is alkyl, phenyl, alkyl-substituted phenyl; R _2, R _3, and R _{5 are} independently selected from H or dC ₆ alkyl, or R ₂ and R ₃ are attached to them The carbon atoms together form a 5- to 7-membered ring structure, or form a 5- to 7-membered ring structure together with R ₅ and the carbon atom to which they are attached; and R ₇ is a dC ₆ alkyl or sulfonate substituted dC ₆ alkyl; Y is a counter ion, and varies according to the charge of R ₇ . If R ₇ is an alkyl group, Y is a halogen anion; if only one of R ₇ has a sulfonate, Y is not required. As a counterion; if both R ₇ and a sulfonate, Y is a triethylamine cation; Xi, X _{2 is} independently selected from carbon (C), oxygen (0), sulfur (S), selenium (Se) or碲 (Te).

The method according to the first, second and third aspects of the present invention, wherein the alkyl group of dC ₆ is a linear or branched alkyl group having 1 to 6 carbon atoms, including but not limited to methyl group Base, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, n-hexyl or isohexyl.

 The method according to the first, second and third aspects of the invention, which is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, iso Butyl, n-hexyl, isohexyl, phenyl, methylphenyl or dimethylphenyl.

The method according to the first, second and third aspects of the invention, wherein R ₂ , R ₃ , and R _{5 are} independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, and iso Butyl, tert-butyl, pentyl, isopentyl, n-hexyl or isohexyl.

The method according to the first, second and third aspects of the invention, wherein R ₂ and R ₃ and the carbon atom to which they are attached may form a 5- to 7-membered saturated ring structure or an unsaturated ring structure, said ring The structure may or may not contain nitrogen (N) or sulfur (S) atoms.

The method according to the first, second and third aspects of the present invention, wherein R ₅ and the carbon atom to which they are attached may form a 5- to 7-membered saturated or unsaturated ring structure, and the ring structure may contain or Does not contain N or S atoms.

 The method according to the first, second and third aspects of the invention, wherein Y is preferably a fluorine, chlorine, bromine, iodine anion or triethylamine cation.

According to the methods of the first, second and third aspects of the invention, wherein the plurality of solution samples can be formulated by using a soluble potassium salt such as potassium chloride, potassium sulfate, potassium nitrate or the like, potassium ions in each solution sample Concentration The range is preferably in the range of 0 to 300 mmol/L, further preferably in the range of 0 to 200 mmol/L, still more preferably in the range of 0 to 150 mmol/L, and most preferably in the range of 20 to 100 mmol/L, wherein Non-limiting examples of soluble potassium salts include potassium chloride, potassium bromide, potassium iodide, potassium sulfate or potassium nitrate.

 The method according to the second or third aspect of the present invention, wherein the sodium ion concentration in the plurality of solution samples is preferably controlled within a physiological concentration range of the human or animal body, for example, a range of 0 to 300 mmol/L, preferably 10 to 200 mmol/L, more preferably in the range of 40 to 160 mmol/L, the concentration of sodium ions may be adjusted by adding a soluble sodium salt or using a buffer containing sodium ions, non-limiting examples of which include , sodium chloride, sodium bromide, sodium iodide, sodium sulfate or sodium nitrate.

 The method according to the first, second and third aspects of the present invention, wherein the concentration of the cyanine dye in the solution sample is in the range of 3 to 20 μm η 1 /ί, preferably 5 to ΙΟμιηοΙ / ί, which is capable of forming G The concentration of the tetra-stranded DNA molecule in the solution sample is in the range of 3 to 30 μm × 1 /ί, preferably 5 to 20 μιηο 1 /ί, and further preferably 10 to 20 μιηο 1 /ί.

 The method according to the first, second and third aspects of the present invention, wherein the DNA molecule capable of forming a G-quadruplex is a guanine-rich DNA molecule in a molecular sequence, and preferably has a molecular sequence GG" structure of DNA molecules. In such a DNA molecule, four guanines can form a planar four-collection by hydrogen bonding, and two or more planar four-collectiles can be stacked on each other to form a three-dimensional four-strand structure, that is, a guanine quadruplex (G-quadruplex). ). Non-limiting examples of such molecules include DNA, such as commercially available from Invitrogen Biotechnology Co. TTAGGGTTAGGG, TTAGGGTTAGGGTTAGGGTTAGGGTTAGGG, AGGGTTAGGGTTAGGGTTAGGG, TGAGGGTGGGGAGGGTGGGGAA, AGGGAGGGCGCTGGGAGGAGGG, GGGCGCGGGAGGAATTGGGCGGG, GGTTGGTGTGGTTGG, TTGGGGTTGGGGTTGGGGTTGGGG, TTGGGGTTGGGG, GGGGTTGGGG, GGGCGCGGGAGGAAGGGGGCGGG or

A DNA molecule such as GGGCGCGGGAGGAATTGGGCGGG, but the range of DNA sequence 歹 ij which can form a G-quadruplex is not limited by these enumerations. Further, the length of the DNA molecule capable of forming a G-quadruplex used in the present invention is not particularly limited, but is preferably 6 300 bases in length, more preferably 10 100 bases in length, and most preferably 10 30 The length of each base.

 A fourth aspect of the present invention provides a kit for carrying out the method of the present invention, the kit comprising: a buffer having a pH of 6.2 to 8.2, a soluble potassium salt, a DNA molecule capable of forming a G-quadruplex, and a cyanine dye.

 The kit according to the fourth aspect of the invention further comprises a soluble sodium salt.

The kit according to the fourth aspect of the present invention, further comprising a standard color chart, wherein different colors in the standard color chart correspond to different potassium ion concentrations. The color on the standard color chart can be determined by: (i) preparing a plurality of solution samples having different potassium ion concentrations using a buffer solution having a pH of 6.2 to 8.2, so that each of the solution samples contains the same concentration of a DNA molecule capable of forming a G quadruplex, and the same concentration of sodium ions. And the same concentration of cyanine dye; (ii) according to the solution sample potassium ion concentration from low to high order, and the color of the solution sample is collected by image acquisition means such as a digital camera and made into a standard color chart, on the color chart Different colors correspond to different potassium ion concentrations. In this case, when the kit is used to detect the potassium ion concentration in the sample to be tested, a DNA molecule capable of forming a G-quadruplex, a cyanine dye, a soluble sodium salt, and a buffer are added to the liquid sample to be tested, so that Measuring the concentration of the DNA molecule capable of forming the G-quadruplex in the liquid sample, the concentration of the cyanine dye, the sodium ion concentration, and the pH value are consistent with the solution sample prepared when determining the color of the standard color chart, thereby obtaining a test solution The potassium ion concentration range of the test solution is determined by comparing the color of the test solution with the color on the standard color chart, and the concentration range of the sample to be tested is obtained by the dilution factor of the sample to be tested.

 The kit according to the fourth aspect of the present invention, wherein the buffer, the soluble potassium salt, the soluble sodium salt, the DNA molecule capable of forming the G quadruplex, and the cyanine dye are as defined above.

 The method, kit and system according to the present invention, wherein for the compound of formula I, the preparation method can be referred to the synthetic route described in Leslie GS, Brooker and Frank LW, JACS, 1935, 547-551, or may be used. Other methods well known in the art are prepared.

 A fifth aspect of the invention provides a system for carrying out the method of the first and second aspects of the invention, the system comprising the kit of the fourth aspect of the invention and an ultraviolet visible light absorption spectrometer or a spectrophotometer or a fluorescence spectrometer.

