Reagent, method, and device for detecting albumin

Abstract

To provide a reagent for detecting albumin, a method of detecting albumin in a sample using the same, and the like.SOLUTION: An aspect of the present disclosure relates to a reagent for detecting albumin, containing a terbium complex represented by a given formula. An aspect of the present disclosure also relates to a method of detecting albumin in a sample using the terbium complex represented by the given formula.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a reagent for detecting albumin, a method for detecting albumin in a sample, a terbium complex used for detecting albumin, an albumin detection device, a test paper for detecting albumin, and the like. [Background technology]

[0002] Albumin is a protein with a molecular weight of approximately 66,000, accounting for 50-65% of the proteins present in serum. Albumin maintains the osmotic pressure of blood and also binds to and transports hormones, fatty acids, drug molecules, metal ions, etc. Albumin is known to be associated with diseases such as kidney disease, cardiovascular disease, and liver disease.

[0003] In healthy individuals, albumin is filtered by the kidneys. However, if albumin is not properly filtered by the kidneys, it is excreted in the urine. For example, patients with diabetic nephropathy, a complication of diabetes, are known to have increased amounts of albumin in their urine. Therefore, urinary albumin levels can be used as an indicator for diabetic nephropathy diagnosis.

[0004] Known methods for detecting albumin include urine test strips and turbidimetric immunoassay (TIA). Detection methods utilizing the reaction between albumin and fluorescent organic compounds have also been reported. For example, Non-Patent Document 1 discloses that 4-[4-(4-dimethylaminophenyl)-5-phenyl-1H-imidazol-2-yl]benzoic acid methyl ester (DAPIM) has the fluorescent property of increasing its fluorescence upon specific binding to human serum albumin (HSA), and can be used to detect diabetic nephropathy. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Nagasaki University Graduate School of Biomedical Sciences, "Development of a New On-Site Screening Method for Early Detection of Diabetic Nephropathy: Aiming to Reduce the Number of Elderly Patients on Dialysis and Cut Medical Costs," Mitsui Sumitomo Insurance Welfare Foundation, Research Results Report, Vol. 17, 2011 Research Grant (published July 2013), Internet (URL: https: / / www.ms-ins.com / welfare / document / list / list2011.htm, https: / / www.ms-ins.com / welfare / document / list / pdf / 2011 / 4_1_04.pdf) Summary of the Invention [Problem to be solved by the invention]

[0006] However, there is room for improvement in terms of sensitivity in the albumin detection method of Non-Patent Document 1. Therefore, an object of one aspect of the present disclosure is to provide a reagent for detecting albumin, a method for detecting albumin in a sample, an albumin detection device, etc. [Means for solving the problem]

[0007] One aspect of the present disclosure relates to a reagent for detecting albumin, comprising a terbium complex represented by the following formula (1):

[0008] [ka] (In the formula, R 1 represents an alkyl group having 1 to 3 carbon atoms, and R 2 represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

[0009] Another aspect of the present disclosure relates to a method for detecting albumin in a sample, using a terbium complex represented by the above formula (1). [Effects of the Invention]

[0010] According to one aspect of the present disclosure, a reagent for detecting albumin can be provided. Also, according to another aspect of the present disclosure, a method for detecting albumin in a sample, an albumin detection device, etc. can be provided. [Brief explanation of the drawings]

[0011] [Figure 1A] FIG. 1 shows an example of an FTIR spectrum of a terbium complex according to the present disclosure. [Figure 1B] FIG. 1 shows an example of an FTIR spectrum of a terbium complex according to the present disclosure. [Figure 2] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 3] 1 is an example of a photograph confirming the fluorescence of a reaction product of a terbium complex according to the present disclosure and albumin. [Figure 4] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 5] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 6] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 7] 1 is an example of a photograph confirming the fluorescence of a reaction product of a terbium complex according to the present disclosure and albumin. [Figure 8] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 9] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 10] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 11] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 12] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 13] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 14] 1 is an example of a photograph confirming the fluorescence of a reaction product of a terbium complex according to the present disclosure and albumin. [Figure 15] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 16] 1 is an example of a photograph confirming the fluorescence of a reaction product of a terbium complex according to the present disclosure and albumin. [Figure 17] FIG. 1 is a diagram showing an example of a comparison between the fluorescence spectrum curve of a reaction product of a terbium complex according to the present disclosure and albumin and the fluorescence spectrum curve of the terbium complex alone. [Figure 18] 1 is an example of a photograph confirming the fluorescence of a reaction product of a terbium complex according to the present disclosure and albumin. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments for carrying out the present disclosure will be described, but the embodiments of the present disclosure are not limited to the following embodiments.

[0013] <Reagents for detecting albumin> The reagent for detecting albumin of the present disclosure (also simply referred to as "reagent") contains a terbium complex represented by the following formula (1) (also simply referred to as "terbium complex" or "terbium complex of formula (1)").

[0014] [ka] (In formula (1), R 1 represents an alkyl group having 1 to 3 carbon atoms, and R 2 represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

[0015] In formula (1), R 1 is an alkyl group having 1 to 3 carbon atoms, and is preferably a methyl group, an ethyl group, a propyl group, or an isopropyl group.

[0016] In formula (1), R 2 represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group. 2 If is not a hydrogen atom, R 2 The bonding position of to the benzene ring is not limited, but it is preferably bonded to, for example, the 4-position.

[0017] Examples of the terbium complex of formula (1) include terbium complexes Tb-1 to Tb-7 synthesized in the following Synthesis Examples 1 to 7. In one aspect, although not limited thereto, terbium complex Tb-1 (a terbium complex synthesized using methyl salicylate as a starting material) and terbium complex Tb-5 (a terbium complex synthesized using ethyl salicylate as a starting material) are particularly suitable for detecting albumin.

[0018] In this disclosure, the term "reagent" is defined as a chemical substance used to detect or quantify a substance by chemical methods, to conduct synthetic experiments on a substance, or to measure a physical property. The reagents of this disclosure may contain one terbium complex alone or two or more terbium complexes in combination.

