JP2009281906A - Method, device and instrument for measuring creatinine, and method, device and instrument for measuring amount of salt in urine using those means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, device and instrument capable of performing the precise quantification of creatinine contained in a sample. <P>SOLUTION: The creatinine measuring method includes step (A) for bringing the sample containing creatinine into contact with a creatinine measuring reagent containing a quinone compound to directly react creatine contained in the sample with the quinone component to thereby produce the reduced substance of the quinone compound, step (B) for optically measuring the reaction in the step A, and step (C) for determining the concentration or amount of creatinine contained in the sample on the basis of the measured value in the step B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a measurement method, a measurement device, and a measurement apparatus for quantifying creatinine and salt contained in a sample.

  Measurement of creatinine contained in a sample is important in the fields of clinical chemistry and analytical chemistry. Since creatinine is a product of the endogenous metabolism of muscle, it is known that the amount of creatinine in urine reflects the total muscle mass. Therefore, it is said that the amount of creatinine in urine excreted by humans in a day is generally constant for each individual and does not vary from day to day. Therefore, the amount of creatinine in urine is sometimes used as a measure of the density of excreted urine. Moreover, since the amount of creatinine in urine and blood increases or decreases due to uremia or a decrease in renal function, the presence or absence of uremia or a decrease in kidney function can be known by measuring the amount of creatinine in urine or blood.

  As a method for measuring creatinine, a method based on a Jaffe reaction using an alkaline picric acid solution is known. In this method, an orange-red product obtained by reacting picric acid with creatinine is measured spectroscopically (see, for example, Patent Document 1).

  As another creatinine measurement method, a method using an enzyme that specifically reacts with creatinine is known. As a method using an enzyme, for example, there is a method in which ammonia is obtained by decomposing creatinine using creatinine deiminase, and the concentration of creatinine is obtained by measuring the amount of ammonia from a pH change (for example, patents). Reference 2).

  As another method using an enzyme, there is a method of measuring creatinine by the following reactions (Chemical Formula 1) to (Chemical Formula 3).

  As enzymes that catalyze the reactions of (Chemical Formula 1) to (Chemical Formula 3), creatinine amide hydrolase (creatininase), creatine amidinohydrolase (creatinase), and sarcosine oxidase or sarcosine dehydrogenase are used, respectively. Here, as a method for quantifying creatinine, for example, a method in which a leuco dye or a Trinder reagent is used together with peroxidase and the hydrogen peroxide generated in (Chemical Formula 3) is colored and spectroscopically quantified is used. (For example, refer to Patent Document 3). As another creatinine quantification method, a method of electrochemically oxidizing the hydrogen peroxide generated in (Chemical Formula 3) with an electrode and quantifying creatinine from a flowing current is used (see, for example, Patent Documents 4 and 5). ).

  In addition to the reactions of (Chemical Formula 1) and (Chemical Formula 2), in addition to the reactions of (Chemical Formula 3), as another method using an enzyme, the reaction of sarcosine and an electron carrier is used. Has been proposed (see, for example, Patent Documents 6 and 7). Patent Document 6 discloses a reagent solution in which creatininase, creatinase, sarcosine oxidase and an electron carrier are dissolved in a pH 7 to 8.5 buffer in a sensor having at least a pair of working electrodes and counter electrodes on a substrate. A creatinine biosensor is disclosed which is immobilized by drying on an electrode or a substrate around the electrode. Specifically, it is disclosed that potassium ferricyanide is used as an electron carrier, and a phosphate buffer having a pH of 6.86 is used as a buffer. Further, it is disclosed that when the pH of the buffer solution is pH 7 or lower or pH 8.5 or higher, the enzyme activity decreases, which is not preferable. Patent Document 7 discloses that creatinine is measured by a colorimetric method or an electrochemical detection method using a mediator encapsulated by cyclodextrin together with sarcosine oxidase. Specifically, α-naphthoquinone (1,4-naphthoquinone) is mentioned as an example of a mediator incorporated by cyclodextrin. However, in Patent Document 7, when mediators such as α-naphthoquinone and 1-methoxy-5-methylphenazinium methyl sulfate (M-PMS) are not included in cyclodextrin, creatinine is measured using an enzyme. It is disclosed that it is inappropriate.

  In addition to the reactions of (Chemical Formula 1) and (Chemical Formula 2), in addition to the reactions of (Chemical Formula 3), as another method using an enzyme, a reaction between sarcosine and a tetrazolium indicator is used for spectroscopy. In particular, a method for measuring creatinine has been proposed (see, for example, Patent Document 8). Patent Document 8 discloses that a mixed reagent consisting of creatinine hydrolase, creatine amidinohydrolase, sarcosine dehydrogenase, tetrazolium indicator thiazolyl blue and potassium phosphate pH 7.5 is used as a composition for measuring creatinine. .

  In addition, as another method using an enzyme, creatinine amide hydrolase, creatine amidinohydrolase and sarcosine dehydrogenase are used to change creatinine into glycine and formaldehyde. Has been proposed (see, for example, Patent Document 9). In Patent Document 9, in addition to creatinine amide hydrolase, creatine amidinohydrolase, sarcosine dehydrogenase and a colorant, a pH 7.5 phosphate buffer and potassium ferricyanide as a reaction accelerator for promoting the formation of formaldehyde are used. It is disclosed.

  Further, as another method using an enzyme, a method of measuring creatinine using a polymer that catalyzes hydrolysis of creatinine, an electrode on which a sarcosine oxidase and a mediator are immobilized has been proposed (for example, Patent Document 10). reference). Patent Document 10 discloses that potassium ferricyanide, ferrocene, osmium derivatives, phenazine methosulfate (PMS), and the like can be used as mediators.

As another creatinine measurement method, a method using potassium 1,4-naphthoquinone-2-sulfonate has been proposed (for example, see Patent Document 11 and Non-Patent Documents 1 to 3).
US Pat. No. 3,705,003 JP-T-2001-512692 JP-A-62-257400 Special table 2003-533679 gazette US Pat. No. 5,466,575 JP 2006-349412 A JP 2005-1118014 A Japanese Patent Laid-Open No. 55-023998 JP 54-151095 A JP 2003-326172 A JP-A-63-033661 Sullivan, 1 other, “Highly specific test of creatinine”, Journal of Biological Chemistry, 1958, Vol. 233, No. 2, p. 530-534 (Sullivan, “A Highly Specific Test for Creatine”, 1958, Vol. 233, No. 2, p. 530-534) Narayanan, 1 other, “Creatinine: Review”, Clinical Chemistry, 1980, Vol. 26, No. 8, p. 1119-1126 (Narayanan, “Creatinine: A Review”, Clinical Chemistry, 1980, Vol. 26, No. 8, p. 1119-1126) Cooper, et al., “Evaluation of four methods for measuring urinary creatinine”, Clinical Chemistry, 1961, Vol. 7, No. 6, p. 665-673 (Cooper, “An Evaluation of Four Methods of Measuring Primary Creatine”, 1961, Vol. 7, No. 6, P. 665-673)

  However, the conventional method has the following problems.

  In the method described in Patent Document 1, amino acids such as glycine, histidine, glutamine, and serine and sugars such as glucose react with picric acid, and therefore samples containing amino acids and sugars, for example, biological samples such as urine and blood It is difficult to accurately quantify creatinine in it.

  Further, in the method described in Patent Document 2, since changes in pH and potential are unstable, it is difficult to accurately quantify creatinine.

  In addition, in the methods described in Patent Documents 2 to 10, the presence of ionic species such as salinity and urea in the sample causes enzyme activity to be reduced due to denaturation of the enzyme. The reaction rate varies depending on the concentration of. Therefore, when creatinine is quantified in a sample containing ionic species and urea, for example, a biological sample such as urine and blood, an error occurs in the measurement result depending on the concentration of the ionic species and urea contained in the sample.