 The main advantages of the method and kit of the invention are:

 1) The present invention utilizes a cyanine dye supramolecular aggregate to specifically recognize a potassium-regulated G-quadruplex structure, which can be operated under physiological sodium ion concentration without being affected, and has high specificity for potassium ions;

 2) The present invention uses a cyanine dye supramolecular probe, which is sensitive to the change of potassium-regulated G-quadruplex structure, accompanied by a change in aggregate morphology, and exhibits an absorption band up to a displacement of nearly one hundred nanometers in the ultraviolet absorption spectrum. , thus producing a change in color, enabling visual detection;

 3) The cyanine dye supramolecules used in the present invention can produce significant changes in both ultraviolet absorption spectrum and fluorescence spectrum, and can be quantitatively detected by an ordinary ultraviolet absorption spectrometer or a spectrophotometer or a fluorescence spectrometer, and no special or additional instruments are required. , the test cost is low, and it is convenient for promotion and application in the industry;

 4) The reagent components used in the present invention are only 3 to 4 kinds, and can be detected by instruments only when mixed in proportion, and the operation is simple, quick, and low in cost, and the system operates in a buffer environment without polluting the environment.

 5) The reagents used in the invention are simple in composition, small in variety, have no influence on each other, and have good stability, and can be stored for a long time, which can ensure the application test effect well;

6) The detection method provided by the invention can be used to form various forms such as liquid reagent, dry powder reagent and dry reagent. A reagent that can be used to measure potassium levels in humans and other animals. It can also be used to detect potassium levels in other samples such as water or soil.

 7) The detection method provided by the present invention can be developed into a test paper according to the color change characteristics of the cyanine dye aggregate, which makes the detection simpler and more convenient.

 8) Using the method of the present invention, the potassium ion concentration in samples of various concentration ranges can be analyzed by different dilution factors. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a potassium ion concentration standard curve according to Example 1 of the present invention;

 Figure 2 is a standard curve of potassium ion concentration according to Example 2 of the present invention;

 Figure 3 is a standard curve of potassium ion concentration according to Example 3 of the present invention;

 Figure 4 is a standard curve of potassium ion concentration according to Example 4 of the present invention;

 Figure 5 is a potassium ion concentration standard curve according to Example 9 of the present invention;

 Figure 6 is a potassium ion concentration standard curve according to Example 10 of the present invention;

 Figure 7 is a potassium ion concentration standard curve according to Example 11 of the present invention;

 Figure 8 is a standard curve of potassium ion concentration according to Example 12 of the present invention. The present invention will be described in more detail by way of specific embodiments thereof with reference to the accompanying drawings. The present invention may be practiced by those skilled in the art, and the scope of the invention should not be limited to the specific embodiments set forth herein. The instruments used in the examples of the present invention are: UV-visible absorption spectrometer, model Agilent 8453 UV-visible spectrophotometer; fluorescence spectrometer, model Hitachi F4500 spectrofluorometer (Japan).

 Example 1

The DNA capable of forming a G-quadruplex used in the present example is AGGGTTAGGGTTAGGGTTAGGG, and the cyanine dye used is a compound of the following formula

 1) Preparation of standard solution samples and test solutions

 A certain amount of DNA was dissolved in Tris-HCl buffer at pH 6.2 to prepare a mother liquor at a concentration of 200 μιηο/ί DNA for use.

 300 μί of a methanol solution having a concentration of 200 μm ηο 1 / phthalocyanine dye was added, 19.2 ml of Tris-HCl buffer was added, and then 300 μί of the DNA solution was added thereto. The above sample was equally divided into 10 portions, and each sample solution was 1.98 mL.

 Take 6 samples and add a certain amount of KC1 solution with a concentration of 200mmol/L, then dilute to 2mL with Tris-HCl buffer to obtain potassium ions with concentrations of 0, 0.05, 0.1, 0.25, 0.5, respectively. 0.8 mmol/L standard solution sample.

 In the other 4 samples, 20 μί of the urine sample to be tested was added to obtain 4 test solutions, and the urine sample accounted for 1% of the test solution.

 The above samples were placed in the dark and reserved.

 2) Detection and analysis

 The above samples were each analyzed by an ultraviolet absorption spectrometer. Everything is done at room temperature without additional conditions. The ultraviolet absorption spectrum collects data at a wavelength of 400 to 800 nm.

 3) Analysis of results

 The absorbance (at the 580 nm) of the standard sample is plotted on the abscissa and the potassium ion concentration of the standard sample is plotted on the ordinate to obtain a standard curve of the potassium ion concentration, as shown in Fig. 1. Using the absorbance at 580 nm of the test solution, the potassium ion concentration of the corresponding test solution can be found on the standard curve, and this value is divided by 1% to obtain the potassium ion concentration value of the urine sample to be tested. The results are shown in Table 1 below.

 Table 1

 Sample to be tested Concentration obtained by Ai mmol/L Actual concentration mmol/L Urine sample 1 33. 28 32. 76

 Urine sample 2 51. 29 53. 93

Urine sample 3 70. 56 72. 53

 Example 2

 The DNA which can be used to form the G quadruplex in this example is TGAGGGTGGGG

 1) Preparation of standard solution samples and test solutions

A certain amount of DNA was dissolved in a boric acid-borax buffer solution having a pH of 8.2 to prepare a mother liquor having a concentration of 200 μm _Ο 1 /ί DNA, and was used.

 300 μί of a methanol solution having a concentration of 600 μιηο 1 / phthalocyanine dye was added, 19.2 ml of a boric acid-borax buffer solution was added, and then 300 μί of a DNA solution was added thereto to mix. The above sample was equally divided into 10 portions, and each sample solution was 1.98 mL.

 Take 6 samples and add a certain amount of KC1 solution with a concentration of 200mmol/L, then dilute to 2mL with boric acid-borax buffer to obtain potassium ions with concentrations of 0, 0.05, 0.1, 0.25, 0.5, respectively. 0.8 mmol/L standard solution sample.

 In the other 4 samples, 20 μί of the urine sample to be tested was added to obtain 4 test solutions, and the urine sample accounted for 1% of the test solution.

 2) Detection and analysis

 The above samples were each analyzed by an ultraviolet absorption spectrometer. Everything is done at room temperature without additional conditions. The ultraviolet absorption spectrum collects data at a wavelength of 400 to 800 nm.

 3) Analysis of results

The ratio of the absorbance at 580 nm of the standard sample to the absorbance at 530 nm (/ ₂ ) is plotted on the ordinate, and the potassium ion concentration of the standard sample is plotted on the abscissa to obtain a standard curve of potassium ion concentration, as shown in Fig. 2. Using the ratio of the absorbance at 580 nm of the test solution to the absorbance at 530 nm, the potassium ion concentration value of the corresponding test solution can be found on the standard curve, and this is divided by 1% to obtain the potassium ion concentration value of the urine sample to be tested. Table 2. Table 2

 Example 3

 The DNA which can be used to form the G four chain in this example is GGGCCAGGGAG compound.

 1) Preparation of standard solution samples and test solutions

 A certain amount of DNA was dissolved in Tris-HCl buffer at pH 7.2 to prepare a mother liquor at a concentration of 600 μιηο/ί DNA, and was used.

 Take 300 μL of methanol solution with a concentration of 1.2 mmol/L cyanine dye, add 19.2 ml of Tris-HCl buffer, and then add 300 μί of DNA solution to mix. The above sample was equally divided into 10 portions, and each sample solution was 1.98 mL.

 Take 6 samples and add a certain amount of KC1 solution with a concentration of 200mmol/L, then dilute to 2mL with Tris-HCl buffer to obtain potassium ions with concentrations of 0, 0.05, 0.1, 0.25, 0.5, respectively. 0.8 mmol/L standard solution sample.