[0019] The reagent of the present disclosure may contain a solvent in addition to the terbium complex of formula (1). The solvent is not limited, but is preferably an organic solvent capable of dissolving the terbium complex, such as dimethyl sulfoxide, methanol, ethanol, N,N-dimethylformamide, tetrahydrofuran, acetone, acetonitrile, 1,4-dioxane, etc. The solvent may be one type or a mixture of two or more types.

[0020] In one embodiment, the reagent of the present disclosure may further contain, in addition to the terbium complex of formula (1), at least one additive selected from a glycol-based compound and glycerol (also referred to as a "glycol-based compound, etc."). The addition of a glycol-based compound, etc., facilitates the reaction between the terbium complex in the reagent and albumin in the sample. Examples of glycol-based compounds include ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol. The content of the glycol-based compound, etc., in the reagent may be 0% by volume relative to the total volume of the solvent, but may preferably be 3% by volume or more, 5% by volume or more, 10% by volume or more, 15% by volume or more, or 20% by volume or more, or may be 50% by volume or less, 40% by volume or less, 30% by volume or less, or 25% by volume or less.

[0021] In one embodiment, when a terbium complex is incorporated into a solid medium such as filter paper (e.g., when producing a test paper), it is preferable to use a reagent containing a glycol-based compound or the like. When a test paper is produced using a reagent containing a glycol-based compound or the like, the glycol-based compound or the like is impregnated into the test paper. If a test paper such as filter paper is impregnated with a water-soluble glycol-based compound and / or glycerol in this way, when albumin is detected using a test paper or the like impregnated with a receptor (terbium complex), the sample of an albumin-containing aqueous solution is more likely to impregnate the filter paper, facilitating a reaction between the receptor and albumin.

[0022] When a solution of the terbium complex of Formula (1) dissolved in a solvent is used as a reagent, the concentration of the terbium complex of Formula (1) in the solution (concentration before mixing with a sample) is not limited, but may be, for example, preferably 0.1 mM or more, 0.2 mM or more, 0.5 mM or more, 1.0 mM or more, 1.5 mM or more, or 2.0 mM or more, and the upper limit may be preferably 10.0 mM or less, 8.0 mM or less, 6.0 mM or less, or 5.0 mM or less. In this specification, the concentration unit "M" means "mol / L." In one embodiment, when the terbium complex of Formula (1) is contained in a test paper and used as a reagent, the test paper containing the terbium complex may be obtained by impregnating a test paper (e.g., filter paper) with the solution of the terbium complex and then drying it at a temperature of room temperature to 80°C.

[0023] One aspect of the present disclosure relates to a terbium complex represented by formula (1), preferably a terbium complex represented by formula (1) for detecting albumin. Another aspect of the present disclosure relates to an albumin detection kit comprising the terbium complex represented by formula (1). Another aspect of the present disclosure relates to an albumin detection kit comprising the above reagent.

[0024] The reagent for detecting albumin of the present disclosure contains a terbium complex of formula (1), and when measuring the fluorescence intensity at a specific wavelength, the intensity of the fluorescence emitted by a mixture of the terbium complex and albumin (also referred to as the "reactant") is greater than the fluorescence intensity of the terbium complex alone, thereby enabling the detection of albumin in a sample.

[0025] In the present disclosure, albumin may be, but is not limited to, for example, human serum albumin (HSA), bovine serum albumin (BSA), etc.

[0026] (Method of producing terbium complex) The terbium complex of formula (1) can be synthesized, for example, by reacting a compound represented by the following formula (21) with terbium chloride hexahydrate in water.

[0027] [ka] (In formula (21), R 1 represents an alkyl group having 1 to 3 carbon atoms, and R 2 represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

[0028] The compound represented by formula (21) can be obtained, for example, by reacting a compound having a corresponding salicylic acid ester skeleton with sodium hydroxide.

[0029] For example, in formula (1), R 1 is a methyl group, R 2 When synthesizing a terbium complex in which is a hydrogen atom, methyl salicylate and sodium hydroxide are reacted to synthesize the sodium salt of methyl salicylate (a compound corresponding to formula (21)), and then this sodium salt of methyl salicylate is reacted with terbium chloride hexahydrate in water to obtain the desired terbium complex.

[0030] <Method for detecting albumin in a sample> In one embodiment of the present disclosure, a method for detecting albumin in a sample includes detecting the fluorescence of a mixture of a terbium complex represented by formula (1) and albumin. In a preferred embodiment, the method for detecting albumin in a sample includes (i) obtaining a mixture of a sample and a reagent containing the terbium complex represented by formula (1) (step (i)), (ii) irradiating the mixture with excitation light of a specific wavelength (step (ii)), and (iii) detecting the fluorescence emitted from the mixture (step (iii)). Step (i) is preferably performed in water. The method for detecting albumin of the present disclosure utilizes the phenomenon in which the interaction between the terbium complex represented by formula (1) and albumin increases fluorescence when they are mixed and brought into contact. That is, while the terbium complex alone hardly emits fluorescence in aqueous solution, the mixture (reactant) obtained by the reaction of the terbium complex with albumin emits additional fluorescence. Utilizing this phenomenon makes it possible to detect albumin in a sample. Furthermore, even when a sample contains ions (sodium ions, potassium ions, calcium ions, etc.) and nitrogen compounds (urea, sodium urate, creatinine, etc.) commonly present in urine, mixing with the terbium complex represented by formula (1) produces little or no fluorescence in the absence of albumin. On the other hand, even when the sample contains the above ions and nitrogen compounds, in the presence of albumin, they react with the terbium complex and produce significant fluorescence. Therefore, the terbium complex represented by formula (1) is effective for detecting albumin in urine.

[0031] Conventional methods for detecting albumin include urine test strips and turbidimetric immunoassays (TIA). However, while known urine test strips can detect albumin inexpensively and easily, they may lack sufficient sensitivity, failing to detect advanced histological changes in the kidneys, such as in diabetic nephropathy. Furthermore, while TIA methods for detecting albumin tend to be highly sensitive, they are expensive and require complex detection procedures. Therefore, there has been a need for the development of a reagent for detecting albumin in a sample that is simple and inexpensive to use and that can detect albumin with high sensitivity even at low albumin concentrations.