  In addition, regarding the method using potassium 1,4-naphthoquinone-2-sulfonate described in Patent Document 11 and Non-Patent Document 1, in Non-Patent Documents 2 and 3, the reproducibility of measurement results is very low. A problem has been reported.

  Therefore, in view of the above-described conventional problems, the present invention has a first object to provide a creatinine measurement method, a creatinine measurement device, and a creatinine measurement apparatus that can accurately quantify creatinine contained in a sample. To do.

  It is a second object of the present invention to provide a urinary salt content measuring method, a urinary salt content measuring device, and a urinary salt content measuring apparatus capable of accurately quantifying the salt content in urine. And

In order to solve the above-mentioned conventional problems, the creatinine measurement method of the present invention comprises (A) a sample containing creatinine and a creatinine measurement reagent containing a quinone compound, thereby bringing the creatinine contained in the sample into contact. And a step of directly reacting the quinone compound to produce a reduced product of the quinone compound,
(B) a step of optically measuring the reaction in the step A, and (C) a step of determining the concentration or amount of the creatinine contained in the sample based on the measurement value in the step B.

Moreover, the urinary salt content measuring method of the present invention uses urine as a sample, and in addition to steps A and B of the creatinine measuring method,
(F) a step of measuring electrical characteristics of the urine before the urine and the reagent for measuring creatinine come into contact; and (G) a measured value in the process B and the electrical characteristics measured in the process F. And a step of obtaining a value reflecting the amount of salt excreted in the urine based on the above.

  Further, the creatinine measuring device of the present invention is a creatinine measuring device used in the above creatinine measuring method, and is connected to the sample storing chamber for storing a sample containing creatinine, the sample storing chamber, and the sample storing chamber. A sample introduction port for introducing the sample into the chamber; and a creatinine measurement reagent containing a quinone compound disposed in the sample storage chamber.

  The urinary salt content measuring device of the present invention is a urinary salt content measuring device used in the above urinary salt content measuring method, and includes a first sample storage chamber for storing urine as a sample. A quinone compound in communication with the first sample storage chamber, a first sample introduction port for introducing the urine into the first sample storage chamber, and a quinone compound disposed in the first sample storage chamber; A reagent for measuring creatinine, a second sample storage chamber for storing the urine, and a second sample chamber for communicating with the second sample storage chamber and for introducing the urine into the second sample storage chamber. And at least two electrodes disposed in the second sample storage chamber.

  Further, the creatinine measuring apparatus of the present invention includes a measuring device mounting portion for mounting the creatinine measuring device, a creatinine in the sample storage chamber of the creatinine measuring device mounted on the measuring device mounting portion, and the creatinine measuring reagent. And a calculation unit for optically measuring the reaction with and a calculation unit for obtaining the concentration or amount of the creatinine contained in the sample based on the measurement value in the measurement unit.

  Further, the urinary salt content measuring apparatus of the present invention is a measuring device mounting portion for mounting the urinary salt content measuring device, and the first of the urinary salt content measuring device mounted on the measuring device mounting portion. A first measurement unit for optically measuring the reaction between creatinine and the reagent for measuring creatinine in the sample storage chamber, and the second sample storage of the urinary salt content measurement device attached to the measurement device attachment unit A second measuring unit that measures the electrical characteristics of the urine in the room, and the salinity in the urine based on the measured values in the first measuring unit and the electrical characteristics measured by the second measuring unit. A calculation unit for obtaining a value that reflects the amount of excretion of the animal.

  According to the creatinine measurement method of the present invention, creatinine contained in a sample can be accurately quantified.

  The inventor of the present invention newly found that creatinine and a quinone compound react directly. In this reaction, even in the absence of an enzyme that acts on creatinine, creatinine and a quinone compound react with each other to reduce the amount of creatinine and quinone compound, and creatinine oxide and quinone compound reduced product. And generate.

  The present invention has been made based on the above-mentioned new findings, and is characterized by using a quinone compound as an active ingredient of a reagent composition for measuring creatinine.

In the creatinine measurement method of the present invention, (A) a sample containing creatinine is brought into contact with a creatinine measurement reagent containing a quinone compound, whereby the creatinine contained in the sample reacts directly with the quinone compound. A step of producing a reduced product of the quinone compound,
(B) a step of optically measuring the reaction in the step A, and (C) a step of determining the concentration or amount of the creatinine contained in the sample based on the measurement value in the step B.

  According to this method, unlike conventional measurement methods, creatinine reacts directly with quinone compounds in the absence of an enzyme or picric acid that acts on creatinine, thus interfering with ionic species such as salinity, urea, amino acids, sugars, etc. The reaction proceeds without being affected by the components. Therefore, even when a biological sample such as urine or blood is used, creatinine contained in the sample can be quantified with higher accuracy than conventional measurement methods.

  As the quinone compound used in the present invention, a quinone compound having an oxidation-reduction potential at pH 7 and 25 ° C. which is more positive than −180 mV with respect to a silver-silver chloride electrode (hereinafter abbreviated as “vs Ag / AgCl”) is used. It is preferable. A preferable upper limit value of the oxidation-reduction potential at pH 7 and 25 ° C. is 0 mV (vs Ag / AgCl). A more preferable range of the oxidation-reduction potential of the quinone compound at pH 7 and 25 ° C. is −100 mV to 0 mV (vs Ag / AgCl).

As the quinone compound, 1,2-naphthoquinone (chemical formula: C ₁₀ H ₆ O ₂ ) represented by the structural formula of the following (Chemical Formula 4), 5-hydroxy-1 represented by the structural formula of the following (Chemical Formula 5) , 4-naphthoquinone (chemical formula: C ₁₀ H ₆ O ₃ ) or the like can be used. The oxidation-reduction potential at pH 7 and 25 ° C. is -60 mV (vs Ag / AgCl) for 1,2-naphthoquinone and -180 mV (vs Ag / AgCl) for 5-hydroxy-1,4-naphthoquinone.

  In the step A, a buffer may be brought into contact with the sample.

  Examples of the buffer used in the present invention include phosphate buffers such as dipotassium hydrogen phosphate and potassium dihydrogen phosphate, citric acid buffers, phthalic acid buffers, acetic acid buffers, MES buffers, and the like. Is mentioned.

  In the creatinine measuring method of the present invention, in the step A, it is preferable that the pH of the sample is adjusted to 4 to 8 by bringing the phosphate buffer into contact with the sample. More preferably, the pH of the sample is adjusted to 4-6. More preferably, the pH of the sample is adjusted to 4-5.

  If it does in this way, since the reaction rate of the direct reaction of creatinine and a quinone compound becomes quick, measurement time can be shortened.

  In the creatinine measurement method of the present invention, the phosphate buffer is preferably composed of dipotassium hydrogen phosphate and potassium dihydrogen phosphate. If it does in this way, when these phosphates melt | dissolve in a sample, the pH of the sample after a phosphate buffer will melt | dissolve can be adjusted in the range of 4-8.

  In the creatinine measurement method of the present invention, in step A, the concentration of the phosphate buffer in the sample after the phosphate buffer is dissolved is preferably 5 to 1000 mM. The present inventor has found that the rate of reaction between creatinine and a quinone compound increases as the concentration of phosphate ions increases. If the concentration of the phosphate buffer is 5 mM or more, a sufficient reaction rate can be obtained. 1000 mM is the upper limit of the solubility of the phosphate buffer having a buffering ability to adjust the pH of the sample to 4-8.