 In the other 4 samples, 20 μί of the urine sample to be tested was added to obtain 4 test solutions, and the urine sample accounted for 1% of the test solution.

 The above samples were placed in the dark and reserved.

 2) Detection and analysis

 The above samples were each analyzed by an ultraviolet absorption spectrometer. Everything is done at room temperature without additional conditions. The ultraviolet absorption spectrum collects data at a wavelength of 400 to 800 nm.

3) Analysis of results Taking the absorbance (A ₂ ) of the standard sample at 530 nm as the ordinate and the potassium ion concentration of the standard sample as the abscissa, a standard curve of the potassium ion concentration is obtained, as shown in FIG. 3 . The potassium ion concentration value of the corresponding test solution was found on the standard curve using the absorbance at 530 nm of the test solution, and this was divided by 1% to obtain the potassium ion concentration value of the urine sample to be tested. The results are shown in Table 3 below.

 table 3

 Example 4

 The DNA capable of forming a G quadruplex used in the present example is AGGGTT, and the cyanine dye used is a compound of the following formula

 1) Preparation of standard solution samples and test solutions

 A certain amount of DNA was dissolved in a pH 7.0 7.0 Tris-HCl buffer to prepare a 1.2 mmol/L DNA stock solution for use.

 300 μί of a methanol solution having a concentration of 200 μm ηο 1 / phthalocyanine dye was added, 19.2 ml of Tris-HCl buffer was added, and then 300 μί of the DNA solution was added thereto. The above sample was equally divided into 10 portions, and each sample solution was 1.98 mL.

 Take 6 samples and add a certain amount of KC1 solution with a concentration of 200mmol/L.

The volume of the Tris-HCl buffer was adjusted to 2 mL, and a standard solution sample with potassium ions of 0, 0.05, 0.1, 0.25, 0.5, and 0.8 mmol/L was obtained.

 In the other 4 samples, 20 μί of the urine sample to be tested was added to obtain 4 test solutions, and the urine sample accounted for 1% of the test solution.

 The above samples were placed in the dark and reserved.

2) Detection and analysis The above sample fluorescence spectrometer was analyzed. Everything is done at room temperature without additional conditions. The fluorescence spectrum excitation wavelength is 560 nm, and the wavelength collection range is 570 to 720 nm.

 3) Analysis of results

 The fluorescence intensity (FI) at a wavelength of 580 nm of the standard sample is plotted on the abscissa and the potassium ion concentration of the standard sample is plotted on the ordinate to obtain a standard curve of the potassium ion concentration, as shown in FIG. Using the fluorescence intensity of the test solution, find the potassium ion concentration value of the corresponding test solution on the standard curve, and divide it by 1% to obtain the potassium ion concentration value of the urine sample to be tested. The results are shown in Table 4 below.

 Table 4

 Example 5

 Four serum samples were tested in the same manner as in Example 1, except that the DNA used was TTAGGG TT:

 The absorbance of the solution sample and the test solution at a wavelength of 590 nm was measured and recorded as .

 The results are shown in Table 5 below: Sample to be tested A, concentration obtained mmol/L actual concentration mmol/L serum sample 1 32. 67 28. 29

Serum sample 2 50. 13 45. 23 Serum sample 3 34. 12 37. 19

 Serum samples 4 21. 17 25. 87

 Example 6

 Four serum samples were tested in the same manner as in Example 2 except that the DNA used was AGGGTTA.

The absorbances of the solution sample and the test solution at a wavelength of 590 nm and 540 nm were measured and recorded as A ₂ , respectively.

 The results are shown in Table 6 below:

 Table 6

 Example 7

 Four serum samples were tested in the same manner as in Example 3, except that the combination of the following formula was used.

 Detect the absorbance of the solution sample and the test solution at a wavelength of 500 nm, denoted as A:

The results are shown in Table 7 below: The concentration of the sample to be tested is A ₂ , the concentration of mmol/L, the actual concentration of mmol/L.

 Serum samples 1 33. 12 28. 29

 Serum samples 2 50. 18 45. 23

 Serum samples 3 35. 45 37. 19

 Serum samples 4 24. 05 25. 87

 Example 8

 Four serum samples were tested using the same procedure as in Example 4 except that the following formula was used:

 Detect the fluorescence intensity of the solution sample and the test solution at a wavelength of 640 nm, denoted as FI

 The results are shown in Table 8 below:

 Table 8

 Example 9-16 was carried out in the background of sodium ions

 Example 9

 The DNA which can be used to form the G-quadruplex in the present example is AGGGTTAGGGTTAGGGTTAGGG, and the cyanine dye used is a compound of the following formula.

1 ) 配制标准溶液样本和测试溶液

1) Prepare standard solution samples and test solutions

 A certain amount of DNA sample was dissolved in Tris-HCl (Tris-Na) buffer (pH 6.2) containing 20 mmol/L NaCl, and a DNA mother solution having a concentration of 500 μmηο1/ί was prepared and used.

 300 μί of a methanol solution having a concentration of 200 μm ηο 1 / phthalocyanine dye was added, 19.38 ml of Tris-Na buffer was added, and then a DNA solution of 120 μί was added thereto. The above sample was equally divided into 10 portions, and each sample solution was 1.98 mL.

 Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 0.05, 0.1, 0.2. , 0.5, 1, 1.5 mmol / L of the standard sample solution.

 In the other three samples, 20 μί of the urine sample to be tested was added, and the urine sample accounted for 1% of the total solution sample.

 The above samples were placed in the dark and reserved.

 2) Detection and analysis

 The above samples were analyzed by an ultraviolet absorption spectrometer. Everything is done at room temperature without additional conditions. The ultraviolet absorption spectrum collects data at a wavelength of 400 to 800 nm.

 3) Analysis of results

 The absorbance of the standard solution sample at 560 nm (denoted as A is plotted on the abscissa and the potassium ion concentration of the standard solution sample is plotted on the ordinate to obtain a standard curve of potassium ion concentration, as shown in Figure 5. 580 nm with test solution The absorbance at the point can find the potassium ion concentration value of the corresponding test solution on the standard curve, and divide it by 1% to obtain the potassium ion concentration value of the urine sample to be tested. The results are shown in Table 9 below.

 Table 9

 Example 10

The DNA capable of forming a G-quadruplex used in the present example is AGGGTTAGGGTTAGGGTTAGGG, and the cyanine dye used is a compound of the following formula

1) Prepare standard solution samples and test solutions

 A certain amount of DNA was dissolved in Tris-HCl (Tris-Na) buffer (pH 8.2) containing 200 mmol/L NaCl to prepare a DNA mother liquor at a concentration of 1.5 mmol/L, and was used.

 300 μί of a methanol solution having a concentration of 600 μιηο 1 / phthalocyanine dye was added, 19.38 ml of Tris-Na buffer was added, and then a DNA solution of 120 μί was added and mixed. The above sample was equally divided into 10 portions, and each sample solution was 1.98 mL.

 Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 0.05, 0.1, 0.2. , 0.5, 1, 1.5 mmol / L of the standard sample solution.

 In the other three samples, 20 μί of the urine sample to be tested was added, and the urine sample accounted for 1% of the total solution sample.

 The above samples were placed in the dark and reserved.

 2) Detection and analysis

 The above samples were each analyzed by an ultraviolet absorption spectrometer. Everything is done at room temperature without additional conditions. The ultraviolet absorption spectrum collects data at a wavelength of 400 to 800 nm.