[0032] The albumin detection method of the present disclosure can be performed inexpensively and simply, and can detect albumin with high sensitivity even when the albumin concentration in a sample is low. Therefore, the albumin detection method of the present disclosure is considered to be useful for early detection, prevention, slowing of progression, treatment, etc. of diabetic nephropathy and other conditions in which the amount of albumin in urine increases.

[0033] In one embodiment of the present disclosure, the sample is preferably, but not limited to, a biological sample, such as blood, plasma, serum, lymph, saliva, sweat, tears, urine, etc., and in one embodiment, urine is preferred. The biological sample is preferably, but not limited to, derived from a mammal, such as a human, cow, goat, sheep, pig, monkey, dog, cat, rat, mouse, hamster, guinea pig, etc., and more preferably a human. The sample may be a solid or a solution. The solution may be a body fluid, may contain a solvent other than a body fluid, or may be a mixture thereof. Furthermore, the collected sample may be used as is, or may be a solution obtained by diluting or concentrating the collected sample with water or the like. In one embodiment, the solution may be a solution used for sample measurement, a solution used for calibration measurement, a standard solution, or a calibration solution.

[0034] The mixing (contact) of the sample with the reagent in step (i) is preferably carried out under conditions that allow the reaction of albumin with the terbium complex when albumin is present in the sample, more preferably in a solution, and even more preferably in an aqueous solution. In one embodiment, a solution containing the terbium complex of formula (1) is mixed with the sample (preferably containing water), stirred as necessary, and reacted at room temperature (about 5 to 40°C, preferably about 15 to 35°C) for 30 seconds or more, preferably 1 minute or more (for example, 1 minute to 120 minutes, preferably 1 minute to 60 minutes).

[0035] The mixing ratio of the reagent containing the terbium complex to the sample is not limited and can be appropriately adjusted depending on the type of terbium complex used, the albumin concentration in the sample, etc. In one embodiment, for example, the terbium complex is preferably mixed at 1x10 -6 mol or more, more preferably 1x10 -5 It is preferable to mix them so that the volume is 1 / 2 mol or more. In one embodiment, although not limited thereto, when mixing the sample and the reagent in step (i), the volume of the sample (aqueous solution) may be, for example, 30 times or more, 50 times or more, or 80 times or more, or 500 times or less, 300 times or less, or 200 times or less, the volume of the solution (reagent) containing the terbium complex. In one embodiment, for example, the ratio of {volume of the reagent containing the terbium complex (preferably a 0.1 mM to 10 mM solution)}:{volume of the sample (aqueous solution)}} may be 1:30 to 1:200, preferably 1:80 to 1:150.

[0036] In one embodiment, the reaction between a reagent containing the terbium complex of formula (1) and a sample may be carried out in a solid medium containing the reagent. Examples of solid media include, but are not limited to, paper (e.g., filter paper), glass (e.g., glass fiber, porous glass substrate, etc.), resin (e.g., polymethyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, polystyrene, nylon resin, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide), and water-soluble polymers (cellulose-based, agarose, starch-based, sodium alginate, acrylic acid-based, acrylamide-based, polyvinyl alcohol, polyethylene oxide, polyvinylpyrrolidone, etc.). One embodiment of the method for detecting albumin in a solid medium is, for example, a method using a test paper containing a terbium complex. The test paper containing the terbium complex can be obtained, for example, by impregnating paper such as filter paper with a solution of the terbium complex and then drying it. The conditions for impregnating a paper such as filter paper with a solution of a terbium complex and then drying the paper are not limited, but for example, the temperature is preferably room temperature (15°C to 30°C) or higher, more preferably 40°C or higher, even more preferably 50°C or higher, and preferably 80°C or lower. Furthermore, although not limited, the relative humidity during drying is preferably 15%RH to 60%RH, and the ambient pressure is preferably standard atmospheric pressure (1013.25 hPa) or lower. The drying time is not limited and may be, for example, 1 hour or longer. In one embodiment, the solution of the terbium complex impregnated into paper such as filter paper preferably contains at least one compound selected from the group consisting of the glycol compounds and glycerol described above. When the paper such as filter paper contains a water-soluble glycol compound and / or glycerol, the aqueous solution of the sample (aqueous albumin solution) can more easily impregnate the filter paper, facilitating the reaction between the terbium complex and albumin.

[0037] One embodiment of the method for detecting albumin in a solid medium includes a step of immersing a test paper containing a terbium complex in an aqueous solution of a sample containing albumin to cause a reaction, and a step of detecting fluorescence emitted by the reaction product of the terbium complex and albumin. Another embodiment of the method for detecting albumin in a solid medium includes a step of dropping an aqueous solution of a sample containing albumin onto a test paper containing a terbium complex to cause a reaction, and a step of detecting fluorescence emitted by the reaction product of the terbium complex and albumin.

[0038] In step (ii), the mixture obtained in step (i) is irradiated with excitation light. The wavelength of the irradiated excitation light is not limited, but is preferably 200 to 500 nm, more preferably 300 to 400 nm, for example.

[0039] In step (iii), albumin can be detected by utilizing the phenomenon that the terbium complex alone shows almost no fluorescence, whereas the reaction product of the terbium complex and albumin newly emits fluorescence. In one embodiment, a step of determining the albumin concentration by comparing the detected fluorescence intensity with a predetermined reference value can also be performed. In one embodiment, the albumin concentration in a sample can be determined from images of the fluorescence emitted by the reaction product of the sample and the terbium complex. Specifically, first, a plurality of albumin solutions with known but different concentrations are reacted with a terbium complex, and the reaction product is irradiated with excitation light to capture images of the luminescence state, which are then acquired in advance as reference image data. Next, a sample of unknown concentration is reacted with a terbium complex, and the luminescence state of the reaction product is captured in the same manner as the reference image data to obtain image data of the sample. The albumin concentration can then be determined by comparing the obtained image data of the sample with the reference image data. By incorporating such an image data collation system into a smartphone, it is possible to acquire luminescence image data of a sample, compare the sample image data with reference image data, and determine the albumin concentration in the sample using a single smartphone. Note that, from the viewpoint of accurately capturing the intensity of the luminescence image, it is preferable to capture the luminescence image in a state where no external light enters, for example, in the absence of external lighting.