In the creatinine measurement method of the present invention, the step B is
(D) irradiating the sample with incident light, and (E) detecting transmitted light transmitted through the sample or reflected light reflected from the sample,
In step C,
The concentration or amount of the creatinine contained in the sample may be determined based on the intensity of the transmitted light or the reflected light detected in the step E.

  In this way, the concentration or amount of creatinine contained in the sample can be easily determined optically.

The urinary salt content measuring method of the present invention uses urine as a sample, and in addition to steps A and B of the above creatinine measuring method,
(F) a step of measuring electrical characteristics of the urine before the urine and the reagent for measuring creatinine come into contact; and (G) a measured value in the process B and the electrical characteristics measured in the process F. And a step of obtaining a value reflecting the amount of salt excreted in the urine based on the above.

  The electrical characteristics of urine before the urine and the creatinine measurement reagent come into contact with each other and the creatinine measurement reagent dissolves in the urine reflect the concentration of the electrolyte contained in the urine. The concentration of the electrolyte contained in urine has a correlation with the concentration of salt contained in urine. Ingredients such as salt are affected by water intake, sweating, etc., and concentrated or diluted to be excreted in urine. For this reason, the concentration of urine components such as salt contained in the urine collected at any time, which is urine collected at any time during the day and at night, varies under the influence of urine concentration / dilution.

  On the other hand, as described above, since creatinine is produced depending on muscle mass, it is known that the amount of creatinine excreted in urine per unit time is constant. Therefore, even when urine is used at any time, for example, the ratio of the measured urinary component concentration to the creatinine concentration (urine component / creatinine ratio) is determined to correct the influence of urine concentration / dilution. be able to.

  According to the urinary salt content measuring method of the present invention, by using the measured value in Step B that accurately reflects the creatinine concentration and the electrical characteristics measured in Step F that reflect the salinity concentration. Since the influence of urine concentration / dilution is accurately corrected, a value that appropriately reflects the amount of salt excreted in urine can be obtained.

  Here, as electrical characteristics of urine, resistance, conductivity, impedance, voltage (or current) signal output with respect to the input current (or voltage) signal, and phase of the input AC signal are output. For example, a phase difference from the phase of the AC signal.

  Examples of values that reflect the amount of urinary salt excretion determined in step G include the amount of salt per unit amount of creatinine, the amount of urinary salt excretion per unit time (for example, one day), and the unit time (for example, one day). The amount of salt intake per hit is listed.

  A creatinine measuring device of the present invention is a creatinine measuring device used in the above creatinine measuring method, and is in communication with the sample storage chamber for storing a sample containing creatinine, and in the sample storage chamber. A sample introduction port for introducing the sample; and a creatinine measurement reagent containing a quinone compound, which is disposed in the sample storage chamber.

  According to this device, unlike conventional measurement devices, creatinine and quinone compounds react directly even in the absence of an enzyme that acts on creatinine or picric acid in the sample storage chamber. The reaction proceeds without being affected by interfering components such as amino acids and sugars. Therefore, even when a biological sample such as urine or blood is used, creatinine contained in the sample can be quantified with higher accuracy than conventional measurement devices.

  The creatinine measuring device of the present invention may further include a phosphate buffer disposed in the sample storage chamber.

  The urinary salt content measuring device of the present invention is a urinary salt content measuring device used in the above urinary salt content measuring method, the first sample storage chamber for storing urine as a sample, A creatinine containing a quinone compound, which is in communication with the first sample storage chamber and is arranged in the first sample storage chamber, and a first sample introduction port for introducing the urine into the first sample storage chamber A measurement reagent, a second sample storage chamber for storing the urine, and a second sample for introducing the urine into the second sample storage chamber in communication with the second sample storage chamber An inlet, and at least two electrodes disposed in the second sample storage chamber. According to this device, it is possible to accurately measure the amount of reaction between creatinine contained in urine and the reagent for measuring creatinine, which accurately reflects creatinine concentration, and electrical characteristics of urine, which reflects salt concentration. it can. By using the reaction amount and the electrical characteristics, the influence of urine concentration / dilution is corrected with high accuracy, so that a value that appropriately reflects the amount of salt excreted in urine can be obtained.

  The creatinine measuring apparatus of the present invention includes a measuring device mounting portion for mounting the creatinine measuring device, a creatinine in the sample storage chamber of the creatinine measuring device mounted on the measuring device mounting portion, and the creatinine measuring reagent. A measurement unit that optically measures a reaction; and a calculation unit that obtains the concentration or amount of the creatinine contained in the sample based on a measurement value in the measurement unit.

  According to this measuring apparatus, the concentration or amount of creatinine contained in a sample can be optically measured using the creatinine measuring device attached to the measuring device attaching portion. Unlike the conventional measurement apparatus, the creatinine measurement apparatus of the present invention reacts directly with creatinine and a quinone compound even in the absence of an enzyme that acts on creatinine or picric acid in a sample storage chamber. The reaction proceeds without being affected by interfering components such as seeds, urea, amino acids and sugars. Therefore, even when a biological sample such as urine or blood is used, creatinine contained in the sample can be quantified with higher accuracy than conventional measurement devices.

  In the creatinine measuring apparatus according to the present invention, the measurement unit has a light source that emits incident light that enters the sample storage chamber of the creatinine measurement device attached to the measurement device mounting unit, and a transmission that passes through the sample storage chamber. A light receiver that detects light or reflected light reflected in the sample storage chamber, and the calculation unit is included in the sample based on the intensity of the transmitted light or the reflected light detected in the light receiver. The concentration or amount of the creatinine may be determined.

  According to this configuration, the concentration or amount of creatinine contained in the sample can be easily determined optically using the creatinine measurement device attached to the measurement device attachment portion.

  A urinary salt content measuring apparatus according to the present invention includes a measurement device attachment portion for attaching the urinary salt content measurement device, and the first sample of the urinary salt content measurement device attached to the measurement device attachment portion. A first measurement unit that optically measures a reaction between creatinine and the reagent for measuring creatinine in the storage chamber, and the urinary salt content measurement device attached to the measurement device mounting portion in the second sample storage chamber Based on the second measurement unit that measures the electrical characteristics of the urine, and the measured values in the first measurement unit and the electrical characteristics measured by the second measurement unit, the excretion of salt in the urine A calculation unit for obtaining a value reflecting the quantity is provided. According to this measuring device, the concentration of urine can be corrected with respect to the electrical characteristics of the measured urine using the urine creatinine concentration quantified with high accuracy. Can be determined.

  According to the urinary salt content measurement method of the present invention, the amount of reaction between creatinine contained in urine and the reagent for measuring creatinine, which accurately reflects the creatinine concentration, and the urine electricity that reflects the salt concentration. By using the characteristics, the influence of concentration / dilution of urine is corrected with high accuracy, so that a value that appropriately reflects the amount of salt excreted in urine can be obtained.

  Examples of the sample include body fluids such as blood, serum, plasma, urine, interstitial fluid, lymph fluid, and saliva in addition to an aqueous solution. In particular, urine is a very effective sample for non-invasive daily health management at home. Since the concentrations of ionic species and urea in these body fluids are relatively high, the effects of the present invention can be obtained very high.

  The material of at least two electrodes in the present invention is preferably one containing at least one of gold, platinum, palladium, an alloy or mixture thereof, and carbon. These materials are chemically and electrochemically stable, and a stable measurement can be realized.

  As the light source in the present invention, any light source may be used as long as it emits light including a wavelength whose absorption intensity changes due to the reaction between the quinone compound and creatinine. Examples of the light source include an LED and a laser.

  In the measurement device of the present invention, it is preferable that the creatinine measurement reagent is provided in a dry state and is disposed so as to dissolve in the sample when the sample is introduced into the sample storage chamber.

