JP3926658B2 - Sugar detection apparatus and sugar detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sugar detection / detection device, and more particularly, a sugar detection device capable of maintaining high sensitivity even when used for a long period of time, and a high sensitivity even after being used for a long period of time. In addition, the present invention relates to a sugar detection method capable of obtaining a highly stable measurement value.
[0002]
[Prior art]
Sugar analysis is carried out in a wide range of fields. For example, in the medical field, sugar analysis is carried out for measurement of sugar concentration in blood, that is, blood sugar level.
[0003]
In blood glucose level measurement, conventionally, blood was collected from the fingertip and the blood glucose level was directly measured for each blood sample solution. However, this method does not allow continuous measurement, and There was the disadvantage of causing pain to the patient.
[0004]
Therefore, a sugar detection device utilizing current measurement using an electrode has been developed. In this sugar detection device, saliva or the like is used as a sample, an electrode is immersed in the sample solution, and the current generated when the sugar in the saliva reacts on the electrode is measured. The blood glucose level is obtained from the relationship with the sugar concentration.
[0005]
In the conventional sugar detection apparatus of this type, an enzyme electrode is used as an electrode. In a sugar detection apparatus using this enzyme electrode, for example, an enzyme film made of glucose oxidase and peroxidase is formed on a platinum electrode, and sugar is oxidized by these enzymes, and the current generated at that time is measured. According to this sugar detection apparatus, it is possible to perform continuous measurement while immersing the electrode in the sample solution, and there is no need to collect blood, so that there is no pain for the patient.
[0006]
However, since this conventional sugar detection apparatus uses an enzyme, the sensitivity is lowered due to the inactivation of the enzyme with the passage of time, and there is a disadvantage that it cannot be used for a long time.
[0007]
In addition, this conventional sugar detection device has a drawback that when the sample solution contains impurities such as protein or lipid, the measured value varies greatly due to the adhesion of protein or the like to the electrode, and stable measurement cannot be performed. It was.
[0008]
This conventional sugar detection device has a drawback that even when the electrode is soiled in such a manner, the enzyme film formed on the electrode is easily damaged by a mechanical action, so that it is difficult to clean. [0009]
[Problems to be solved by the invention]
An object of the present invention is to eliminate the above-described drawbacks of conventional sugar detection devices. That is, the object of the present invention is to maintain high sensitivity even when used for a long period of time, to obtain a highly stable measurement value, a sugar detection device that can be easily washed, and high sensitivity even after long-term implementation. It is to provide a sugar detection method that can be maintained and can obtain a highly stable measurement value.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a working electrode comprising a Ti / Ni alloy, a cell portion comprising a counter electrode and a reference electrode, and the working electrode by oxidation of sugar on the working electrode. A sugar detector characterized by comprising a current measuring unit for measuring a current flowing between the counter electrode and
As a preferred first aspect of the sugar detection device, the cell part is inserted into the working electrode insertion hole, a tubular cell having a working electrode insertion hole at a tip part, and one end part projects out of the tubular cell, The other part includes the linear working electrode attached to the tubular cell in a state of being accommodated in the tubular cell, and the counter electrode and the reference electrode accommodated in the tubular cell. ,
As a second aspect , the counter electrode is a container-like body having an internal space in which the working electrode and the reference electrode can be accommodated, and a sample solution introduction unit capable of introducing a sample solution into the internal space , And a processed liquid discharger capable of discharging the processed liquid from the internal space.
[0011]
According to another aspect of the present invention, there is provided a sugar detection method, wherein the sugar is detected by immersing the working electrode in a sample solution adjusted to be alkaline using the sugar detection apparatus according to the first aspect. ,
In another aspect of the invention, the sugar detection apparatus according to the second aspect is used to detect sugar by introducing the sample solution into the internal space from the sample solution introduction unit into the sample solution adjusted to be alkaline. This is a sugar detection method.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The sugar detection device according to the present invention includes a working electrode comprising a Ti / Ni alloy, a cell part having a counter electrode and a reference electrode, and the working electrode and the counter electrode by oxidation of sugar on the working electrode. And a current measuring unit for measuring a current flowing between them. This sugar detection apparatus can take various modes.