 3) Analysis of results

In a standard sample absorbance at 650nm (denoted as A ₃₎ as the abscissa, potassium ion concentration of the standard sample is plotted as the ordinate, a standard curve to obtain the concentration of potassium ions, as shown in FIG. Using the absorbance at 650 nm of the test solution, the potassium ion concentration value of the corresponding test solution can be found on the standard curve, and this is divided by 1% to obtain the potassium ion concentration value of the urine sample to be tested. The results are shown in Table 10 below.

 Table 10

Example 11 The DNA capable of forming a G quadruplex used in the present example is

GGGCCAGGGA compound

1) Prepare standard solution samples and test solutions

 Dissolve a certain amount of DNA in Tris-HCl (Tris-Na) buffer containing 160mmol/L NaCl

In (pH 7.0), a DNA mother liquor having a concentration of 50 (^mol/L) was prepared and used.

 300 μί of a methanol solution having a concentration of 200 μm ηο 1 / phthalocyanine dye was added, 19.38 ml of Tris-Na buffer was added, and then a DNA solution of 120 μί was added thereto. The above sample was equally divided into 10 portions, and each sample solution was 1.98 mL.

 Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 0.05, 0.1, 0.2. , 0.5, 1, 1.5 mmol / L of the standard sample solution.

 In the other three samples, 20 μί of the urine sample to be tested was added, and the urine sample accounted for 1% of the total solution sample.

 The above samples were placed in the dark and reserved.

 2) Detection and analysis

 The above samples were analyzed by an ultraviolet absorption spectrometer. Everything is done at room temperature without additional conditions. The ultraviolet absorption spectrum collects data at a wavelength of 400 to 800 nm.

 3) Analysis of results

The ratio of the absorbance ( ) at 560 nm of the standard sample to the absorbance (A ₃ ) at 670 nm ( / A ₃ ) is plotted on the abscissa, and the potassium ion concentration of the standard solution sample is plotted on the ordinate to obtain the standard of potassium ion concentration. The curve is shown in Figure 7. Using the ratio of the absorbance at 560 nm of the test solution to the absorbance at 670 nm (Ai /A ₃ ), the potassium ion concentration of the corresponding test solution can be found on the standard curve, and this is divided by 1% to obtain the potassium of the urine sample to be tested. The ion concentration values are shown in Table 11 below.

 Table 11

The concentration of the sample to be tested is obtained by At/A ₃ mmol/L actual concentration mmol/L urine sample 1 28. 37 31. 17 Urine sample 2 36. 76 39. 71

 Urine sample 3 20. 43 21. 76

 Example 12

 The G-quadruplex can be formed in this embodiment.

 GGGCGCGGGAGGAATTGGGCGGG, the cyanine dye used is a compound of the formula

 1) Prepare standard solution samples and test solutions

 A certain amount of DNA was dissolved in Tris-HCl (Tris-Na) buffer containing 40 mmol/L NaCl to prepare a DNA mother liquor at a concentration of 3 mmol/L, and was used.

 Take 300 μί of a methanol solution of 1.2 mmol/L cyanine dye, add 19.38 ml of Tris-Na buffer, and then add 120 μί of the DNA solution to mix. The above sample was equally divided into 10 portions, and each sample solution was 1.98 mL.

 Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 0.05, 0.1, 0.2. , 0.5, 1, 1.5 mmol / L of the standard sample solution.

 In the other three samples, 20 μί of the urine sample to be tested was added, and the urine sample accounted for 1% of the total solution sample.

 The above samples were placed in the dark and reserved.

 2) Detection and analysis

 The above samples were analyzed by a fluorescence spectrometer. Everything is done at room temperature without additional conditions. The fluorescence spectrum has an excitation wavelength of 560 nm and a wavelength collection range of 570 to 720 nm.

 3) Analysis of results

 The fluorescence intensity of the standard sample at 640 nm (denoted as FI) is plotted on the abscissa and the potassium ion concentration of the standard solution sample is plotted on the ordinate to obtain a standard curve of potassium ion concentration, as shown in Fig. 8. Using the fluorescence intensity at 640 nm of the test solution, the potassium ion concentration value of the corresponding test solution can be found on the standard curve, and it is divided by 1% to obtain the potassium ion concentration value of the urine sample to be tested. The results are shown in Table 12 below.

 Table 12

The concentration of the sample to be tested is obtained by FI. The concentration of mmol/L is actually the concentration of mmol/L. Urine sample 1 32. 14 31. 17

 Urine sample 2 38. 72 39. 71

 Urine sample 3 19. 85 21. 76

 Example 13

 Three serum samples were tested in the same manner as in Example 9, except that the DNA used was GGGCGC.

检测溶液样本和测试溶液在波长 590nm处的吸光度， 记为 。

The absorbance of the solution sample and the test solution at a wavelength of 590 nm was measured and recorded.

 The results are shown in Table 13 below:

 Table 13

 Example 14

Three serum samples were tested in the same manner as in Example 10 except that the DNA used was GGGCGCGGGAGGAAGGGGGCGGG, and the cyanine dye used was a compound of the formula:

检测溶液样本和测试溶液在波长 670nm处的吸光度， 记为 A₃。

The absorbance of the solution sample and the test solution at a wavelength of 670 nm was measured and recorded as A ₃ .

 The results are shown in Table 14 below:

 Table 14

 Example 15

 Three serum samples were tested in the same manner as in Example 11 except that the DNA GGGGTTGGGG was used.

检测溶液样本和测试溶液在波长 580nm和 610nm处的吸光度， 分别记为

Detecting the absorbance of the solution sample and the test solution at wavelengths of 580 nm and 610 nm, respectively,

A ₃ .

 The results are shown in Table 15 below:

 Table 15

Example 16 Three serum samples were tested in the same manner as in Example 12 except that the DNA used was TTGGGGTTGG

检测溶液样本和测试溶液在波长 600nm处的荧光强度， 记为 FI。

The fluorescence intensity of the solution sample and the test solution at a wavelength of 600 nm was measured and recorded as FI.

 The results are as follows 16:

 Table 16

 Example 17

 In this example, the potassium ion concentration of three urine samples was verified. The actual potassium ion concentration of each urine sample was as follows: urine sample 1 was 5.84 mmol/L, urine sample 2 was 22.25 mmol/L, and urine sample 3 was 38.17. Mmmol/L. The DNA capable of forming a G-quadruplex used in the present example is TTAGGGTTAGGGTTAGGGTTAGGG, the cyanine dye used.

1) Prepare a sample of standard solution

 A certain amount of DNA sample was dissolved in Tris-HCl (Tris-Na) buffer (pH 8.0) containing 20 mmol/L NaCl, and a DNA mother solution having a concentration of ΙΟΟμιηοΙ/L was prepared and used.

300 μί of a methanol solution having a concentration of 200 μm ηο 1 / phthalocyanine dye was added, and 9.1 ml of Tris-Na buffer was added thereto, followed by addition of a DNA solution of 600 μί. The above sample was equally divided into 10 portions, and each sample solution was 1 mL. Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 2, 4, 8 respectively. , 10, 15, 20 mmol/L standard sample solution. The color of the standard solution sample is as follows: The color of the standard solution sample of 0~10mmol/L gradually changes from blue to purple, and the color of the standard solution of 10~20mmol/L gradually changes from purple to red.

 2) Prepare test solution

 In the other three samples, 1 mL of the urine sample to be tested was added and made up to 2 mL with Tris-Na buffer to obtain 3 test solutions, and the urine sample in each test solution accounted for 50% of the volume of the test solution.

 3) Comparative analysis

 The color of the test solution was compared with the color of the standard solution sample, and it was found that the color of the test solution 1 was blue, the test solution 2 was purple, and the color of the test solution 3 was pink. Therefore, the potassium ion concentration of the test solution 1 is in the range of 0 to 10, and the potassium ion concentration of the test solution 2 and the test solution 3 is in the range of 10 20 , and the potassium ion concentration of the urine sample 1 can be obtained from 0 to 20 by dilution ratio conversion. The range of urine sample 2 and urine sample 3 has a potassium ion concentration in the range of 20 to 40. This result is in agreement with the actual concentration of the urine sample.