  For example, after impregnating a porous carrier composed of glass fiber, filter paper, or the like with a solution containing a creatinine measurement reagent, the creatinine measurement reagent is supported on the carrier by drying, and the carrier contacts the sample. What is necessary is just to provide in a part. Alternatively, the reagent for measuring creatinine may be arranged by directly applying a solution containing the reagent for measuring creatinine on the wall surface of the part in contact with the sample in the measuring device and then drying.

  The measurement device is preferably attached to a measurement device attachment portion of the measurement apparatus in a detachable state. In particular, when a biological fluid such as urine or blood is used, the measuring device is preferably disposable from a hygienic viewpoint.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
Next, the creatinine measuring device according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is an exploded perspective view showing a configuration of a creatinine measuring device according to the present embodiment.

  The creatinine measuring device 400 according to the present embodiment is used in a creatinine measuring method for optically quantifying the concentration of creatinine contained in a sample. The creatinine measuring device 400 according to the present embodiment has a structure in which an insulating first substrate 102 and a second substrate 104 having air holes 108 are combined with a spacer 106 having a slit 110 interposed therebetween. Yes.

  A reagent layer 130 containing a creatinine measurement reagent is disposed on the first substrate 102. The dimensions of the first substrate 102 may be set as appropriate. For example, the width is about 7 mm, the length is about 30 mm, and the thickness is about 0.7 mm.

  Next, a method for manufacturing the creatinine measuring device 400 will be described. In the present embodiment, 1,2-naphthoquinone, which is a quinone compound, is used as an active ingredient of a reagent for measuring creatinine.

First, on a first substrate 102 made of polyethylene terephthalate, an aqueous solution in which 1,2-naphthoquinone, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate, which are creatinine measurement reagents, are dissolved using a microsyringe or the like. After dropping a certain amount, the reagent layer 130 is formed by allowing the first substrate 102 to stand in an environment of room temperature to 30 ° C. and drying. The concentration and amount of the aqueous solution containing the reagent to be applied may be selected according to the required device characteristics and size. For example, the concentration of 1,2-naphthoquinone in the aqueous solution containing the reagent is about 0.5 mM. Yes, the dripping amount is about 0.7 mL. Also, the area of the region for forming the reagent layer 130 may be appropriately selected in view of such as solubility of the reagent to the sample. For example, for the area ² about 3 mm.

  Next, the first substrate 102 on which the reagent layer 130 is formed, the polyethylene terephthalate spacer 106 having the slits 110, and the second substrate 104 having the air holes 108 are combined. An adhesive is applied to each joint portion of the first substrate 102, the spacer 106, and the second substrate 104, and these are bonded to each other, and then pressed to stand and adhere. Instead of this method, after combining without applying an adhesive, the joining portion may be welded by heat or ultrasonic waves using a commercially available welding machine.

  When the first substrate 102, the spacer 106, and the second substrate 104 are combined, the space formed by the slits 110 and the second substrate 104 provided in the first substrate 102, the spacer 106 is stored in the sample. Functions as a chamber. In addition, the opening of the slit 110 functions as the sample inlet 132.

  Next, a creatinine measuring apparatus according to the present embodiment and a creatinine measuring method using the same will be described with reference to FIGS. FIG. 2 is a perspective view showing the appearance of the creatinine measuring apparatus 500 according to the present embodiment, and FIG. 3 is a block diagram showing the configuration of the creatinine measuring apparatus 500.

  First, the configuration of the creatinine measuring apparatus 500 will be described with reference to FIG.

  The casing 202 of the creatinine measuring apparatus 500 is configured to measure the creatinine by the measuring device mounting unit 208 for attaching the creatinine measuring device 400 to the creatinine measuring apparatus 500, the display 204 on which the measurement result is displayed, and the creatinine measuring apparatus 200. A measurement start button 206 for starting is provided.

  Next, the internal structure of the housing 202 of the creatinine measuring apparatus 500 will be described with reference to FIG.

  The creatinine measuring apparatus 500 includes a light source 502, a light receiver 504, a control unit 306, a timer unit 308, and a storage unit 310 inside the housing 202.

  The light source 502 has a function of emitting light that enters the sample storage chamber of the creatinine measurement device 400 attached to the measurement device attachment unit 208. The wavelength of the light emitted from the light source 502 may be selected such that the absorption intensity changes due to the reaction between 1,2-naphthoquinone and creatinine. As the light source 502, for example, a purple LED that emits light in a wavelength range including 410 nm is used.

  The light receiver 504 has a function of detecting light emitted from the light source 502 and reflected in the sample storage chamber of the creatinine measurement device 400 attached to the measurement device attachment unit 208.

  The storage unit 310 stores correlation data corresponding to a calibration curve representing the correlation between the concentration of creatinine and the intensity of reflected light detected by the light receiver 504. As the storage unit 310, for example, a memory such as a RAM or a ROM can be used.

  The control unit 306 has a function of converting the intensity of the reflected light detected by the light receiver 504 into a creatinine concentration with reference to the correlation data. The control unit 306 corresponds to the calculation unit in the present invention. As the control unit 306, for example, a microcomputer such as a CPU (Central Processing Unit) can be used.

  Next, a creatinine measurement method according to the present embodiment using the creatinine measurement device 400 and the creatinine measurement apparatus 500 will be described.

  First, the user inserts the side opposite to the sample introduction port 132 of the creatinine measuring device 400 into the measuring device mounting portion 208 of the creatinine measuring apparatus 500.

  When the creatinine measurement device 400 is inserted into the measurement device attachment unit 208, a measurement device insertion detection switch including a micro switch provided in the measurement device attachment unit 208 is activated and outputs a signal to the control unit 306. When the control unit 306 detects the insertion of the creatinine measurement device 400 based on the output signal from the measurement device insertion detection switch, the control unit 306 activates the light source 502. As a result, the sample storage chamber of the creatinine measuring device 400 is irradiated with the light from the light source 502.

  Next, the user brings the sample into contact with the sample inlet 132 of the creatinine measuring device 400. By this contact, the sample is sucked into the sample storage chamber of the creatinine measuring device 400 through the sample introduction port 132 by capillary action, and the sample storage chamber is filled with the sample. When the light irradiation position in the sample storage chamber is reached, the transmittance changes, and the light receiver 504 detects a change in the reflected light intensity due to this.

  When the control unit 306 detects that the sample has been introduced into the sample storage chamber based on the output signal from the light receiver 504, the control unit 306 starts timing by the timer unit 308 that is a timer.

  When the reagent layer 130 exposed in the sample storage chamber comes into contact with the sample, 1,2-naphthoquinone in the creatinine measurement reagent contained in the reagent layer 130 is dissolved in the sample. The 1,2-naphthoquinone dissolved in the sample reacts directly with the creatinine contained in the sample, whereby creatinine oxide and reduced 1,2-naphthoquinone are generated. Reduction of 1,2-naphthoquinone changes the absorption spectrum of the sample. Here, the amount of change in the absorption spectrum of the sample depends on the concentration of the reduced 1,2-naphthoquinone.

  When the control unit 306 determines that a predetermined time (for example, 60 seconds) has elapsed based on a signal from the time measuring unit 308, the intensity of the light reflected in the sample storage chamber is measured by the light receiver 504. At this time, the intensity of the reflected light measured by the light receiver 504 depends on the concentration of creatinine contained in the sample.

  The control unit 306 reads correlation data corresponding to a calibration curve representing the correlation between the concentration of creatinine stored in the storage unit 310 and the intensity of the reflected light detected by the light receiver 504, and receives light by referring to it. The intensity of the reflected light detected in the vessel 504 is converted into the creatinine concentration in the sample.