[0040] The terbium complex of formula (1) of the present disclosure can detect albumin with high sensitivity even when the albumin concentration in a sample is low. The albumin concentration in the sample may be, for example, 0.0001 mg / mL or more, 0.0005 mg / mL or more, 0.001 mg / mL or more, or 0.01 mg / mL or more, and may be, for example, 100 mg / mL or less, 50 mg / mL or less, 10 mg / mL or less, 5 mg / mL or less, or 3 mg / mL or less. The terbium complex of the present disclosure can detect the presence of albumin with high sensitivity even when the albumin concentration in the sample is low (for example, less than 0.3 mg / mL, less than 0.1 mg / mL, less than 0.01 mg / mL, or less than 0.01 mg / mL).

[0041] <Albumin detection device> One aspect of the present disclosure relates to an albumin detection device (also simply referred to as a "detection device" or "albumin detection device") having a reagent containing a terbium complex represented by formula (1). In one aspect, the albumin detection device includes an albumin capture unit having a reagent containing a terbium complex represented by formula (1), and a detection unit that detects that albumin has been captured by the capture unit.

[0042] (Capture part) The capture unit of the albumin detection device of the present disclosure has a reagent containing a terbium complex of formula (1). The above description of the reagent for detecting albumin applies to the reagent. In one embodiment, the reagent preferably contains a solvent (preferably an organic solvent) and is a solution in which the terbium complex of formula (1) is dissolved. In one embodiment, the sample and the reagent may be mixed in the capture unit.

[0043] (Detection unit) The detection unit of the albumin detection device is preferably configured to optically detect that albumin has been captured by the capture unit. The detection unit may be configured as a separate device rather than being integrated with the capture unit. In one aspect, the optical detection unit includes an excitation light source (light emitter) and a detection element (fluorescence receiver) to detect the fluorescence emission of the reaction product of the terbium complex of formula (1) and albumin, and can detect and / or measure the concentration of albumin based on the observed change in fluorescence intensity.

[0044] In one embodiment, the detection unit may include a computer that executes a program for processing the detection and / or concentration measurement of albumin. Such a program may be, for example, a program that causes the computer to execute the steps of: (i) receiving a signal from an optical detection element; (ii) analyzing the received signal to determine the presence or absence and / or concentration of albumin; and (iii) outputting the analysis results.

[0045] In one embodiment of the present disclosure, analyzing the received signal may include, for example, determining the presence and / or concentration of albumin by comparing the received signal with a predetermined reference value. Also, in one embodiment of the present disclosure, the analysis results may be output, for example, to a display device connected to the sensor (detection device) or to another device connected via a network. [Example]

[0046] The present disclosure will be explained in more detail below by way of examples, but the present disclosure is not limited to these examples.

[0047] (Synthesis Example 1: Synthesis of terbium complex (Tb-1) represented by the following formula) [ka]

[0048] 2.254 g of methyl salicylate was dissolved in 5 ml of acetone, and 0.595 g of sodium hydroxide dissolved in 10 ml of water was added and stirred overnight at room temperature. The solvent was evaporated under reduced pressure, and the mixture was dried under reduced pressure to obtain 2.265 g of the sodium salt of methyl salicylate. Next, 0.4632 g of the sodium salt of methyl salicylate was dissolved in 20 ml of water, and 0.3 g of terbium chloride hexahydrate dissolved in 20 ml of water was added to the mixture and stirred overnight at room temperature. The precipitated terbium complex was filtered, washed with water, and then dried under reduced pressure to obtain 0.399 g of the desired white terbium complex Tb-1.

[0049] Elemental analysis of the obtained terbium complex revealed that it contained 46.6% carbon (theoretical value: 47.1%) and 3.2% hydrogen (theoretical value: 3.5%).

[0050] The FTIR spectrum of Tb-1 was also measured. The obtained FTIR spectrum is shown in Figures 1A and 1B. The characteristic absorption of the OH group of the raw material methyl salicylate (3000-3300) was observed. -1 ) disappears (Figure 1B), and the characteristic absorption of C=O is observed at 1673 cm for methyl salicylate.-1 In contrast, Tb-1 is 1660 cm -1 The characteristic absorption of Ph-O is shifted to the lower frequency side (Fig. 1A). Furthermore, the characteristic absorption of Ph-O is shifted to 1251 cm for methyl salicylate. -1 In contrast, Tb-1 is 1227 cm -1 The vibrational frequency shifts to the lower frequency side (Fig. 1A). This indicates that the structural formula is Tb-1, in which a carbonyl group and a Ph-O group are coordinated to terbium.

[0051] (Synthesis Example 2: Synthesis of terbium complex (Tb-2) represented by the following formula) [ka]

[0052] Terbium complex Tb-2 was synthesized in the same manner as in Synthesis Example 1, except that methyl 4-methoxysalicylate was used instead of methyl salicylate. The FTIR spectrum of Tb-2 was measured. The characteristic absorption of C=O was observed at 1660 cm for methyl 4-methoxysalicylate. -1 whereas in Tb-2 it is 1632 cm -1 Furthermore, the characteristic absorption of Ph-O was shifted to the lower frequency side at 1247 cm for methyl 4-methoxysalicylate. -1 whereas in Tb-2 it is 1234 cm -1 This indicates that the structural formula is Tb-2, in which a carbonyl group and a Ph-O group are coordinated to terbium.

[0053] (Synthesis Example 3: Synthesis of terbium complex (Tb-3) represented by the following formula) [ka]

[0054] Terbium complex Tb-3 was synthesized in the same manner as in Synthesis Example 1, except that methyl 4-methylsalicylate was used instead of methyl salicylate. The FTIR spectrum of Tb-3 was measured. The characteristic absorption of C=O was observed at 1660 cm for methyl 4-methylsalicylate.-1 whereas in Tb-3 it is 1633 cm -1 The characteristic absorption of Ph-O was also shifted to the lower frequency side at 1247 cm for methyl 4-methylsalicylate. -1 whereas for Tb-3 it is 1234 cm -1 This indicates that the structure is Tb-3, in which a carbonyl group and a Ph-O group are coordinated to terbium.