 Example 18

 In this example, the potassium ion concentration of three urine samples was verified. The actual potassium ion concentration of each urine sample was as follows: urine sample 1 was 9.18 mmol/L, urine sample 2 was 32.43 mmol/L, urine sample 3 was 49.57 mmol. /L. The DNA capable of forming a G-quadruplex used in the present example is AGGGTTAGGGTTAGGGTTAGGG, the cyanine dye used.

1) Prepare a sample of standard solution

 A certain amount of DNA sample was dissolved in Tris-HCl (Tris-Na) buffer (pH 6.2) containing 40 mmol/L NaCl to prepare a DNA mother solution at a concentration of 500 μmηο1/ί, and was used.

[01] 300 μί of a methanol solution having a concentration of 200 μm ηο 1 / phthalocyanine dye was added, 9.14 ml of Tris-Na buffer was added, and then a DNA solution was added thereto to mix 360 μί. The above sample was equally divided into 10 portions, and each sample solution was 0.98 mL. Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 5, 10, 15 respectively. , 20, 30, 40mmol / L standard sample solution. The color of the standard solution sample is as follows: The color of the standard solution sample of 0~15mmol/L gradually changes from blue to purple, and the color of the standard solution of 15~40mmol/L gradually changes from purple to pink.

 2) Prepare test solution

 In the other three samples, 1 mL of the urine sample to be tested was added and made up to 2 mL with Tris-Na buffer to obtain 3 test solutions, and the urine sample in each test solution accounted for 50% of the volume of the test solution.

 3) Comparative analysis

 The color of the test solution was compared with the color of the standard solution sample, and it was found that the color of the test solution 1 was blue, the test solution 2 was purple, and the test solution 3 was pink. Therefore, the potassium ion concentration of the test solution 1 is in the range of 0 to 15, and the potassium ion concentration of the test solution 2 and the test solution 3 is in the range of 15 40. The potassium ion concentration of the urine sample 1 can be obtained from 0 to 30 by dilution ratio conversion. The range of urine sample 2 and urine sample 3 has a potassium ion concentration in the range of 30 80 . This result is in agreement with the actual concentration of the urine sample.

 Example 19

 In this example, the potassium ion concentration of three urine samples was verified. The actual potassium ion concentration of each urine sample was as follows: urine sample 1 was 9.82 mmol/L, urine sample 2 was 20.35 mmol/L, and urine sample 3 was 78.26. Mmmol/L. The DNA which can be used to form a G-quadruplex in this example is TTAGGG TTAGGGTTAGG

1) Prepare a sample of standard solution

 A certain amount of DNA sample was dissolved in Tris-HCl (Tris-Na) buffer (pH 7.5) containing 100 mmol/L NaCl to prepare a DNA mother liquor having a concentration of 500 μmηο1/ί, and was used.

0.4 mL of a methanol solution having a concentration of 200 μιηο 1 / phthalocyanine dye was added, 4.2 ml of Tris-Na buffer was added, and then 0.4 mL of the DNA solution was added and mixed. The above sample was equally divided into 10 portions, and each sample solution was 0.5 mL. Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 10, 20, 40 respectively. , 60, 80, 100 mmol / L standard sample solution. The color of the standard solution sample is as follows: The color of the standard solution sample of 0~60mmol/L gradually changes from blue to purple, and the color of the standard solution of 60~100mmol/L gradually changes from purple to red.

 2) Prepare test solution

 In the other three samples, 1.5 mL of the urine sample to be tested was added to obtain three test solutions, and the urine sample in each test solution accounted for 75% of the volume of the test solution.

 3) Comparative analysis

 The color of the test solution was compared with the color of the standard solution sample, and it was found that the colors of the test solutions 1 and 2 were blue, and the color of the test solution 3 was purple. Therefore, the potassium ion concentration of the test solutions 1, 2, 3 is in the range of 0-60, and the potassium ion concentration of the urine samples 1, 2, 3 can be obtained in the range of 0 to 80 by dilution ratio conversion. This result is in agreement with the actual concentration of the urine sample.

 Example 20

 In this example, the potassium ion concentration of three urine samples was verified. The actual potassium ion concentration of each urine sample was as follows: urine sample 1 was 42.58 mmol/L, urine sample 2 was 70.65 mmol/L, and urine sample 3 was 98.34. Mmmol/L. The DNA capable of forming a G-quadruplex used in the present example is AGGGTTAGGGTTAGGGTTAGGG, the cyanine dye used.

 1) Prepare a sample of standard solution

 A certain amount of DNA sample was dissolved in Tris-HCl (Tris-Na) buffer (pH 8.2) containing 160 mmol/L NaCl to prepare a DNA mother liquor having a concentration of 500 μm ηο/ί, and was used.

 Take 0.5 mL of methanol solution with a concentration of 200 μιηο1 / phthalocyanine dye, add 3.5 ml of Tris-Na buffer, and then add 1 mL of DNA solution to mix. The above sample was equally divided into 10 portions, and each sample solution was 0.5 mL.

Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 20, 50, 75 respectively. , 100, 125, 160 mmol / L standard sample solution. The color of the standard solution sample is as follows: The color of the standard solution sample of 0~100mmol/L gradually changes from blue to purple, and the color of the standard solution of 100~125mmol/L gradually changes from purple to pink.

 2) Prepare test solution

 Add 1.5 mL of the urine sample to be tested to the other 3 samples and dilute to 2 mL with Tris-Na buffer.

For each of the three test solutions, the urine sample in each test solution accounted for 75% of the volume of the test solution.

 3) Comparative analysis

 The color of the test solution was compared with the color of the standard solution sample, and it was found that the color of the test solution 1 was blue, and the color of the test solution 2 and the test solution 3 was purple. Therefore, the potassium ion concentration of the test solutions 1, 2, and 3 is in the range of 0 to 100. The dilution ratio can be used to obtain the potassium ion concentration of the urine samples 1, 2, and 3 in the range of 0 to 133, and the urine sample 2, 3 potassium. The ion concentration is higher than the urine sample 1 potassium ion concentration. This result is in agreement with the actual concentration of the urine sample.

 Example 21

 In this example, the potassium ion concentration of three urine samples was verified. The actual potassium ion concentration of each urine sample was as follows: urine sample 1 was 5.57 mmol/L, urine sample 2 was 23.24 mmol/L, and urine sample 3 was 39.16. Methyl/L, the DNA used as a compound:

1) Prepare a sample of standard solution

 A certain amount of DNA sample was dissolved in Tris-HCl (Tris-Na) buffer (pH 7.0) containing 20 mmol/L NaCl to prepare a DNA mother solution having a concentration of 20 (mol/L), which was used.

300 μί of a methanol solution having a concentration of 200 μm ηο 1 / phthalocyanine dye was added, and 8.5 ml of Tris-Na buffer was added thereto, followed by addition of a DNA solution of 600 μί. The above sample was equally divided into 10 portions, and each sample solution was 1 mL. Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 2, 4, 8 respectively. , 10, 15, 20 mmol/L standard sample solution. The color of the standard solution sample is as follows: The color of the standard solution sample of 0~10mmol/L gradually changes from blue to purple, and the color of the standard solution of 10~20mmol/L gradually changes from purple to red.

 2) Prepare test solution

 In the other three samples, 1 mL of the urine sample to be tested was added and made up to 2 mL with Tris-Na buffer to obtain 3 test solutions, and the urine sample in each test solution accounted for 50% of the volume of the test solution.