  The obtained creatinine concentration is displayed on the display 204. By displaying the creatinine concentration on the display 204, the user knows that the creatinine concentration measurement has been completed. The obtained creatinine concentration is preferably stored in the storage unit 310 together with the time measured by the time measuring unit 308.

  According to the creatinine measuring device 400 according to the present embodiment, unlike the conventional measuring device, creatinine and 1,2-naphthoquinone are present in the sample storage chamber even if there is no enzyme or picric acid acting on creatinine. Since it reacts directly, the reaction proceeds without being affected by interfering components such as ionic species such as salt, urea, amino acids, and sugars. Therefore, even when a biological sample such as urine or blood is used, creatinine contained in the sample can be quantified with higher accuracy than conventional measurement devices.

  In the present embodiment, an example is shown in which 1,2-naphthoquinone is used as an active ingredient in the reagent for measuring creatinine, but 5-hydroxy-1,4-naphthoquinone may be used instead. Even when 5-hydroxy-1,4-naphthoquinone is used as an active ingredient of a reagent for measuring creatinine, it is not affected by interfering components such as ionic species such as salt, urea, amino acid, sugar, etc. Can accurately quantify creatinine contained in the sample.

  Moreover, in this Embodiment, it is not limited to this which showed the example in which a creatinine measuring device is provided with one reagent layer. The creatinine measuring device may include two reagent layers, for example, a first reagent layer containing a creatinine measuring reagent and a second reagent layer containing a phosphate buffer.

  In the present embodiment, an example in which the time (reaction time) until detection of the reflected light intensity after detection of the sample is set to 60 seconds is shown, but the value is not necessarily required. As long as the difference in reflected light intensity with respect to the difference in creatinine concentration can be detected significantly, a smaller reaction time can be used as the reaction time. On the other hand, when the reaction time is increased, the possibility that the reaction between creatinine and 1,2-naphthoquinone reaches a complete state or a steady state increases, so the amount of creatinine is reduced without being affected by environmental conditions such as temperature. It becomes easy to quantify more accurately.

  Further, in order to more smoothly introduce the sample into the sample storage chamber of the creatinine measuring device, a solution obtained by dissolving lecithin in toluene or other organic solvent is applied to the inner wall of the second substrate and dried. A lecithin layer may be formed. By adopting such a structure, the amount of the sample can be made constant with higher reproducibility, so that creatinine contained in the sample can be quantified with higher accuracy.

  The creatinine measuring apparatus may further include a recording unit for recording the creatinine concentration obtained as a measurement result on a storage medium such as an SD card. By storing in a removable storage medium, the measurement result can be easily taken out from the creatinine measurement device, so that it becomes easy to request an analysis related company to analyze the measurement result.

  Moreover, the creatinine measuring device may further include a transmission unit for transmitting the creatinine concentration obtained as a measurement result to the outside of the creatinine measuring device. As a result, measurement results can be sent to analysis-related departments or analysis-related contractors in hospitals and analyzed at analysis-related departments or analysis-related contractors, so the time from measurement to analysis can be reduced. .

  The creatinine measuring apparatus may further include a receiving unit for receiving the result of analysis in an analysis related department or an analysis related business. As a result, the analysis result can be quickly fed back to the user.

(Embodiment 2)
Next, a urinary salt content measuring device according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 4 is an exploded perspective view showing a configuration of the urinary salt content measuring device according to the present embodiment as viewed from the first surface side of the first substrate, and FIG. 5 is a urinary salt content according to the present embodiment. It is a disassembled perspective view which shows the structure which looked at the measuring device from the 2nd surface side of the 1st board | substrate.

  The urinary salt content measuring device 700 according to the present embodiment optically measures creatinine contained in urine as a sample, and measures electrical characteristics of urine, and uses these measurement results for one day. It is used in a method for estimating the amount of salt contained in excreted urine.

  In the urinary salt content measuring device 700 according to the present embodiment, the first substrate 102 having the insulating property and the second substrate 104 having the air holes 108 are connected to the first surface 702 of the first substrate 102 and the first substrate 702. The third substrate 704 having the first spacer 102 having the slit 110 and the insulating first substrate 102 and the air hole 708 is combined with the first spacer 106 so as to be in contact with the first spacer 106. 102 has a structure in which a second spacer 706 having a slit 710 is sandwiched so that the second surface 802 of 102 and the second spacer 706 are in contact with each other.

  Similar to the creatinine measuring device 100 according to the first embodiment, a reagent layer 130 containing a creatinine measuring reagent is disposed on the first surface 702 of the first substrate 102.

  On the other hand, the first electrode 712, the second electrode 714, the third electrode 716, the fourth electrode 718, and the first electrode 712 are electrically connected to the second surface 802 of the first substrate 102. The first lead 722 connected, the second lead 724 electrically connected to the second electrode 714, the third lead 726 electrically connected to the third electrode 716, and the fourth electrode A fourth lead 728 electrically connected to 718 is disposed. The dimensions of the first substrate 102 may be set as appropriate. For example, the width is about 7 mm, the length is about 30 mm, and the thickness is about 0.7 mm.

  Next, a method for manufacturing the urinary salt content measuring device 700 will be described.

  First, palladium is sputtered on a second surface 802 of a first substrate 102 made of polyethylene terephthalate with a resin electrode pattern mask placed thereon, whereby a first electrode 712 and a second electrode 714 are formed. , Third electrode 716, fourth electrode 718, first lead 722, second lead 724, third lead 726, and fourth lead 728 are formed. The first electrode 712, the second electrode 714, the third electrode 716, and the fourth electrode 718 are a first lead 722, a second lead 724, a third lead 726, and a fourth lead, respectively. 728 is electrically connected to a terminal of a urinary salt content measuring device described later.

Next, an aqueous solution in which 1,2-naphthoquinone, potassium dihydrogen phosphate, and dipotassium hydrogen phosphate, which are creatinine measurement reagents, are dissolved on the first surface 702 of the first substrate 102 is a microsyringe or the like. Then, the first substrate 102 is left standing in an environment of room temperature to about 30 ° C. and dried to form the reagent layer 130. The concentration and amount of the aqueous solution containing the reagent to be applied may be selected according to the required device characteristics and size. For example, the concentration of 1,2-naphthoquinone in the aqueous solution containing the reagent is about 0.5 mM. Yes, the dripping amount is about 0.7 mL. Also, the area of the region for forming the reagent layer 130 may be appropriately selected in view of such as solubility of the reagent to the sample. For example, for the area ² about 3 mm.

  Next, the air holes 108 are formed so that the first surface 702 of the first substrate 102 is in contact with the first spacer 106 and the second surface 802 of the first substrate 102 is in contact with the second spacer 706. A second substrate 104 having a slit, a first spacer 106 made of polyethylene terephthalate having a slit 110, a first substrate 102, a second spacer 706 made of polyethylene terephthalate having a slit 710, and a third having an air hole 708. The substrate 704 is combined. An adhesive is applied to each joint portion of each member, and after pasting them together, they are pressed and allowed to stand and adhere. Instead of this method, after combining without applying an adhesive, the joining portion may be welded by heat or ultrasonic waves using a commercially available welding machine.

  When the first substrate 102, the first spacer 106, and the second substrate 104 are combined, the first substrate 102, the slit 110 provided in the first spacer 106, and the second substrate 104 are formed. The space functions as a first sample storage chamber for creatinine measurement. Further, the opening of the slit 110 functions as a first sample introduction port 132 for measuring creatinine.

  On the other hand, when the first substrate 102, the second spacer 706, and the third substrate 704 are combined, the first substrate 102, the slit 710 provided in the second spacer 706, and the third substrate 704 are formed. The space portion to be functioned as a second sample storage chamber for electrical characteristics of urine. Further, the opening of the slit 710 functions as a second sample introduction port 732 for electrical characteristics of urine.