[0013]
FIG. 1 is a conceptual diagram of a sugar detection apparatus 1 which is a first aspect of the sugar detection apparatus according to the present invention. The sugar detection device 1 includes a cell unit 2 and a current measurement unit 3.
[0014]
The cell part 2 is a part that is immersed in the sample solution and generates an electric current corresponding to the sugar concentration by oxidizing the sugar in the sample solution. The cell unit 2 includes a cell 4, a working electrode 5, a counter electrode 6, a reference electrode 7, and an electrolytic solution 8.
[0015]
The cell 4 is a member that houses the working electrode 5, the counter electrode 6, the reference electrode 7, and the electrolytic solution 8, and forms the outer shell portion of the cell portion 2. The cell 4 is a tubular body, and has an insertion hole 14 into which the working electrode 5 can be inserted at the tip thereof. The size of the insertion hole 14 is determined according to the outer diameter of the working electrode 5. The cell 4 is formed of an insulating material because it is necessary to prevent current from flowing between the inside and the outside. As said insulating material, resin, such as an epoxy resin, is preferable from points, such as intensity | strength, weight, and safety | security.
[0016]
The size of the cell 4 is not particularly limited as long as sugar can be measured, and can be appropriately determined according to the purpose. For example, when the diameter of the cell 4 is about 20 mm, it is easy to use and suitable.
[0017]
The working electrode 5 is a linear body, is inserted into the insertion hole 14 of the cell 4, and is fitted into the cell 4 with one end portion in the cell 4 and the other end portion protruding outside the cell 4. Yes.
[0018]
The working electrode 5 is an electrode having a function of oxidizing sugar in the sample solution.
The working electrode 5 is made of a Ti / Ni alloy. The TiNi alloy has a function of quantitatively oxidizing OH groups of sugars in an alkaline solution. Therefore, since the material of the working electrode 5 is a TiNi alloy, the working electrode 5 can contact the sugar in the sample solution, oxidize the sugar, and generate a current corresponding to the sugar concentration.
[0019]
The composition of Ti and Ni in the TiNi alloy is not particularly limited as long as the function of the alloy is ensured. For example, the Ti content is 40 to 60% by mass, and the Ni content is 60%. It is preferable that it is ˜40 mass% in that the above functions are effectively exhibited.
[0020]
The size of the working electrode 5 is not particularly limited as long as the working electrode 5 can be brought into contact with the sugar in the sample solution to generate a current having a magnitude capable of measuring the sugar concentration. -2.0 mm and length can be 0.1-50 mm.
[0021]
The length of the portion of the working electrode 5 that protrudes outside the cell 4 generates an electric current that can measure the sugar concentration when the tip of the cell portion 2 is immersed in the sample solution. The sugar in the sample solution can be oxidized to the extent possible, and there is no particular limitation as long as there is no inconvenience in handling the cell part 2, for example, 10 mm when the outer diameter of the working electrode 5 is around 1 mm. The following conditions are preferable because the above conditions are suitably satisfied.
[0022]
The counter electrode 6 is accommodated inside the cell 4. The counter electrode 6 is a linear body, and the size of the counter electrode 6 is appropriately determined in relation to the size of the working electrode so that the measurement electricity can flow smoothly in combination with the working electrode 5.
[0023]
The material of the counter electrode 6 is not particularly limited as long as the measurement electric energy can be flowed in the combination with the working electrode 5 without any problem, and known counter electrode materials such as stainless steel such as SUS316, platinum, and carbon are used. can do.
[0024]
The reference electrode 7 is accommodated inside the cell 4. The counter electrode 6 is a linear body, and the size thereof is not particularly limited as long as the potential of the working electrode 5 can be appropriately set, and is appropriately determined according to the various conditions of the cell unit 2.
