JP2004053371A - Chemical analysis method and apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chemical analysis method for concentrating a liquid sample inside an apparatus by reducing contamination due to impurities without using any concentration apparatus being separately installed outside. <P>SOLUTION: The chemical analysis method has a liquid tank, a channel, a fluid control element, and a detection element on a board, and an chemical analysis and chemical synthesis are performed on the board by using the liquid sample. Then, the liquid sample is heated by an electrical heating element and a solvent is evaporated for concentrating. The electrical heating element is provided in the liquid tank or the channel. One or entire portion of a surface for composing the liquid tank having the electrical heating element or the channel is formed by a material where a gas constituent can be permeated and a liquid constituent cannot be permeated. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a chemical analysis method and apparatus, and more particularly, to a chemical analysis method and apparatus for concentrating a liquid sample in a miniaturized analysis system (μTAS: Micro Total Analysis System) for performing chemical analysis or chemical synthesis on a chip.
[0002]
[Prior art]
In recent years, with the development of three-dimensional microfabrication technology, a system that integrates microscopic flow paths, fluid elements such as pumps and valves, and sensors on a substrate such as glass or silicon and performs chemical analysis on the substrate has attracted attention. ing. These systems are called miniaturized analysis systems, μ-TAS (Micro Total Analysis System) or Lab on a Chip. By reducing the size of the chemical analysis system, it is possible to reduce the ineffective volume and to significantly reduce the sample volume. Further, the analysis time can be reduced and the power consumption of the entire system can be reduced. Further, the system can be expected to have a low price due to the miniaturization. μ-TAS can be used in medical fields such as home medical care and bedside monitors, and in bio fields such as DNA analysis and proteome analysis, because the system can be reduced in size and cost and the analysis time can be significantly reduced. Expected.
[0003]
In chemical analysis, it may be necessary to concentrate a sample to a certain concentration as a pretreatment for analyzing the sample. For example, when analyzing a component contained in a liquid sample, if the concentration is extremely low, it is difficult to analyze the component as it is. In such a case, it is necessary to concentrate the liquid sample and increase the concentration of the component to be analyzed to a concentration at which analysis is possible. Examples of the method for concentrating a sample in chemical analysis include a method using an ion exchange resin, an organic solvent extraction method, and an evaporative concentration method. Among them, the evaporative concentration method is a method of evaporating a liquid sample containing a trace component to reduce the amount of the solvent, thereby relatively increasing the concentration of the trace component contained in the solvent. For example, JP-A-10-22251 and JP-A-2001-205031 disclose an apparatus and a method for heating and concentrating a sample as pretreatment for chemical analysis.
[0004]
Even when performing chemical analysis with μTAS, it is naturally necessary to concentrate the sample. When the sample is concentrated using the above-described conventional technique, the concentrated sample is introduced into the μTAS outside the system. In this case, the following problem occurs.
[0005]
When the enrichment operation is performed outside the system, a high-concentration sample is introduced into μTAS using a pipette or a syringe. At this time, if there is an error due to handling or the like in the amount of the liquid sample to be introduced, the influence on the amount of the analysis component is large, and an error easily occurs in final analysis data. On the other hand, when concentration is performed inside the system, a low-concentration sample may be introduced, so that the influence of the error in the introduced amount on the final analysis result is reduced, and the reliability of the analysis result is improved.
[0006]
In addition, when the concentration is performed externally and then introduced into the μTAS, the labor is complicated, the entire analysis time including the pretreatment increases, and the analysis cost may be increased. In the course of concentration and introduction into μTAS, the sample may be contaminated with impurities.
[0007]
[Problems to be solved by the invention]
From the situation described above, when performing chemical analysis involving concentration with μTAS, a system having a mechanism that plays a role of concentration inside the system is absolutely necessary.
[0008]
Therefore, an object of the present invention is to provide a chemical analysis method and apparatus capable of concentrating a sample inside a chemical analysis apparatus without using an external concentrator.
Another object of the present invention is to provide a chemical analysis method and apparatus capable of reducing contamination due to impurities in a process of concentrating a liquid sample and obtaining stable analysis data.
[0009]
[Means for Solving the Problems]
That is, the first invention of the present invention relates to a chemical analysis method having a liquid tank, a flow path, a fluid control element and a detection element on a substrate, and performing chemical analysis and chemical synthesis using a liquid sample on the substrate. And a method for concentrating the liquid sample by heating the liquid sample with a heating element to evaporate a solvent.