  Next, a urinary salt content measuring apparatus and a urinary salt content measuring method using the same according to the present embodiment will be described with reference to FIGS. FIG. 6 is a perspective view showing the external appearance of the urinary salt content measuring apparatus 900 according to the present embodiment, and FIG. 7 is a block diagram showing the configuration of the urinary salt content measuring apparatus 900.

  First, the configuration of the urinary salt content measuring apparatus 900 will be described with reference to FIG.

  The housing 202 of the urinary salt content measuring apparatus 900 has a measurement device mounting unit 208 for attaching the urinary salt content measuring device 700 to the urinary salt content measuring apparatus 900, a display 204 on which measurement results and the like are displayed, and A measurement start button 206 for starting measurement of the electrical characteristics of creatinine and urine by the urinary salt content measuring apparatus 900 is provided. In addition, the first lead 722, the second lead 724, the third lead 726, and the fourth lead of the urinary salt content measuring device 700 attached to the measuring device attaching part 208 are provided inside the measuring device attaching part 208. A first terminal, a second terminal, a third terminal, and a fourth terminal that are respectively electrically connected to the lead 728 are provided.

  Next, the internal structure of the housing 202 of the urinary salt content measuring apparatus 900 will be described with reference to FIG.

  The urinary salt content measuring apparatus 900 includes a light source 502, a light receiver 504, a constant current AC power source 902, a voltage detector 904, a control unit 306, a time measuring unit 308, and a storage unit 310 inside the housing 202.

  The light source 502 has a function of emitting light that enters the first sample storage chamber of the urinary salt content measurement device 700 attached to the measurement device attachment unit 208. The wavelength of the light emitted from the light source 502 may be selected such that the absorption intensity changes due to the reaction between 1,2-naphthoquinone and creatinine. As the light source 502, for example, a purple LED that emits light in a wavelength range including 410 nm is used.

  The light receiver 504 has a function of detecting light emitted from the light source 502 and reflected in the first sample storage chamber of the urinary salt content measurement device 700 attached to the measurement device attachment unit 208.

  The constant current AC power source 902 includes a first terminal and a fourth terminal electrically connected to the first lead 722 and the fourth lead 728 of the urinary salt content measurement device 700 attached to the measurement device attachment unit 208, respectively. The terminal has a function of applying a constant alternating current between the first electrode 712 and the fourth electrode 718 of the urinary salt content measuring device 700 through the terminal. The alternating current to be applied has, for example, a frequency of about 1 kHz and a current value of about 0.1 mA.

  The voltage detector 904 has a function of detecting a voltage (effective value of an alternating voltage) between the second electrode 714 and the third electrode 716 through the second terminal and the third terminal.

  The storage unit 310 detects the first correlation data corresponding to the first calibration curve representing the correlation between the concentration of creatinine and the intensity of the reflected light detected by the light receiver 504, detected by the salt concentration and voltage detector 904. Second correlation data corresponding to a second calibration curve representing the correlation with the applied voltage, and a third calibration curve representing the correlation between the daily urinary salt excretion amount and the salt concentration corrected by the creatinine concentration The third correlation data corresponding to is stored. As the storage unit 310, for example, a memory such as a RAM or a ROM can be used.

  The control unit 306 refers to the first correlation data, functions to convert the intensity of the reflected light detected by the light receiver 504 into a creatinine concentration, and refers to the second correlation data to be detected by the voltage detector 904. The function to convert the measured voltage into the salt concentration, the function to correct the salt concentration using the obtained creatinine concentration, and the third correlation data, the corrected salt concentration is excreted in the urine salt per day Has the function of converting to quantity. The control unit 306 corresponds to the calculation unit in the present invention. As the control unit 306, for example, a microcomputer such as a CPU (Central Processing Unit) can be used.

  Next, the urinary salt content measuring method according to the present embodiment using the urinary salt content measuring device 700 and the urinary salt content measuring apparatus 900 will be described.

  First, the user inserts the lead side of the urinary salt content measurement device 700 into the measurement device mounting portion 208 of the urinary salt content measurement device 900. Accordingly, the first lead 722, the second lead 724, the third lead 726, and the fourth lead 728 of the urinary salt content measuring device 700 and the first provided in the measurement device mounting portion 208 are provided. The terminals, the second terminal, the third terminal, and the fourth terminal are electrically connected to each other.

  When the urinary salt content measurement device 700 is inserted into the measurement device attachment unit 208, a measurement device insertion detection switch including a micro switch provided in the measurement device attachment unit 208 is activated to output a signal to the control unit 306. To do. When the control unit 306 detects the insertion of the urinary salt content measurement device 700 based on the output signal from the measurement device insertion detection switch, the control unit 306 activates the light source 502. As a result, the light from the light source 502 is applied to the first sample storage chamber of the urinary salt content measurement device 700.

  Next, the user brings the sample into contact with the first sample inlet 132 and the second sample inlet 732 of the urinary salt content measuring device 700. By this contact, the sample is sucked into the two sample storage chambers of the urinary salt content measuring device 700 through the first sample introduction port 132 and the second sample introduction port 732 by capillary action, and thus the two sample storage chambers. Is filled with the sample. Since the transmittance changes when the sample reaches the light irradiation position in the first sample storage chamber, the light receiver 504 detects a change in reflected light intensity due to the change.

  When the control unit 306 detects that the sample has been introduced into the sample storage chamber based on the output signal from the light receiver 504, the control unit 306 starts timing by the timer unit 308 that is a timer.

  In addition, along with the detection of the sample introduction, the control unit 306 controls the constant current AC power source 902 to connect the first electrode 712 and the fourth electrode 718 via the first terminal and the fourth terminal. A constant alternating current (for example, frequency of 1 kHz, current value of 0.1 mA) is applied to. The voltage detector 904 measures the voltage (effective value of the alternating current) between the second electrode 714 and the third electrode 716 after a predetermined time has elapsed from the application of the alternating current (for example, after 5 seconds).

  The control unit 306 reads the second correlation data representing the correlation between the salinity concentration stored in the storage unit 310 and the voltage detected by the voltage detector 904, and the voltage detector 904 detects the correlation data by referring to it. The applied voltage is converted to the salinity concentration in the sample. The obtained salinity concentration is displayed on the display 204. The obtained salt concentration is preferably stored in the storage unit 310 together with the time measured by the time measuring unit 308.

  When the reagent layer 130 exposed in the first sample storage chamber for creatinine measurement comes into contact with the sample, 1,2-naphthoquinone in the creatinine measurement reagent contained in the reagent layer 130 is dissolved in the sample. The 1,2-naphthoquinone dissolved in the sample reacts directly with the creatinine contained in the sample, whereby creatinine oxide and reduced 1,2-naphthoquinone are generated. Reduction of 1,2-naphthoquinone changes the absorption spectrum of the sample. Here, the amount of change in the absorption spectrum of the sample depends on the concentration of the reduced 1,2-naphthoquinone.

  When the control unit 306 determines that a predetermined time (for example, 60 seconds) has elapsed based on a signal from the time measuring unit 308, the intensity of the light reflected in the sample storage chamber is measured by the light receiver 504. At this time, the intensity of the reflected light measured by the light receiver 504 depends on the concentration of creatinine contained in the sample.

  The control unit 306 reads the first correlation data representing the correlation between the creatinine concentration stored in the storage unit 310 and the intensity of the reflected light detected by the light receiver 504, and by referring to it, the light receiver 504 The intensity of the detected reflected light is converted into the creatinine concentration in the sample.