[0055] (Synthesis Example 4: Synthesis of terbium complex (Tb-4) represented by the following formula) [ka]

[0056] Terbium complex Tb-4 was synthesized in the same manner as in Synthesis Example 1, except that methyl 4-fluorosalicylate was used instead of methyl salicylate. The FTIR spectrum of Tb-4 was measured. The characteristic absorption of C=O was observed at 1665 cm for methyl 4-fluorosalicylate. -1 In contrast, Tb-4 was 1640 cm -1 The characteristic absorption of Ph-O was also shifted to the lower frequency side at 1258 cm for methyl 4-fluorosalicylate. -1 In contrast, Tb-4 was 1227 cm -1 This indicates that the structure is Tb-4, in which a carbonyl group and a Ph-O group are coordinated to terbium.

[0057] (Synthesis Example 5: Synthesis of terbium complex (Tb-5) represented by the following formula) [ka]

[0058] Terbium complex Tb-5 was synthesized in the same manner as in Synthesis Example 1, except that ethyl salicylate was used instead of methyl salicylate (where Et represents an ethyl group). The FTIR spectrum of Tb-5 was measured. The characteristic absorption of C=O was observed at 1671 cm for ethyl salicylate.-1 whereas Tb-5 has a peak of 1658 cm -1 The characteristic absorption of Ph-O was also shifted to the low frequency side at 1248 cm for ethyl salicylate. -1 whereas Tb-5 is 1225 cm -1 This indicates that the structure is Tb-5, in which a carbonyl group and a Ph-O group are coordinated to terbium.

[0059] (Synthesis Example 6: Synthesis of terbium complex (Tb-6) represented by the following formula) [ka]

[0060] Terbium complex Tb-6 was synthesized in the same manner as in Synthesis Example 1, except that isopropyl salicylate was used instead of methyl salicylate. The FTIR spectrum of Tb-6 was measured. The characteristic absorption of C=O was observed at 1664 cm for isopropyl salicylate. -1 whereas for Tb-6 it is 1656 cm -1 The characteristic absorption of Ph-O was also shifted to the low frequency side at 1250 cm for isopropyl salicylate. -1 On the other hand, Tb-6 is 1227 cm -1 This indicates that the structure is Tb-6, in which a carbonyl group and a Ph-O group are coordinated to terbium.

[0061] (Synthesis Example 7: Synthesis of terbium complex (Tb-7) represented by the following formula) [ka]

[0062] Terbium complex Tb-7 was synthesized in the same manner as in Synthesis Example 1, except that methyl 4-hydroxysalicylate was used instead of methyl salicylate. The FTIR spectrum of Tb-7 was measured. The characteristic absorption of C=O was observed at 1636 cm for methyl 4-hydroxysalicylate. -1In contrast, Tb-7 was 1628 cm -1 The characteristic absorption of Ph-O was also shifted to the lower frequency side at 1264 cm for methyl 4-hydroxysalicylate. -1 On the other hand, Tb-7 is 1254 cm -1 This indicates that the structure is Tb-7, in which a carbonyl group and a Ph-O group are coordinated to terbium.

[0063] (Example 1) A dimethyl sulfoxide (DMSO) solution of the terbium complex (Tb-1) obtained in Synthesis Example 1 was prepared (concentration: 5 mM). Furthermore, an aqueous solution of albumin (HSA, derived from human serum, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was prepared (concentration: 1 mg / ml). Next, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of the HSA solution and allowed to stand at room temperature for 1 hour. The mixture was then filtered using a 0.45 μm PTFE filter. 3 mL of the filtrate was placed in a quartz cell, and the fluorescence spectrum was measured at an excitation light of 350 nm. In addition, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of water without HSA, and the fluorescence spectrum was measured in the same manner. The obtained fluorescence spectrum curve is shown in Figure 2. The solid line represents the fluorescence spectrum of Tb-1 + HSA, and the dashed line represents the fluorescence spectrum of Tb-1 alone. The fluorescence intensity of Tb-1 + HSA at a wavelength of 546 nm was 51,200. On the other hand, the fluorescence intensity of Tb-1 alone was 50, indicating that the fluorescence emission intensity increased by approximately 1,000 times. Figure 3 shows photographs of the emission state when the quartz cells containing each solution were excited with a UV lamp at a wavelength of 365 nm. Yellow-green emission was visually confirmed in the solution containing HSA (b). On the other hand, no emission was confirmed in the solution without HSA (a). Furthermore, as shown in Figure 3, we found that the presence of HSA can be confirmed by photographing the luminescence state of the reaction product of a terbium complex and HSA using a smartphone or other device. Furthermore, as described below, the concentration of HSA in a sample can be determined from image data of the luminescence state of the reaction product of a terbium complex and HSA. First, a terbium complex is reacted with each of several HSA solutions of known and varying concentrations. The reaction product is irradiated with excitation light, and the resulting luminescence images are captured and used as reference image data. Next, a sample of unknown concentration is reacted with a terbium complex, and the luminescence state of the reaction product is captured in the same manner as the reference image data to obtain sample image data. The HSA concentration can then be determined by comparing the resulting sample image data with the reference image data. By incorporating such an image data collation system into a smartphone, luminescence image data of the sample can be acquired and subsequently compared with the reference image data, thereby determining the HSA concentration in the sample. Note that, in order to accurately capture the intensity of the luminescence image, it is preferable to capture the luminescence images in a state where external light, for example, no external illumination, is present.

[0064] (Example 2, Example 3) Evaluation was performed in the same manner as in Example 1, except that the terbium complex (Tb-1) obtained in Synthesis Example 1 was replaced with the terbium complexes (Tb-2 and Tb-3) obtained in Synthesis Examples 2 and 3, respectively. The fluorescence intensity at 546 nm of the obtained fluorescence spectrum is shown in Table 1. These results demonstrate that the emission intensity of the terbium complexes (Tb-2 and Tb-3) increases in the presence of HSA. Note that "au" represents an arbitrary unit.