[0010]
A second invention of the present invention is a chemical analysis device that has a liquid tank, a flow path, a fluid control element, and a detection element on a substrate, and performs chemical analysis and chemical synthesis using a liquid sample on the substrate. A chemical analyzer comprising a concentrating means for concentrating a liquid sample by heating the liquid sample with a heating element to evaporate a solvent.
[0011]
Next, preferred embodiments of the chemical analysis method and apparatus of the present invention will be described.
Preferably, a heating element is provided in the liquid tank.
It is preferable to have a heating element in the flow path.
Preferably, the heating element is a thin-film resistor, and the thin-film resistor is disposed on a surface constituting a flow path or a liquid tank.
It is preferable that a part or the whole of a surface forming the liquid tank or the flow path having the heating element is formed of a material through which a gas component can pass and a liquid component cannot pass.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
FIG. 1 is a conceptual diagram showing an example of an embodiment of the chemical analyzer according to the present invention. FIG. 1A is a plan sectional view taken along line AA ′, and FIG. 1B is a longitudinal sectional view taken along line BB ′. Hereinafter, an embodiment of the present invention will be described with reference to FIG.
[0013]
The chemical analyzer shown in FIG. 1 includes, on a substrate 101, liquid tanks 102 to 105 for storing a liquid sample, flow paths 106 to 109 for moving the liquid sample, a heating element 110 for heating the liquid sample, and heat generation for the liquid sample. There is provided a concentrating means 115 for concentrating by heating by the body element to evaporate the solvent.
[0014]
The material of the substrate 101 is not particularly limited as long as it has resistance to the liquid sample and resistance to the heat generated by the heating element. For example, a semiconductor material such as silicon, a glass material, a metal material, a resin material, and the like can be given.
[0015]
As the liquid sample, for example, a solution using water or alcohol as a solvent can be used. Further, a solution capable of evaporating a solvent by heating using a heating element can be used as a liquid sample. Further, the chemical analyzer of the present invention can be used for biochemical reactions using biological components such as DNA and proteins, in addition to chemical reactions such as redox reactions and addition reactions.
[0016]
On the bottom surface of the liquid tank 105, a heating element 110 is formed. The heating element 110 includes a thin film resistor and electrodes (not shown) for applying a voltage to both ends of the thin film resistor.
[0017]
FIG. 5 shows a specific example of the configuration of the heating element. The heating element 501 is formed on a substrate 505, and has a configuration in which upper and lower surfaces of a thin-film resistor 503 are sandwiched between protective layers 502 of an insulator. Examples of the material of the thin film resistor 503 include a metal material and a semiconductor such as silicon having conductivity. The protective layer 502 can protect the surface of the thin film resistor from a chemical reaction. As a material of the protective layer 502, a material having high chemical resistance is preferable. For example, an insulating material such as SiO ₂ or Si ₃ N ₄ and a metal material such as Ta may be used. Further, both ends of the thin film resistor are electrically connected to the electrode 504 via contact holes formed in the protective layer 502. By applying a voltage to both ends of the thin film resistor via the electrode 504, the heating element can be heated. A heat storage layer 506 is formed between the substrate 505 and the heating element 501. By providing the heat storage layer 506, heat generated in the heating element 501 can be efficiently used for concentrating the sample without dissipating to the substrate 505 side. The material of the heat storage layer 506 is selected from materials having low thermal conductivity. For example, an insulator material such as SiO ₂ or Si ₃ N ₄ is preferable.
[0018]
The heating element 110 can be used not only for concentrating the sample, but also for heating the sample to promote a chemical reaction. Further, the heating element 110 can also be used for the purpose of heating and degassing the sample.
[0019]
Each of the liquid tanks and the flow paths are shut off from the outside air by the shut-off unit 112. The material of the blocking unit 112 is not particularly limited as long as it is resistant to the liquid sample and resistant to the heat generated by the heating element. Considering the case of observing the state of the sample from the top plate side or performing optical analysis, it is preferable to use a light transmissive material such as glass or resin.