[0025]
The reference electrode 7 is not particularly limited as long as the potential of the working electrode 5 can be appropriately set, and examples thereof include known reference electrodes such as a silver-silver chloride electrode, a sweet potato electrode, and a hydrogen electrode.
[0026]
The electrolytic solution 8 is accommodated inside the cell 4. The electrolytic solution 8 has a portion of the working electrode in the cell 4, the counter electrode 6 and the reference electrode 7 immersed therein. The electrolytic solution 8 is not particularly limited as long as an electric current can be generated based on the oxidation of the sugar, and examples thereof include an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, and lithium hydroxide.
[0027]
The current measuring unit 3 is a part that measures the magnitude of the current generated in the cell unit 2 to obtain the sugar concentration. The current measuring unit 3 includes a lead wire 9, a lead wire 10, a power source 11, a power source 12, and an ammeter 13. The lead wire 9 connects the counter electrode 6 and the reference electrode 7. The lead wire 9 is provided with a power supply 11 so that the counter electrode 6 side is a cathode and the reference electrode 7 side is an anode. The lead wire 10 connects the counter electrode 6 and the working electrode 5. The lead wire 10 is provided with a power source 12 so that the counter electrode 6 side is a cathode and the working electrode 5 side is an anode. The lead wire 10 is provided with an ammeter 13.
[0028]
The sugar detection apparatus 1 operates as follows by having the above configuration.
[0029]
A sample solution containing a sugar is mixed with an alkaline solution to prepare a sample solution. The tip of the cell part 2 is immersed in the sample solution, and the part of the working electrode 5 that protrudes outside the cell 4 is immersed in the sample solution. The sugar in the sample solution contacts the working electrode. The sugar in contact with the working electrode 5 is oxidized by the action of the TiNi alloy. Then, in the periphery of the working electrode 5, oxygen is consumed by the oxidation reaction, the amount of oxygen reaching the counter electrode 6 decreases, and the oxygen reduction current in the counter electrode 6 decreases. The amount of current decrease is measured by the ammeter 13. The amount of current decrease is proportional to the sugar concentration in the sample solution. Therefore, the sugar concentration in the sample solution can be obtained based on the measured value by the ammeter 13.
[0030]
As described above, the sugar detecting device 1 can measure the sugar concentration only by immersing the portion of the working electrode 5 protruding from the cell 4 in the sample solution. Therefore, according to the sugar detection apparatus 1, continuous sugar analysis can be performed. In addition, since the sugar detection device 1 uses a sugar reaction using a TiNi alloy, there is no problem of performance deterioration over time due to the deactivation of an enzyme such as an enzyme electrode, and stable measurement can be performed over a long period of time. Is possible.
[0031]
The sample is not particularly limited as long as the sample solution can be prepared, and body fluids such as saliva, blood, and urine can also be suitably used.
[0032]
The sugar contained in the sample is not particularly limited as long as the sugar can be oxidized by a TiNi alloy. As described above, TiNi alloys oxidize OH groups to bonds to sugar carbon atoms. Examples of such sugars include monosaccharides such as glucose, fructose and mannose, disaccharides such as sucrose, maltose and lactose, and oligosaccharides and polysaccharides having three or more sugars.
[0033]
The alkaline solution used when preparing the sample solution is not particularly limited as long as it can oxidize sugar with a TiNi alloy, and examples thereof include an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution. The concentration of the alkaline solution is not particularly limited as long as the sugar oxidation reaction can be advanced. However, for example, when the concentration is 0.01 to 2.0 N, the oxidation reaction suitably proceeds and handling is easy. It is preferable in a certain point.
[0034]
As the mixing ratio of the sample and the alkaline solution when preparing the sample solution, the sample solution has ensured alkalinity necessary for the oxidation reaction and a sugar concentration capable of generating a detectable current. If it is, there will be no restriction | limiting in particular, According to the sugar concentration etc. of a sample, it can determine suitably.