 3) Comparative analysis

 The color of the test solution was compared with the color of the standard solution sample, and it was found that the color of the test solution 1 was blue, the test solution 2 was purple, and the color of the test solution 3 was pink. Therefore, the potassium ion concentration of the test solution 1 is in the range of 0 to 10, and the potassium ion concentration of the test solution 2 and the test solution 3 is in the range of 10 20 , and the potassium ion concentration of the urine sample 1 can be obtained from 0 to 20 by dilution ratio conversion. The range of urine sample 2 and urine sample 3 has a potassium ion concentration in the range of 20 to 40. This result is in agreement with the actual concentration of the urine sample.

 Example 22

 In this example, the potassium ion concentration of three urine samples was verified. The actual potassium ion concentration of each urine sample was as follows: urine sample 1 was 85.32 mmol/L, urine sample 2 was 100.54 mmol/L, urine sample 3 was 126.32 mmol. /L, the DNA used is GGGCGCGGGAGGAAGGGGGCGGG, and the cyanine dye used is a compound of the formula:

1) Prepare a sample of standard solution

 A certain amount of DNA sample was dissolved in Tris-HCl (Tris-Na) buffer (pH 6.2) containing 300 mmol/L NaCl to prepare a DNA mother liquor having a concentration of 20 (mol/L), which was used.

Take 1 mL of a methanol solution having a concentration of 200 μιηο 1 / phthalocyanine dye, add 7 ml of Tris-Na buffer, and then add 2 mL of the DNA solution to mix. The above sample was equally divided into 10 portions, and each sample solution was 1 mL. Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 600mmol/L KC1, then dilute to 2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 50, 100, 150 respectively. , 200, 250, 300 mmol / L standard sample solution. The color of the standard solution sample is as follows: The color of the standard solution sample of 0~150mmol/L gradually changes from blue to purple, and the color of the standard solution of 150~300mmol/L gradually changes from purple to pink.

 2) Prepare test solution

 In the other three samples, 1 mL of the urine sample to be tested was added and made up to 2 mL with Tris-Na buffer to obtain 3 test solutions, and the urine sample in each test solution accounted for 50% of the volume of the test solution.

 3) Comparative analysis

 The color of the test solution was compared with the color of the standard solution sample, and it was found that the colors of the test solutions 1, 2, and 3 were blue. Therefore, the potassium ion concentration of the test solutions 1, 2, 3 is in the range of 0 150, and the potassium ion concentration of the three urine samples is in the range of 0 300 by the dilution ratio conversion. This result is in agreement with the actual concentration of the urine sample.

 Example 23

 In this example, the potassium ion concentration of three urine samples was verified. The actual potassium ion concentration of each urine sample was as follows: urine sample 1 was 23.52 mmol/L urine sample 2 was 45.28 mmol/L, and urine sample 3 was 64.83 mmol. /L, the DNA used is GGGG

1) Prepare a sample of standard solution

 A certain amount of DNA sample was dissolved in Tris-HCl (Tris-Na) buffer (ρΗ8.0) containing 10 mmol/L NaCl to prepare a DNA mother solution having a concentration of 200 μmηο1/ί, and was used.

 Take 0.5 mL of methanol solution with a concentration of 200 μιηο1 / phthalocyanine dye, add 8.5 ml of Tris-Na buffer, and then add 1 mL of DNA solution to mix. The above sample was equally divided into 10 portions, and each sample solution was 1 mL.

 Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 1.2mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 1, and 2. 4, 6, 8, 10 mmol/L standard sample solution. The color of the standard solution sample is as follows: The color of the standard solution sample of 0~6mmol/L gradually changes from blue to purple, and the color of the standard solution of 6~8mmol/L gradually changes from purple to red.

2) Prepare test solution In the other three samples, 200 μί of the urine sample to be tested was added to obtain three test solutions, and the urine sample in each test solution accounted for 17% of the volume of the test solution.

 3) Comparative analysis

 The color of the test solution was compared with the color of the standard solution sample, and it was found that the color of the test solution 1 was blue, and the color of the test solution 2 and the test solution 3 was pink. Therefore, the potassium ion concentration of the test solution 1 is in the range of 0-6, and the potassium ion concentration of the test solution 2 and the test solution 3 is in the range of 6-10, and the potassium ion concentration of the urine sample 1 can be obtained by the dilution ratio conversion. In the range of 35, the potassium ion concentration of urine sample 2 and urine sample 3 is in the range of 35 to 59. This result is in agreement with the actual concentration of the urine sample.

 Example 24

 In this example, the potassium ion concentration of three urine samples was verified. The actual potassium ion concentration of each urine sample was as follows: urine sample 1 was 22.36 mmol/L urine sample 2 was 48.72 mmol/L, and urine sample 3 was 52.38 mmol. /L, the DNA used is a compound whose GGG is of the formula:

1) Prepare a sample of standard solution

 Dissolve a certain amount of DNA sample in Tris-HCl (Tris-Na) buffer containing 50mmol/L NaCl

In pH (pH 6.2), a DNA stock solution of ΙΟΟμιηοΙ/L was prepared and used.

 200 μί of a methanol solution having a concentration of 200 μιηο 1 / phthalocyanine dye was added, 4.5 ml of Tris-Na buffer was added, and then 300 μί of a DNA solution was added thereto to mix. The above sample was equally divided into 10 portions, and each sample solution was 0.5 mL.

 Take 7 samples and add a certain amount of Tris-Na solution with a concentration of 200mmol/L KC1, then dilute to 1.5mL with Tris-Na buffer to obtain potassium ions with concentrations of 0, 10, 20, respectively. 30, 40, 50, 60 mmol/L standard sample solution. The color of the standard solution sample is as follows: The color of the standard solution sample of 0~30mmol/L gradually changes from blue to purple, and the color of the standard solution of 30~60mmol/L gradually changes from purple to pink.

 2) Prepare test solution

 In the other three samples, 1 mL of the urine sample to be tested was added to obtain three test solutions, and the urine sample in each test solution accounted for 66% of the volume of the test solution.

 3) Comparative analysis

Comparing the color of the test solution with the color of the standard solution sample, the color of the test solution 1 was found. In blue, the color of Test Solution 2 and Test Solution 3 is purple. Therefore, the potassium ion concentration of the test solution 1 is in the range of 0-30, and the potassium ion concentration of the test solution 2 and the test solution 3 is in the range of 30 60. The potassium ion concentration of the urine sample 1 can be obtained by the dilution ratio conversion from 0 to 45. The range of urine sample 2 and urine sample 3 has a potassium ion concentration in the range of 45 to 91. This result is in agreement with the actual concentration of the urine sample.

 One of the remarkable features of the present invention is: detection of changes in DNA conformation based on potassium ions, potassium ions cause DNA conformational changes, and DNA conformational changes cause changes in the aggregation pattern of cyanine dyes, resulting in solution color or absorption, fluorescence The spectrum changes. The system is simple in composition and simple in reaction. Potassium ion is the "initiator" of the whole reaction, which ensures the accuracy of the detection.

 A notable feature of the present invention is that the system itself can carry a large amount of sodium ions, which ensures that environmental changes caused by sodium ions in the sample are negligible.

 The third characteristic feature of the present invention is that the use of a cyanine dye supramolecular probe has high reaction sensitivity and color change, and can be visually observed.

 In summary, the experiment proves that the measurement method of the present invention can completely determine the concentration level of potassium ions in the sample by ultraviolet absorption spectrometer or fluorescence spectrometer, and has high test sensitivity, good specificity and good precision. At the same time, the level of potassium ion concentration can be judged by the naked eye by the change of the color of the solution. In addition, the potassium ion detection kit provided by the invention has good stability and can accurately detect the potassium ion content of various types of samples after long-term storage.