  Next, the control unit 306 corrects the salinity concentration using the obtained creatinine concentration. Subsequently, the control unit 306 stores third correlation data corresponding to a third calibration curve representing the correlation between the daily urinary salt excretion amount stored in the storage unit 310 and the salt concentration corrected by the creatinine concentration. Is read, and the corrected salt concentration is converted into the amount of urinary salt excretion per day.

  The obtained creatinine concentration and the daily urinary salt excretion amount are displayed on the display 204. By displaying the creatinine concentration and the daily urinary salt excretion amount on the display 204, the user knows that the measurement has been completed. The obtained creatinine concentration and daily urinary salt excretion amount are preferably stored in the storage unit 310 together with the time measured by the time measuring unit 308.

  According to the urinary salt content measuring device 700 according to the present embodiment, unlike the conventional measuring device, creatinine and 1,2-in the sample storage chamber even if there is no enzyme or picric acid acting on creatinine. Since naphthoquinone reacts directly, the reaction proceeds without being affected by interfering components such as ionic species such as salt, urea, amino acids, and sugars. Therefore, even when a biological sample such as urine or blood is used, creatinine contained in the sample can be quantified with higher accuracy than conventional measurement devices.

  Moreover, according to the urinary salt amount measuring apparatus 900 according to the present embodiment, the urinary salt excretion amount per day is calculated based on the salt concentration corrected by the creatinine concentration measured with high accuracy. Therefore, the amount of urinary salt excretion per day can be obtained with high accuracy.

  In the present embodiment, an example is shown in which 1,2-naphthoquinone is used as an active ingredient in the reagent for measuring creatinine, but 5-hydroxy-1,4-naphthoquinone may be used instead. Even when 5-hydroxy-1,4-naphthoquinone is used as an active ingredient in a reagent for measuring creatinine, a conventional measuring device is not affected by interfering components such as ionic species such as salt, urea, amino acids, and sugars. The creatinine contained in the sample can be quantified with higher accuracy.

  Moreover, in this Embodiment, it is not limited to this which showed the example in which the urinary salt content measuring device is provided with one reagent layer. The urinary salt content measuring device may include two reagent layers, for example, a first reagent layer containing a reagent for measuring creatinine and a second reagent layer containing a phosphate buffer.

  In the present embodiment, an example in which the time (reaction time) until detection of an electrical signal after detection of a sample is set to 60 seconds is shown, but the value is not necessarily required. As long as a difference in current value with respect to a difference in creatinine concentration can be detected significantly, a reaction time smaller than the above can be used. On the other hand, when the reaction time is increased, the possibility that the reaction between creatinine and 1,2-naphthoquinone reaches a complete state or a steady state increases, so the amount of creatinine is reduced without being affected by environmental conditions such as temperature. It becomes easy to quantify more accurately.

  Further, in the present embodiment, the storage unit stores the first correlation data corresponding to the first calibration curve representing the correlation between the concentration of creatinine and the intensity of the reflected light detected by the light receiver 504, the salt concentration, The second correlation data corresponding to the second calibration curve representing the correlation with the voltage detected by the voltage detector 904, and the correlation between the daily urinary salt excretion amount and the salt concentration corrected by the creatinine concentration Although the example in which the third correlation data corresponding to the third calibration curve to be expressed is stored is shown, the present invention is not limited to this. Instead, correlation data indicating the correlation between the intensity of reflected light detected by the light receiver, the voltage detected by the voltage detector, and the amount of urinary salt excretion per unit time (for example, one day) is stored in the storage unit. It may be stored. In this case, the urinary salt excretion per unit time can be directly calculated using the intensity of the reflected light detected by the light receiver and the voltage detected by the voltage detector without obtaining the creatinine concentration and the salt concentration. Can be sought.

  In order to more smoothly introduce the sample into the sample storage chamber of the urinary salt content measuring device, a solution obtained by dissolving lecithin in toluene or another organic solvent is used as the inner wall of the second substrate and the third substrate. You may form a lecithin layer by apply | coating to and drying. By adopting such a structure, the amount of the sample can be made constant with higher reproducibility, so that creatinine and salt contained in the sample can be quantified with higher accuracy.

  The urinary salt content measuring device may further include a recording unit for recording the creatinine concentration, the salinity concentration, and the daily urinary salt excretion obtained as a measurement result in a storage medium such as an SD card. Good. By storing in the removable storage medium, the measurement result can be easily taken out from the urinary salt content measuring device, so that it becomes easy to request the analysis related company to analyze the measurement result.

  The urinary salt content measuring device further includes a transmission unit for transmitting the creatinine concentration, the salinity concentration and the daily urinary salt excretion obtained as a measurement result to the outside of the urinary salt content measuring device. Also good. As a result, measurement results can be sent to analysis-related departments or analysis-related contractors in hospitals and analyzed at analysis-related departments or analysis-related contractors, so the time from measurement to analysis can be reduced. .

  In addition, the urinary salt content measuring device may further include a receiving unit for receiving the result of analysis in an analysis related department or an analysis related business. As a result, the analysis result can be quickly fed back to the user.

Example 1
In order to confirm the effect of the creatinine measuring method according to the present invention, the following experiment was conducted. In this example, 1,2-naphthoquinone, which is a quinone compound, is used as an active ingredient in a reagent for measuring creatinine, and urine is used as a sample containing creatinine.

  First, a 100 mM dipotassium hydrogen phosphate aqueous solution and a 100 mM potassium dihydrogen phosphate aqueous solution were prepared. The two aqueous solutions were alternately mixed while monitoring with a pH meter, thereby adjusting the pH of the resulting mixed aqueous solution to 7. An aqueous 1,2-naphthoquinone solution was prepared by dissolving 1,2-naphthoquinone in a 100 mM phosphate buffer solution (pH = 7) thus obtained to a concentration of 0.1 mM.

  The obtained 1,2-naphthoquinone aqueous solution was put into a glass cell container, and an absorption spectrum was measured for a wavelength range of 250 to 750 nm using an absorptiometer (manufactured by Shimadzu Corporation, model: MultiSpec-1500). Next, urine was put into another glass cell container, and an absorption spectrum was measured for a wavelength range of 250 to 750 nm using the same absorptiometer. The above experiment was performed at room temperature (about 25 ° C.).

  The measurement result will be described with reference to FIG. FIG. 8 is a graph showing the absorption spectra measured for the 1,2-naphthoquinone aqueous solution and urine. In FIG. 8, the horizontal axis indicates the wavelength (nm), the vertical axis indicates the absorbance (arbitrary intensity), the line A indicates the absorption spectrum of the 1,2-naphthoquinone aqueous solution, and the line B indicates the absorption spectrum of urine.

  As can be seen from FIG. 8, the 1,2-naphthoquinone aqueous solution has an absorption peak centered at about 350 nm and an absorption peak centered at about 410 nm. On the other hand, in the absorption region of 1,2-naphthoquinone existing at about 300 to 500 nm, urine has a gentle absorption, but the absorbance of 1,2-naphthoquinone absorption is higher than that of urine absorption. It can be seen that it is significantly larger. From this result, it was found that the absorbance change of the absorption of 1,2-naphthoquinone accompanying the reaction between 1,2-naphthoquinone and creatinine contained in urine can be measured.

  Therefore, using the creatinine measuring device 400 and the creatinine measuring apparatus 500 according to Embodiment 1 of the present invention, for example, the creatinine concentration contained in urine can be quantified as follows.

  For example, a violet LED that emits light in a wavelength range including 410 nm is used as the light source 502.

First, when the user brings urine into contact with the sample inlet 132 of the creatinine measuring device 400, urine is sucked into the sample storage chamber of the creatinine measuring device 400 through the sample inlet 132. When urine reaches the light irradiation position in the sample storage chamber, the reflectance changes, and the reflected light intensity detected by the light receiver 504 changes. The reflected light intensity A ₀ detected by the light receiver 504 at this time is a value measured immediately after the creatinine measurement reagent contained in the reagent layer 130 is dissolved in urine. This corresponds to the sum of the absorbance A (U) at 410 nm of urine itself and the absorbance A (Q) at 410 nm of 1,2-naphthoquinone.