[0035]
The sugar concentration in the sample solution is not particularly limited as long as a current detectable by the ammeter 13 can be generated, but is preferably 100.0 g / l or less from the viewpoint of analysis accuracy.
[0036]
As described above, the sugar detecting device 1 is an example of the sugar detecting device according to the present invention, and the sugar detecting device according to the present invention is not limited to the sugar detecting device 1 and takes various forms. Can do. For example, in the sugar detection apparatus 1, the shapes of the cell 4, the working electrode 5, the counter electrode 6, and the reference electrode 7 can be changed as appropriate.
[0037]
For example, the working electrode is not particularly limited as long as it is formed of a TiNi alloy. For example, the working electrode may be linear, spiral, columnar, or plate-shaped. The working electrode can be attached by any method as long as it can oxidize the sugar in the sample solution, and a part of the working electrode protrudes from the cell 4 as in the sugar detecting device 1. There is no limit to the method of mounting. The working electrode according to the present invention can also be used in the same manner as the working electrode in a known three-pole current measuring device.
[0038]
The structure of the current measuring unit 3 of the sugar detecting device 1 may be of any structure as long as it can measure the current generated in the cell unit 2 as described above, and a known current measuring unit is used. be able to.
[0039]
FIG. 2 is a conceptual diagram of a sugar detection device 21 which is a second aspect of the sugar detection device according to the present invention. The sugar detection device 21 includes a cell unit 22 and a current measurement unit 23. The cell portion 22 includes a resin cell 24, a working electrode 25, a counter electrode 26, and a reference electrode 27. The working electrode 25 and the reference electrode 27 are, for example, a linear body or a rod-shaped body, and the same materials as those of the working electrode 5 and the reference electrode 7 can be used, respectively. The counter electrode 26 is, for example, a plate-like body, and the same material as that of the counter electrode 6 can be used.
[0040]
The resin cell 24 accommodates a working electrode 25, a counter electrode 26 and a reference electrode 27. Further, the resin cell 24 has a sample solution introduction part 28 capable of introducing a sample solution into a space containing the working electrode 25 and the like, and a target for discharging the liquid to be treated obtained after the measurement. And a processing liquid discharger 29.
[0041]
A branch flow path 31 is connected to the sample solution introducing unit 28 via a pump 30, a sample container 32 is provided at one end thereof, and an eluent container 33 containing an alkaline solution is provided at the other end.
The material of the resin cell 24 is the same as the material of the cell 4.
[0042]
The sugar detection device 21 operates as follows. The pump 30 is driven, the sample is sucked from the sample container 32, and the alkaline solution is sucked from the eluent container 33, and these are mixed in the branch flow path 31 to obtain a sample solution. Liquid. In this internal space, the working electrode 25, the counter electrode 26, and the reference electrode 27 are in contact with the sample solution. Hereinafter, in the same manner as described above, a current based on the oxidation reaction of sugar is generated, and the current measuring unit 23 measures the current to measure the sugar concentration of the sample. The processed liquid obtained after the measurement in the resin cell 24 is discharged from the processed liquid discharge unit 29 to the outside of the resin cell 24.
[0043]
FIG. 3 is a conceptual diagram of a sugar detection device 41 which is a third aspect of the sugar detection device according to the present invention. The sugar detection device 41 includes a cell unit 42 and a current measurement unit 43. The cell part 42 includes a working electrode 45, a counter electrode 46, and a reference electrode 47. The working electrode 45 and the reference electrode 47 are, for example, a linear body or a rod-shaped body, and the same material as that of the working electrode 5 and the reference electrode 7 can be used, respectively.
[0044]
The counter electrode 46 is formed in a container shape, has an internal space 54, and accommodates the working electrode 45 and the reference electrode 47 in the internal space 54. The counter electrode 46 has a sample solution introduction unit 48 capable of introducing a sample solution into the internal space 54, and a processed liquid discharge unit 49 for discharging a processed liquid obtained after the measurement is completed. Have The material of the counter electrode 46 can be the same as the material of the counter electrode 6, for example, SUS316.