 Although the present invention has been described in terms of the specific embodiments thereof, it is apparent to those skilled in the art that the present invention can be carried out without departing from the spirit and scope of the invention as defined by the appended claims. Various changes and modifications are also included in the scope of the present invention.

Claims

Rights request A method of detecting a concentration of potassium ions in a liquid sample, the method comprising the steps of: (1) preparing a plurality of solution samples having different potassium ion concentrations using a buffer solution having a pH of 6.2 to 8.2, wherein each of the solution samples contains the same concentration of DNA molecules capable of forming a G-quadruplex and the same concentration of cyanine Dye  (2) placing the plurality of solution samples under an ultraviolet visible light absorption spectrometer or a spectrophotometer, detecting an absorbance value at the first wavelength and an absorbance value at the second wavelength, or placing the plurality of solution samples in the fluorescence Under the spectrometer, the excitation intensity of the wavelength at the third wavelength is detected using an excitation wavelength of 560 nm, wherein the first wavelength is in the range of 560 nm to 590 nm, and the second wavelength is in the range of 500 nm to 540 nm, and the third wavelength is 580nm to 640nm range;  (3) taking the potassium ion concentration of each of the solution samples as the abscissa or the ordinate, the absorbance value at the first wavelength or the absorbance value at the second wavelength measured in the step (2) or at the first wavelength Obtaining a ratio of the absorbance value to the absorbance value at the second wavelength or the fluorescence intensity at the third wavelength is plotted on the ordinate or the abscissa to obtain a standard curve of the potassium ion concentration;  (4) adding a DNA molecule capable of forming a G-quadruplex, a compound of the formula I, and a buffer to the liquid sample to be tested, so that the concentration of the DNA molecule capable of forming the G-quadruplex in the liquid sample to be tested, The concentration of the compound of formula I and the pH value are identical to the solution sample in step (1), thereby obtaining a test solution;  (5) placing the test solution obtained in the step (4) under an ultraviolet visible light absorption spectrometer or a spectrophotometer, detecting the absorbance value of the test solution at the first wavelength and the second wavelength, or placing the test solution on the fluorescence spectrometer The fluorescence intensity value at the third wavelength is detected by using an excitation wavelength of 560 nm; (6) using the absorbance value at the first wavelength or the absorbance value at the second wavelength measured in the step (5) or the ratio of the absorbance value at the first wavelength to the absorbance value at the second wavelength or at the third wavelength The fluorescence intensity value is found in the potassium ion concentration standard curve obtained in the step (3), and the potassium ion concentration value of the corresponding test solution is found, and then the potassium ion concentration of the sample to be tested is calculated by the dilution factor of the sample to be tested. 2. A method of detecting potassium ion concentration in a liquid sample in the context of sodium ions, the method comprising the steps of: (1) preparing a plurality of solution samples having different potassium ion concentrations by using a buffer solution of pH 6.2 to 8.2, wherein each of the solution samples contains the same concentration of DNA molecules capable of forming a G-quadruplex, the same concentration a sodium ion and a cyanine dye of the same concentration, wherein the sodium ion concentration in the solution sample is in the range of 10 to 200 mmol/L;  (2) placing the plurality of solution samples under an ultraviolet visible light absorption spectrometer or a spectrophotometer, detecting an absorbance value of the solution sample at the first wavelength and the fourth wavelength, or placing the plurality of solution samples The fluorescence intensity value of the wavelength at the third wavelength is detected by a fluorescence spectrometer using an excitation wavelength of 560 nm, wherein the first wavelength is in the range of 560 nm to 590 nm, and the fourth wavelength is in the range of 610 nm to 670 nm, the third wavelength In the range of 580 nm to 640 nm;  (3) taking the potassium ion concentration of each of the solution samples as the abscissa or the ordinate, and measuring the absorbance value at the first wavelength or the absorbance value at the fourth wavelength of each solution sample measured in the step (2) or the first A ratio of the absorbance value at one wavelength to the absorbance value at the fourth wavelength or the fluorescence intensity at the third wavelength is plotted on the ordinate or abscissa to obtain a standard curve of potassium ion concentration;  (4) adding a DNA molecule capable of forming a G-quadruplex, a compound of the formula I, and a buffer to the liquid sample to be tested, so that the concentration of the DNA molecule capable of forming the G-quadruplex in the liquid sample to be tested, The concentration of the compound of formula I and the pH value are identical to the solution sample in step (1), thereby obtaining a test solution;  (5) placing the test solution obtained in the step (4) under an ultraviolet visible light absorption spectrometer or a spectrophotometer, and detecting an absorbance value of the test solution at the first wavelength and the fourth wavelength, or The test solution is placed under a fluorescence spectrometer, and an excitation wavelength of 560 nm is used to detect a fluorescence intensity value at the third wavelength;  (6) using the absorbance value at the first wavelength or the absorbance value at the fourth wavelength measured in the step (5) or the ratio of the absorbance value at the first wavelength to the absorbance value at the fourth wavelength or at the third wavelength The fluorescence intensity value is found in the potassium ion concentration standard curve obtained in the step (3), and the potassium ion concentration value of the corresponding test solution is found, and then the potassium ion concentration of the sample to be tested is calculated by the dilution factor of the sample to be tested. 3. A method for detecting a concentration of potassium ions in a liquid sample, the method comprising the steps of: (1) preparing a plurality of solution samples with a buffer concentration of 6.2 to 8.2 with a certain potassium ion concentration gradient, wherein each of the solutions The solution sample contains the same concentration of DNA molecules capable of forming a G-quadruplex, the same concentration of sodium ions, and the same concentration of cyanine dyes; (2) adding a DNA molecule capable of forming a G-quadruplex, a cyanine dye, and a buffer to the liquid sample to be tested, so that the concentration of the DNA molecule capable of forming the G-quadruplex in the liquid sample to be tested, the cyanine dye The concentration and pH are the same as the solution sample in step (1), thereby obtaining the test solution and recording The proportion of the liquid sample to be tested that is diluted;  (3) comparing the test solution with the color of the standard colorimetric sample obtained in the step (1), the potassium ion concentration of the standard colorimetric sample having the same color as the test solution is consistent with the potassium ion concentration of the test solution, and passes the test The dilution ratio of the sample is used to calculate the potassium ion concentration of the sample to be tested. 4. The method according to claim 1, wherein the buffer is selected from the group consisting of tris buffer-hydrochloric acid buffer, boric acid-borax buffer, triethanolamine buffer, imidazole-hydrochloric acid buffer, and glycine Buffer or 2-amino-2-methyl-1-propanol buffer. The method according to claim 2 or 3, wherein the buffer is selected from the group consisting of tris buffer-hydrochloric acid buffer, boric acid-borax buffer, triethanolamine buffer, imidazole-hydrochloric acid buffer, and double sweet. Aminopeptide buffer, 2-amino-2-methyl-1-propanol buffer, sodium phosphate-sodium hydrogen phosphate buffer, barbital sodium-hydrochloric acid buffer, citric acid-sodium citrate buffer, glycine- Sodium hydroxide buffer, borax-sodium hydroxide buffer or sodium phosphate buffer. The method according to any one of claims 1 to 5, wherein the cyanine dye is a compound of the following formula I