[0065] [Table 1]

[0066] (Example 4) A dimethyl sulfoxide (DMSO) solution of the terbium complex (Tb-1) obtained in Synthesis Example 1 was prepared (concentration: 2.5 mM). Furthermore, an aqueous solution of albumin (HSA, derived from human serum, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was also prepared (concentration: 0.1 mg / ml). Next, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of the HSA solution and allowed to stand at room temperature for 1 hour. After that, 3 mL of the mixed solution was placed in a quartz cell, and the fluorescence spectrum was measured at an excitation light of 350 nm. In addition, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of water without HSA, and the fluorescence spectrum was measured in the same manner. The obtained fluorescence spectrum curves are shown in Figure 4. The solid line represents the fluorescence spectrum of Tb-1 + HSA, and the dashed line represents the fluorescence spectrum of Tb-1 alone. The fluorescence intensity of Tb-1 + HSA at a wavelength of 546 nm was found to be approximately 50-fold greater than that of Tb-1 alone.

[0067] (Example 5) A dimethyl sulfoxide (DMSO) solution of the terbium complex (Tb-1) obtained in Synthesis Example 1 was prepared (concentration: 2.5 mM). Furthermore, an aqueous solution of albumin (HSA, derived from human serum, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was also prepared (concentration: 0.01 mg / ml). Next, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of the HSA solution and allowed to stand at room temperature for 1 hour. After that, 3 mL of the mixed solution was placed in a quartz cell, and the fluorescence spectrum was measured at an excitation light of 350 nm. Furthermore, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of water without HSA, and the fluorescence spectrum was measured in the same manner. The obtained fluorescence spectrum curves are shown in Figure 5. The solid line represents the fluorescence spectrum of Tb-1 + HSA, and the dashed line represents the fluorescence spectrum of Tb-1 alone. The fluorescence intensity of Tb-1 + HSA at a wavelength of 546 nm was found to be approximately 46-fold greater than that of Tb-1 alone.

[0068] (Example 6) A dimethyl sulfoxide (DMSO) solution of the terbium complex (Tb-4) obtained in Synthesis Example 4 was prepared (concentration: 0.25 mM). Furthermore, an aqueous solution of albumin (HSA, derived from human serum, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was also prepared (concentration: 0.01 mg / ml). Next, 40 μL of a DMSO solution of Tb-4 was added to 4 mL of the HSA solution and allowed to stand at room temperature for 1 hour. After that, 3 mL of the mixed solution was placed in a quartz cell, and the fluorescence spectrum was measured at an excitation light of 350 nm. Similarly, 40 μL of a DMSO solution of Tb-4 was added to 4 mL of water without HSA, and the fluorescence spectrum was measured in the same manner. The obtained fluorescence spectrum curves are shown in Figure 6. The solid line represents the fluorescence spectrum of Tb-4 + HSA, and the dashed line represents the fluorescence spectrum of Tb-4 alone. The fluorescence intensity of Tb-4 + HSA at a wavelength of 546 nm was found to be approximately 70-fold greater than that of Tb-4 alone. Figure 7 shows photographs of the luminescence observed when the quartz cells containing each solution were excited with a UV lamp at a wavelength of 365 nm. Yellow-green luminescence was visible in the solution containing HSA (b), whereas no luminescence was observed in the solution without HSA (a).

[0069] (Example 7) A dimethyl sulfoxide (DMSO) solution of the terbium complex (Tb-1) obtained in Synthesis Example 1 was prepared (concentration: 2.5 mM). Furthermore, an aqueous solution of albumin (HSA, derived from human serum, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was prepared (concentration: 0.001 mg / ml). Next, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of the HSA solution and allowed to stand at room temperature for 1 hour. After that, 3 mL of the mixed solution was placed in a quartz cell, and the fluorescence spectrum was measured at an excitation light of 350 nm. Similarly, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of water without HSA, and the fluorescence spectrum was measured in the same manner. The obtained fluorescence spectrum curves are shown in Figure 8. The solid line represents the fluorescence spectrum of Tb-1 + HSA, and the dashed line represents the fluorescence spectrum of Tb-1 alone. The fluorescence intensity of Tb-1 + HSA at a wavelength of 546 nm was found to be approximately 8-fold higher than that of Tb-1 alone.

[0070] (Example 8) A dimethyl sulfoxide (DMSO) solution of the terbium complex (Tb-5) obtained in Synthesis Example 5 was prepared (concentration: 2.5 mM). Furthermore, an aqueous solution of albumin (HSA, derived from human serum, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was prepared (concentration: 0.01 mg / ml). Next, 40 μL of a DMSO solution of Tb-5 was added to 4 mL of the HSA solution and allowed to stand at room temperature for 1 hour. After that, 3 mL of the mixed solution was placed in a quartz cell, and the fluorescence spectrum was measured at an excitation light of 350 nm. Similarly, 40 μL of a DMSO solution of Tb-5 was added to 4 mL of water without HSA, and the fluorescence spectrum was measured in the same manner. The obtained fluorescence spectrum curves are shown in Figure 9. The solid line represents the fluorescence spectrum of Tb-5 + HSA, and the dashed line represents the fluorescence spectrum of Tb-5 alone. The fluorescence intensity of the Tb-5 + HSA solution at a wavelength of 546 nm was found to be approximately 20-fold greater than that of Tb-5 alone.