[0045]
A branch flow path 51 is connected to the sample solution introduction section 48 via a pump 50, a sample container 52 is provided at one end, and an eluent container 53 containing an alkaline solution is provided at the other end.
[0046]
The sugar detection device 41 operates as follows. The pump 50 is driven to suck the sample from the sample container 52 and the alkaline solution from the eluent container 53 and mix them in the branch flow path 51 to obtain a sample solution, which is sent to the internal space 54 of the counter electrode 46. Liquid. In the internal space 54, the working electrode 45, the counter electrode 46, and the reference electrode 47 are in contact with the sample solution. Hereinafter, in the same manner as described above, a current based on the oxidation reaction of sugar is generated, and the current measuring unit 43 measures the current, thereby measuring the sugar concentration of the sample. The processed liquid obtained after the measurement in the counter electrode 46 is discharged from the processed liquid discharge portion 49 to the outside of the counter electrode 46.
[0047]
As described above, in the sugar detection device according to the present invention, the TiNi alloy is used as the working electrode. The conventional sugar detector using an enzyme for the working electrode has a short life span of several months because it cannot avoid inactivation of the enzyme over time, but it is used as a working electrode in the sugar detector according to the present invention. Since the TiNi alloy does not deteriorate with time like an enzyme, the sugar detecting apparatus according to the present invention can be used for at least one year.
[0048]
Further, in the conventional sugar detection apparatus, the enzyme film formed on the electrode is easily damaged by a mechanical action, so that there is a disadvantage that washing is difficult. In the apparatus, since the mechanical strength of the TiNi alloy used as the working electrode is large, cleaning is easy.
[0049]
The sugar detection method according to the present invention can be performed based on the description of each sugar detection device using each sugar detection device.
[0050]
【Example】
Hereinafter, the sugar detection apparatus and the sugar detection method according to the present invention will be described in more detail with reference to examples.
[0051]
(1) Sugar detection apparatus A sugar detection apparatus having a cell part having the structure shown in FIG. 3 was used. The working electrode is made of a TiNi alloy composed of 50% by mass of Ti and 50% by mass of Ni, the diameter thereof is 1.0 mm, and the length of the portion inserted into the counter electrode is 5.0 mm. The reference electrode is a silver-silver chloride electrode.
[0052]
(2) Sample solution Glucose was dissolved in a 0.1N sodium hydroxide aqueous solution to prepare four types of glucose solutions having glucose concentrations of 5, 10, 15 and 20 g / l. Further, the aqueous sodium hydroxide solution was used as a blank solution. These five types of solutions were designated as sample solution group 1.
Albumin was dissolved in each of the five solutions of the sample solution group 1 so that the concentration thereof was 2 g / l, and five new solutions were prepared. These five types of solutions were designated as sample solution group 2.
Similarly, sample solution group 3 in which albumin was dissolved to 5 g / l and sample solution group 4 in which albumin was dissolved to 7 g / l were prepared.
[0053]
(3) Measuring method Each solution of each sample solution group was injected into the internal space of the counter electrode from the sample solution introducing portion of the counter electrode, the generated current was measured, and the integral value was obtained.
[0054]
(4) Results FIG. 4 shows a plot of the value obtained by subtracting the integrated value for the blank solution of the sample solution group from the integrated value for the glucose solution of each sample solution group against the glucose concentration. It is the obtained figure. In FIG. 4, the broken lines (1), (2), (3) and (4) indicate the results obtained from the sample solution group 1, the sample solution group 2, the sample solution group 3 and the sample solution group 4, respectively.
[0055]
As can be seen from FIG. 4, the integrated value of the current obtained by the sugar detection apparatus according to the present invention has a strong correlation with the glucose concentration. FIG. 4 also shows that this integrated value is not greatly affected by the presence of albumin. Therefore, it can be seen from the results of this example that the sugar detection device and the sugar detection method according to the present invention can be suitably applied to saliva, blood, and the like containing a large amount of protein such as albumin.