  Next, when the control unit 306 determines that a predetermined time (for example, 60 seconds) has elapsed based on a signal from the time measuring unit 308, the intensity of the light reflected in the sample storage chamber is measured by the light receiver 504. At this time, the reflected light intensity A detected by the light receiver 504 includes the absorbance A (U) at 410 nm of urine itself, creatinine and 1,2-naphthoquinone contained in urine, as shown in the following (Equation 2). This corresponds to the sum of the absorbance A (Q) at 410 nm of unreacted 1,2-naphthoquinone that was not involved in the reaction with.

Therefore, as shown in the following (Equation 3), when the difference between the reflected light intensity A ₀ and the reflected light intensity A is obtained, the absorbance A (U) at 410 nm of urine itself is not included, and creatinine contained in urine is The value reflects the concentration of reacted 1,2-naphthoquinone.

Therefore, if correlation data corresponding to a calibration curve representing the correlation between the concentration of creatinine and the difference between the reflected light intensity A ₀ detected by the light receiver 504 and the reflected light intensity A is stored in the storage unit 310 in advance, The control unit 306 reads the correlation data and refers to it, whereby the difference between the reflected light intensity A ₀ and the reflected light intensity A detected by the light receiver 504 can be converted into the creatinine concentration in urine.

  The present invention is useful for quantifying creatinine contained in a sample, particularly a biological sample such as urine.

The disassembled perspective view which shows the structure of the creatinine measuring device in one embodiment of this invention The perspective view which shows the external appearance of the creatinine measuring apparatus in the embodiment Block diagram showing the configuration of the creatinine measuring apparatus The disassembled perspective view which shows the structure which looked at the urinary salt content measuring device in other embodiment of this invention from the 1st surface side of the 1st board | substrate. The exploded perspective view which shows the structure which looked at the salt content measuring device in the urine from the 2nd surface side of the 1st board | substrate. The perspective view which shows the external appearance of the urinary salt content measuring apparatus in the embodiment Block diagram showing the configuration of the urinary salt content measuring device The graph which shows the absorption spectrum measured about 1, 2- naphthoquinone aqueous solution and urine in one Example of this invention

Explanation of symbols

102 1st board | substrate 104 2nd board | substrate 106 Spacer (1st spacer)
108,708 Air hole 110,710 Slit 130 Reagent layer 132 Sample inlet (first sample inlet)
202 Case 204 Display 206 Measurement Start Button 208 Measurement Device Mounting Unit 302 Voltage Application Unit 304 Electric Signal Detection Unit 306 Control Unit 308 Timekeeping Unit 310 Storage Unit 400 Creatinine Measuring Device 500 Creatinine Measuring Device 502 Light Source 504 Light Receiver 700 Urinary Salt Content Measurement device 702 First surface 704 Third substrate 706 Second spacer 712 First electrode 714 Second electrode 716 Third electrode 718 Fourth electrode 722 First lead 724 Second lead 726 Third Lead 728 Fourth lead 732 Second sample inlet 802 Second surface 900 Urine salt content measuring device 902 Constant current AC power source 904 Voltage detector

Claims (14)

(A) By bringing a sample containing creatinine into contact with a reagent for measuring creatinine containing a quinone compound, the creatinine contained in the sample reacts directly with the quinone compound, thereby reducing the quinone compound. The process of generating
(B) A step of optically measuring the reaction in the step A, and (C) a method for measuring the concentration or amount of the creatinine contained in the sample based on the measurement value in the step B. The method for measuring creatinine according to claim 1, wherein the oxidation-reduction potential of the quinone compound at pH 7 and 25 ° C is more positive than -180 mV with respect to the silver-silver chloride electrode. The method for measuring creatinine according to claim 1 or 2, wherein the quinone compound is 1,2-naphthoquinone. In step A,
The creatinine measuring method according to any one of claims 1 to 3, wherein the pH of the sample is adjusted to 4 to 8 by bringing a phosphate buffer into contact with the sample. Step B is
(D) irradiating the sample with incident light, and (E) detecting transmitted light transmitted through the sample or reflected light reflected from the sample,
In step C,
The creatinine measuring method according to any one of claims 1 to 4, wherein the concentration or amount of the creatinine contained in the sample is obtained based on the intensity of the transmitted light or the reflected light detected in the step E. . Using urine as a sample,
In addition to steps A and B of the method for measuring creatinine according to claim 1,
(F) a step of measuring electrical characteristics of the urine before the urine and the reagent for measuring creatinine come into contact; and (G) a measured value in the process B and the electrical characteristics measured in the process F. A method for measuring urinary salt content, further comprising a step of obtaining a value reflecting the amount of salt excreted in urine based on the above. A creatinine measuring device used in the creatinine measuring method according to claim 1,
A sample storage chamber for storing a sample containing creatinine;
A sample inlet for communicating with the sample storage chamber and for introducing the sample into the sample storage chamber;
A creatinine measurement device comprising a creatinine measurement reagent containing a quinone compound, which is disposed in the sample storage chamber. The creatinine measuring device according to claim 7, wherein the oxidation-reduction potential of the quinone compound at pH 7 and 25 ° C is more positive than -180 mV with respect to the silver-silver chloride electrode. The creatinine measuring device according to claim 7 or 8, wherein the quinone compound is 1,2-naphthoquinone. The creatinine measuring device according to any one of claims 7 to 9, further comprising a phosphate buffer disposed in the sample storage chamber. A urinary salt content measuring device used in the urinary salt content measuring method according to claim 6,
A first sample storage chamber for storing urine as a sample;
A first sample inlet for communicating with the first sample storage chamber and for introducing the urine into the first sample storage chamber;
A creatinine measurement reagent containing a quinone compound, disposed in the first sample storage chamber;
A second sample storage chamber for storing the urine;
A second sample inlet for communicating with the second sample storage chamber and for introducing the urine into the second sample storage chamber;
A urinary salt content measuring device comprising: at least two electrodes arranged in the second sample storage chamber. A measuring device mounting portion for mounting the creatinine measuring device according to claim 7,
A measuring unit that optically measures a reaction between the creatinine measuring device and the creatinine measuring reagent in the sample storage chamber of the creatinine measuring device attached to the measuring device mounting unit, and the sample based on the measured value in the measuring unit A creatinine measuring apparatus comprising a calculation unit for obtaining the concentration or amount of the creatinine contained in the creatinine. The measurement unit is
A light source that emits incident light that enters the sample storage chamber of the creatinine measurement device attached to the measurement device mounting portion, and transmitted light that has passed through the sample storage chamber or reflected light that has been reflected in the sample storage chamber is detected. Having a receiver
The computing unit is
The creatinine measuring apparatus according to claim 12, wherein the concentration or amount of the creatinine contained in the sample is obtained based on the intensity of the transmitted light or the reflected light detected by the light receiver. A measuring device mounting portion for mounting the urinary salt content measuring device according to claim 11,
A first measurement unit for optically measuring a reaction between creatinine and the creatinine measurement reagent in the first sample storage chamber of the urinary salt content measurement device attached to the measurement device attachment unit;
A second measurement unit for measuring electrical characteristics of the urine in the second sample storage chamber of the urinary salt content measurement device attached to the measurement device attachment unit; and a measurement value in the first measurement unit; A urinary salt content measuring device including a calculation unit that obtains a value reflecting the amount of salt excreted in the urine based on the electrical characteristics measured by the second measuring unit.

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