[0071] (Example 9) A dimethyl sulfoxide (DMSO) solution of the terbium complex (Tb-1) obtained in Synthesis Example 1 was prepared (concentration: 0.5 mM). Furthermore, an aqueous solution of albumin (HSA, derived from human serum, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was also prepared (concentration: 0.01 mg / ml). Next, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of the HSA solution and allowed to stand at room temperature for 1 minute. Then, 3 mL of the mixed solution was placed in a quartz cell, and the fluorescence spectrum was measured at an excitation light of 350 nm. In addition, 40 μL of a DMSO solution of Tb-1 was added to 4 mL of water without HSA, and the fluorescence spectrum was measured in the same manner. The obtained fluorescence spectrum curves are shown in Figure 10. The solid line represents the fluorescence spectrum of Tb-1 + HSA, and the dashed line represents the fluorescence spectrum of Tb-1 alone. The fluorescence intensity of Tb-1 + HSA at a wavelength of 546 nm was found to be approximately 60-fold greater than that of Tb-1 alone.

[0072] (Example 10) Evaluation was performed in the same manner as in Example 9, except that the excitation light was changed from 350 nm to 365 nm. The obtained fluorescence spectrum curve is shown in Figure 11. The solid line represents the fluorescence spectrum of Tb-1 + HSA, and the dashed line represents the fluorescence spectrum of Tb-1 alone. The obtained fluorescence spectrum showed that the fluorescence intensity of Tb-1 + HSA at a wavelength of 546 nm was approximately 90 times greater than that of Tb-1 alone.

[0073] (Example 11) <Detection of HSA in an aqueous solution containing various ions (sodium ions, potassium ions, calcium ions) and nitrogen compounds (urea, sodium urate, creatinine) present in urine> An aqueous solution (11a) containing various ions and nitrogen compounds was prepared by dissolving 4.2 ml of 1 M sodium chloride solution, 0.12 ml of 1 M potassium chloride solution, 0.69 ml of 0.1 M calcium chloride solution, 6 mg of urea, 0.3 mg of creatinine, and 1.7 mg of sodium urate in 24.99 ml of water. Next, an aqueous solution (11a) containing albumin (HSA, derived from human serum, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (HSA aqueous solution (11b)) was prepared using this aqueous solution (11a) (concentration: 0.01 mg / ml). Next, a dimethyl sulfoxide (DMSO) solution of the terbium complex (Tb-1) obtained in Synthesis Example 1 was prepared (concentration: 0.5 mM). Next, the HSA aqueous solution (11b) was placed in a 3 ml quartz cell, and 30 μL of the DMSO solution of Tb-1 was added. The solution was then left at room temperature for 2 minutes. The fluorescence spectrum was then measured at an excitation light of 365 nm. In addition, 30 μL of a DMSO solution of Tb-1 was added to 3 mL of an aqueous solution (aqueous solution (11a)) that did not contain HSA, and the fluorescence spectrum was measured in the same manner. The obtained fluorescence spectrum curve is shown in Figure 12. The solid line represents the fluorescence spectrum of Tb-1 + HSA, and the dashed line represents the fluorescence spectrum of Tb-1 alone. The fluorescence intensity of Tb-1 + HSA at a wavelength of 546 nm obtained in the fluorescence spectrum was 3906. On the other hand, the fluorescence intensity of Tb-1 alone was 14. Thus, even in a solution containing various ions and nitrogen compounds commonly present in urine, the presence of HSA increased the fluorescence emission intensity by approximately 279-fold, demonstrating that HSA could be detected by fluorescence.

[0074] (Example 12) <Detection of HSA in an aqueous solution containing various ions (sodium ions, potassium ions, calcium ions) and nitrogen compounds (urea, sodium urate, creatinine) present in urine> The same procedure as in Example 11 was repeated, except that Tb-5 was used instead of Tb-1. The resulting fluorescence spectrum curves are shown in Figure 13. The solid line represents the fluorescence spectrum of Tb-5 + HSA, and the dashed line represents the fluorescence spectrum of Tb-5 alone. The fluorescence intensity of Tb-5 + HSA at a wavelength of 546 nm was 19981. On the other hand, the fluorescence intensity of Tb-5 alone was 227. Thus, it was found that the presence of HSA increased the fluorescence emission intensity by approximately 88-fold. Figure 14 also shows photographs of the emission state when quartz cells containing each solution were excited with a UV lamp at a wavelength of 365 nm. Yellow-green emission was visually observed in the solution containing HSA (b). On the other hand, almost no emission was observed in the solution without HSA (a).

[0075] (Example 13) <Detection in aqueous solution containing various ions (sodium ions, potassium ions, calcium ions) and nitrogen compounds (urea, sodium urate, creatinine) present in urine> The same procedure as in Example 11 was repeated, except that Tb-4 was used instead of Tb-1. The resulting fluorescence spectrum curves are shown in Figure 15. The solid line represents the fluorescence spectrum of Tb-4 + HSA, and the dashed line represents the fluorescence spectrum of Tb-4 alone. The fluorescence intensity of Tb-4 + HSA at a wavelength of 546 nm was 1610. On the other hand, the fluorescence intensity of Tb-4 alone was 86. This demonstrates that the presence of HSA increases the fluorescence intensity by approximately 19-fold. Figure 16 also shows photographs of the emission state when quartz cells containing each solution were excited with a UV lamp at a wavelength of 365 nm. Yellow-green emission was visually observed in the solution containing HSA (b). On the other hand, almost no emission was observed in the solution without HSA (a).

[0076] (Example 14) <HSA detection using test strips> A 20 mM solution of the terbium complex (Tb-5) obtained in Synthesis Example 5 in a dimethyl sulfoxide (DMSO) / polyethylene glycol 200 (Tokyo Chemical Industry Co., Ltd.) mixture (volume ratio: 80 / 20) was prepared. 0.2 ml of this solution was dripped onto filter paper (40 mm diameter) to impregnate it, and the filter paper was dried at 50 °C and cut into 1 cm widths. An aqueous solution of albumin (HSA, derived from human serum, Fujifilm Wako Pure Chemical Industries, Ltd.) was also prepared (concentration: 0.1 mg / ml). The terbium complex-impregnated filter paper was then immersed in a glass sample container (10 ml capacity) containing 9 ml of HSA solution for 30 seconds, removed, and allowed to stand at room temperature for 5 minutes. The fluorescence spectrum of the resulting filter paper was measured at 350 nm excitation light. The fluorescence spectrum of the terbium complex-impregnated filter paper immersed in 9 ml of water without HSA was also measured. The resulting fluorescence spectrum curve is shown in Figure 17. The solid line represents the fluorescence spectrum of Tb-5 + HSA, and the dashed line represents the fluorescence spectrum of Tb-5 + water alone. The fluorescence spectrum of Tb-5 + water alone does not have an emission peak near 540 nm, but Tb-5 + HSA exhibits a peak of 28,400 nm in fluorescence intensity at 543 nm. Figure 18 also shows photographs of the emission state when each filter paper was excited with a UV lamp at a wavelength of 365 nm. In the filter paper immersed in an aqueous solution containing HSA (b), the yellow-green emission characteristic of terbium complexes was clearly visible in the image. On the other hand, in the filter paper immersed in water alone, which did not contain HSA (a), almost no emission was observed. Thus, in the aqueous solution containing HSA, the presence of HSA can be visually confirmed in the emission image.