[0056]
【The invention's effect】
According to the sugar detection apparatus and the sugar detection method according to the present invention, since a TiNi alloy is used for the working electrode, high-accuracy sugar detection is possible for a long period of time, and washing is easy.
[0057]
The sugar detection device and the sugar detection method according to the present invention can be applied to any sugar that can be oxidized by a TiNi alloy. Therefore, according to the sugar detection apparatus and the sugar detection method according to the present invention, a wide range of sugars can be detected.
[0058]
Since the sugar detection apparatus and the sugar detection method according to the present invention do not have a large effect on the measurement value even if impurities such as proteins are mixed in the sample, sugar detection in saliva and blood etc. in which these impurities exist It can be suitably applied to.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a sugar detection device 1 which is a specific example of a sugar detection device according to the present invention.
FIG. 2 is a conceptual diagram of a sugar detection device 21 which is a specific example of the sugar detection device according to the present invention.
FIG. 3 is a conceptual diagram of a sugar detection device 41 which is a specific example of the sugar detection device according to the present invention.
FIG. 4 is a graph obtained by plotting a value obtained by subtracting the integral value for the blank solution of the sample solution group from the integral value for the glucose solution of each sample solution group against the glucose concentration. It is the obtained figure.
[Explanation of symbols]
1 .... sugar detector, 2 .... cell part, 3 .... current measuring part, 4 .... cell, 5 .... working electrode, 6 .... counter electrode, 7 .... reference electrode, 8 .... electrolyte, 9 ··· Lead wire, 10 ·· Lead wire, 11 ·· Power source, 12 ·· Power source, 13 ·· Ammeter, 14 ·· Insertion hole, 21 ·· Sugar detector, 22 ·· Cell part, 23 ·· Current Measurement unit 24 ··· Resin cell 24, 25 ·· Working electrode 26 ·· Counter electrode 27 ·· Reference electrode 28 · · Sample solution introduction unit · 29 · Solution discharge unit 30 · · Pump 31 ... Branch channel 32 ... Sample container 33 ... Eluent container 41 ... Sugar detector 42 ... Cell unit 43 ... Current measuring unit 45 ... Working electrode 46 ... Counter electrode 47 .. Reference electrode 48.. Sample solution introduction part 49.. Processed liquid discharge part 50.. Pump 51. Sample container 53 .. elution receptacle, 54 ... inner space

Claims (4)

A cell portion having a working electrode comprising a Ti / Ni alloy, a counter electrode and a reference electrode, and a current flowing between the working electrode and the counter electrode due to oxidation of sugar on the working electrode are measured. Ri formed and a current measuring unit,
The cell portion is a tubular cell having a working electrode insertion hole at a tip portion, and is inserted into the working electrode insertion hole, one end portion protrudes outside the tubular cell, and the other portion is accommodated in the tubular cell. A sugar detecting device comprising: the linear working electrode attached to the tubular cell; and the counter electrode and the reference electrode accommodated in the tubular cell . A cell portion having a working electrode comprising a Ti / Ni alloy, a counter electrode and a reference electrode, and a current flowing between the working electrode and the counter electrode due to oxidation of sugar on the working electrode are measured. A current measuring unit,
The counter electrode is a container-like body having an internal space in which the working electrode and the reference electrode can be accommodated, and a sample solution introduction part capable of introducing a sample solution into the internal space, and the internal space A sugar detection apparatus comprising a processed liquid discharger capable of discharging a processed liquid. A saccharide detection method comprising: detecting a saccharide by immersing the working electrode in a sample solution adjusted to be alkaline using the saccharide detection apparatus according to claim 1 . A saccharide detection method, wherein the saccharide is detected by introducing the saccharide detection apparatus according to claim 2 into the sample solution adjusted to be alkaline from the sample solution introduction section into the internal space.

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