 Formula I among them: ! ^为为. Alkyl, phenyl, alkyl substituted phenyl; R ₂ , R ₃ , and R _{5 are} independently selected from H or dC ₆ alkyl, or R ₂ and R ₃ are attached to the carbon atom to which they are attached Forming a 5- to 7-membered ring structure together, or forming a 5- to 7-membered ring structure together with R ₅ and the carbon atom to which they are attached; and R ₇ is a dC ₆ alkyl or sulfonate-substituted dC ₆ alkane Y is a counter ion, which differs depending on the charge carried by R ₇ . If R ₇ is an alkyl group, Y is a halogen anion; if only one of Re and R ₇ has a sulfonate group, Y is not required. Ion; if both R ₇ and sulfonate have a sulfonate, Y is a triethylamine cation; Xi, X _{2 is} independently selected from carbon, oxygen, sulfur, selenium or tellurium. 7. The method according to claim 6, wherein the alkyl group of dC ₆ is a linear or branched alkyl group having 1 to 6 carbon atoms, including, but not limited to, methyl, ethyl, n-propyl, Isopropyl, n-butyl, isobutyl, Tert-butyl, pentyl, isopentyl, n-hexyl or isohexyl. 8. The method according to claim 6, wherein it is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, n-hexyl, Isohexyl, phenyl, methylphenyl or dimethylphenyl. 9. The method of claim 6, wherein R ₂ , R ₃ , and R _{5 are} independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl , pentyl, isopentyl, n-hexyl or isohexyl. 10. The method according to claim 6, wherein R ₂ and R ₃ and the carbon atom to which they are attached may form a 5- to 7-membered saturated ring structure or an unsaturated ring structure, which may or may not contain Nitrogen or sulfur atom. 11. The method of claim 6, wherein R and R ₅ and the carbon atom to which they are attached may form a 5- or 7-membered saturated or unsaturated ring structure, said ring structure may or may not contain N or S atoms . 12. The method of claim 6, wherein Y is preferably a fluorine, chlorine, bromine, iodine anion or triethylamine cation. The method according to any one of claims 1 to 3, wherein a concentration of potassium ions in the solution sample is preferably in the range of 0 to 300 mmol/L, further preferably in the range of 0 to 200 mmol/L, It is still more preferably in the range of 0 to 150 mmol/L, and most preferably in the range of 20 to 100 mmol/L. The method according to claim 2 or 3, wherein the sodium ion concentration in the solution sample is in the range of 0 to 300 mmol/L, preferably 10 to 200 mmol/L, more preferably 40 to 160 mmol/L. . The method according to any one of claims 1 to 3, wherein the concentration of the cyanine dye in the solution sample is in the range of 3 to 20 μm η 1 /ί, preferably 5 to ΙΟμιηοΙ / ί, which is capable of forming G The concentration of the tetra-stranded DNA molecule in the solution sample is in the range of 3 to 30 μιηο 1 /ί, preferably 5 to 20 μιηο1/ί, and further preferably 10 to 20 μιηο1/ί. The method according to any one of claims 1 to 3, wherein the G-quadruplex capable of forming A DNA molecule is a DNA molecule having a "GG" structure in a molecular sequence. 17. The method according to claim 16, wherein said DNA molecule is selected from TTAGGGTTAGGG, TTAGGG TTAGGGTTAGGGTTAGGGTTAGGG, AGGGTTAGGGTTAGGGTTAGGG, TGAGGGTGGGGAGGGTGGGGAA, AGGGAGGGCGCTGGGAGGAGGG, GGGCGCGGGAGGAATTGGGCGGG, GGTTGGTGTGGTTGG, TTGGGGTTGGGGTTGGGGTTGGGG, TTGGGGTTGGGG, GGGGTTGGGG, GGGCGCGGGAGGAAGGGGGCGGG or GGGCGCGGGAGGAATTGGGCGGGo 18. A kit for detecting a concentration of potassium ions, the kit comprising: a buffer having a pH of 6.2 to 8.2, a soluble potassium salt, a DNA molecule capable of forming a G-quadruplex, and a cyanine dye. 19. The kit of claim 18, further comprising a soluble sodium salt. 20. The kit of claim 19, further comprising a standard color chart, wherein different colors in the standard color chart correspond to different potassium ion concentrations; the color on the standard color chart is obtained in the following manner Determine: (i) prepare a plurality of solution samples having different potassium ion concentrations with a buffer solution of pH 6.2 to 8.2, so that each of the solution samples contains the same concentration of DNA molecules capable of forming a G quadruplex, the same concentration Sodium ions and the same concentration of cyanine dyes; (ii) according to the order of potassium ion concentration of the solution sample, and collecting the color of the solution sample by image acquisition means such as a digital camera and making a standard color chart, colorimetric Different colors on the card correspond to different potassium ion concentrations. The kit according to any one of claims 18 to 20, wherein the cyanine dye is a compound of the following formula I

 Formula I Wherein: 1 is ₆ alkyl, phenyl, alkyl substituted phenyl; R ₂ , R ₃ , and R _{5 are} independently selected from H or dC ₆ alkyl, or R ₂ and R ₃ and Connected carbon atoms together form 5 yuan to a 7-membered ring structure, or a ring structure of 5 to 7 members formed by R ₅ together with the carbon atom to which they are attached; and R ₇ is a dC ₆ alkyl group or a sulfonic acid group substituted dC ₆ alkyl group; Ions, depending on the charge carried by R ₇ , if R ₇ is an alkyl group, Y is a halogen anion; if only one of Re and R ₇ has a sulfonate, Y is not required as a counter ion; ₇ has a sulfonate group, and Y is a triethylamine cation; Xi, X _{2 is} independently selected from carbon, oxygen, sulfur, selenium or tellurium. The kit according to claim 21, wherein the alkyl group of dC ₆ is a linear or branched alkyl group having 1 to 6 carbon atoms, including, but not limited to, methyl, ethyl or n-propyl groups. , isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, n-hexyl or isohexyl. The kit according to claim 21, which is selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, n-hexyl , isohexyl, phenyl, methylphenyl or dimethylphenyl. The kit according to claim 21, wherein R ₂ , R ₃ , and R _{5 are} independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl Base, pentyl, isopentyl, n-hexyl or isohexyl. The kit according to claim 21, wherein R ₂ and R ₃ and the carbon atom to which they are attached may form a 5- to 7-membered saturated ring structure or an unsaturated ring structure, and the ring structure may or may not be Contains nitrogen or sulfur atoms. 26. The kit according to claim 21, wherein R ₅ and the carbon atom to which they are attached may form a 5- to 7-membered saturated or unsaturated ring structure, the ring structure may contain or may not contain N or S atom. 27. The kit of claim 21, wherein Y is preferably a fluorine, chlorine, bromine, iodine anion or triethylamine cation. The kit according to any one of claims 18 to 20, wherein the DNA molecule capable of forming a G-quadruplex is a DNA molecule having a "GG" structure in a molecular sequence. 29. The kit according to claim 28, wherein said DNA molecule is selected from TTAGGGTTAGGG, TTAGGG TTAGGGTTAGGGTTAGGGTTAGGG, AGGGTTAGGGTTAGGGTTAGGG, TGAGGGTGGGGAGGGTGGGGAA, AGGGAGGGCGCTGGGAGGAGGG, GGGCGCGGGAGGAATTGGGCGGG, GGTTGGTGTGGTTGG, TTGGGGTTGGGGTTGGGGTTGGGG, TTGGGGTTGGGG, GGGGTTGGGG, GGGCGCGGGAGGAAGGGGGCGGG or GGGCGCGGGAGGAATTGGGCGGGo 30. A system for detecting a concentration of potassium ions, the system comprising the kit of any one of claims 18 to 29 and an ultraviolet visible light absorption spectrometer or a spectrophotometer or a fluorescence spectrometer.