[0077] Although the present disclosure has been described above with reference to embodiments and examples, the present disclosure is not limited to the above embodiments and examples. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. Furthermore, each embodiment can be combined with other embodiments as appropriate. This application claims priority based on Japanese Patent Application No. 2024-093705, filed June 10, 2024, and Japanese Patent Application No. 2025-013609, filed January 30, 2025, the disclosures of which are incorporated herein in their entireties.

[0078] Some or all of the above embodiments can be described as in the following supplementary notes, but the disclosure of the present application is not limited to the following supplementary notes.

[0079] (Appendix 1) A reagent for detecting albumin, comprising a terbium complex represented by the following formula (1):

[0080] [ka] (In the formula, R 1 represents an alkyl group having 1 to 3 carbon atoms, and R 2 represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

[0081] (Appendix 2) 2. The reagent of claim 1, further comprising a solvent.

[0082] (Appendix 3) The reagent according to Appendix 1 or 2, further comprising at least one selected from the group consisting of glycol compounds and glycerol.

[0083] (Appendix 4) A method for detecting albumin in a sample using a terbium complex represented by the following formula (1):

[0084] [ka] (In the formula, R 1 represents an alkyl group having 1 to 3 carbon atoms, and R 2 represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

[0085] (Appendix 5) A method for detecting albumin according to Appendix 4, which utilizes the phenomenon in which the fluorescence emission of the terbium complex represented by formula (1) increases upon interaction with albumin.

[0086] (Appendix 6) (i) obtaining a mixture of a reagent containing a terbium complex represented by formula (1) and a sample; (ii) irradiating the mixture with excitation light; and (iii) detecting the fluorescence emitted by the mixture 6. A method for detecting albumin according to claim 4 or 5, comprising:

[0087] (Appendix 7) A terbium complex represented by the following formula (1): [ka] (In the formula, R 1 represents an alkyl group having 1 to 3 carbon atoms, and R 2 represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

[0088] (Appendix 8) 8. A terbium complex according to claim 7, for use in detecting albumin.

[0089] (Appendix 9) A capture part for albumin having the reagent according to any one of Supplementary Notes 1 to 3; a detection unit that detects that albumin has been captured by the capture unit; An albumin detection device comprising:

[0090] (Appendix 10) 10. The albumin detection device according to claim 9, wherein the detection unit detects the fluorescence emitted by a reaction product of the terbium complex represented by formula (1) and albumin.

[0091] (Appendix 11) A test paper for detecting albumin, comprising the reagent according to any one of Appendices 1 to 3.

[0092] (Appendix 12) a terbium complex represented by the formula (1); At least one selected from the group consisting of glycol compounds and glycerol; 1. A test paper for detecting albumin, comprising:

[0093] (Appendix 13) A kit for detecting albumin, comprising the reagent according to any one of Appendices 1 to 3.

[0094] (Appendix 14) An albumin detection system comprising: acquiring reference image data in advance that shows the fluorescence emission of a reaction product of the terbium complex described in Appendix 7 or 8 with albumin of a known concentration; and comparing image data that shows the fluorescence emission of a reaction product of the terbium complex described in Appendix 7 or 8 with a sample, to determine the concentration of albumin in the sample.

Claims

1. A reagent for detecting albumin, comprising a terbium complex represented by the following formula (1): 【Chemistry 1】 (In the formula, R １ represents an alkyl group having 1 to 3 carbon atoms, and R ２ represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

2. The reagent of claim 1 , further comprising a solvent.

3. The reagent according to claim 1 or 2, further comprising at least one selected from the group consisting of glycol compounds and glycerol.

4. A method for detecting albumin in a sample using a terbium complex represented by the following formula (1): 【Chemistry 2】 (In the formula, R １ represents an alkyl group having 1 to 3 carbon atoms, and R ２ represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

5. 5. The method for detecting albumin according to claim 4, which utilizes the phenomenon that the fluorescence emission of the terbium complex represented by formula (1) increases upon interaction with albumin.

6. (i) obtaining a mixture of a reagent containing a terbium complex represented by formula (1) and a sample; (ii) irradiating the mixture with excitation light; and (iii) detecting the fluorescence emitted from the mixture 6. A method for detecting albumin according to claim 4 or 5, comprising:

7. A terbium complex represented by the following formula (1): 【Transformation 3】 (In the formula, R １ represents an alkyl group having 1 to 3 carbon atoms, and R ２ represents a hydrogen atom, a methyl group, a methoxy group, a fluorine atom, or a hydroxy group.

8. 8. The terbium complex of claim 7, which is used to detect albumin.

9. A capture part for albumin having the reagent according to claim 1 or 2; a detection unit that detects the capture of albumin by detecting the fluorescence emitted by a reaction product of the terbium complex represented by formula (1) and albumin; and An albumin detection device comprising:

10. A test paper for detecting albumin, comprising the reagent according to claim 1 or 2.

11. An albumin detection system which obtains reference image data in advance that shows the fluorescence emission of a reaction product of the terbium complex described in claim 7 with albumin of a known concentration, and compares the image data that shows the fluorescence emission of the reaction product of the terbium complex described in claim 7 with a sample with the reference image data to determine the concentration of albumin in the sample.

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