[0020]
The upper portion of the liquid tank 105 is sealed with a sealing material 113 made of a material that allows only gas components to pass therethrough. The sealing material 113 is made of a porous film. As a material for forming the porous membrane, a hydrophobic polymer such as polypropylene, polyethylene, polytetrafluoroethylene, polysulfone, polyacrylonitrile, and cellulose acetate can be used. By using a material that allows only gas components to pass through, it is possible to remove only the gas evaporating from the liquid tank 105 to the outside of the apparatus without leaking the liquid sample to the outside. Further, as compared with the case where the upper portion of the liquid tank 105 is opened to the outside without sealing, the possibility that the inside of the system is contaminated by impurities from the outside of the apparatus can be reduced.
[0021]
A sample introduction port 114 for introducing a liquid sample into the liquid tanks 102 to 104 is formed in a portion of the blocking unit 112 corresponding to the upper part of the liquid tanks 102 to 104.
[0022]
Although not shown, the flow paths 106 to 108 for introducing a plurality of liquids from the liquid tanks 102 to 104 to the liquid tank 105 and the liquid concentrated in the liquid tank 105 are introduced from the liquid tank 105 to another tank. May be provided with a valve for controlling the flow of the liquid. By concentrating in the liquid tank 105 with all valves formed in the flow paths 106 to 109 closed, the liquid does not move to the outside of the liquid tank 105 at the time of concentration. It is possible to concentrate the liquid more efficiently than in the case where the liquid is concentrated. After the liquid is sufficiently concentrated, by opening the valve, the concentrated liquid can be sent to the reaction and analysis tank.
[0023]
Next, a method for concentrating a liquid sample in the present embodiment will be described.
First, a liquid sample is introduced from the sample inlet 114 into the liquid tanks 102 to 104. The liquid sample injected into each liquid tank is introduced into the liquid tank 105 via channels 106 to 108. When different types of liquid samples are introduced into each liquid tank, the samples come into contact with each other in the liquid tank 105 and are mixed. In this state, by heating the heating element 110, the temperature of the liquid sample in the liquid tank 105 increases, and the solvent in the liquid sample evaporates. Thereby, the concentration of the solute in the liquid sample becomes relatively high, and the liquid sample can be concentrated. The evaporated solvent permeates through the sealing material 113 and is discharged to the outside of the device.
[0024]
The liquid sample concentrated in the liquid tank 105 is sent to another part of the chemical analyzer (for example, a reaction / analysis unit) via the flow path 109.
In this embodiment, in the liquid tank 105, not only concentration but also processing such as heating and mixing can be performed.
[0025]
FIG. 2 is a conceptual diagram showing another embodiment of the chemical analyzer of the present invention. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along line CC ′. In the embodiment of FIG. 2, heating elements 209 to 211 are formed in flow paths 206 to 208 connecting the liquid tanks 202 to 204 and the liquid tank 205. In the blocking portion 212 formed on the substrate 201, portions corresponding to the heating elements 209 to 211 are sealed with a sealing material 213 that allows only gas components to pass therethrough. In the present embodiment, the liquid sample can be concentrated before the plurality of liquid samples are mixed, and only the sample that needs to be concentrated can be efficiently concentrated. Further, since the volume of each of the flow channels 206 to 208 is smaller than that of the liquid tank 205, the temperature of the liquid sample can be increased in a short time.
[0026]
Note that the same effects as in the present embodiment can also be obtained when the heating elements are formed in the liquid tanks 202 to 204.
[0027]
Further, the driving voltage supplied to the heating element can be pulsed, and its frequency or pulse width can be controlled. Thereby, the degree of concentration of the solvent can be set to a desired size.
[0028]
FIG. 4 is a schematic diagram showing an example of the chemical analyzer of the present invention.
The chemical analyzer according to the present invention includes a substrate 401, a sample injection tank (liquid tank) 402-404, a flow path 405, a liquid tank 406, a separation unit 407, a valve 408-410 as a fluid element, a pump 411, and a detection unit 412. Become. A heating element 413 is formed on the bottom surface of the liquid tank 406. In the chemical analyzer of FIG. 4, for example, a sample to be analyzed is introduced from a sample injection tank 402, and a mobile phase (carrier phase) is introduced from a sample injection tank 403. The mobile phase and the flow rate of the carrier layer may be adjusted by opening and closing the valves 408 and 409. The introduced mobile phase and carrier phase are mixed in the liquid tank 406. Further, by driving the heating element 413 to heat the mixed solution, a part of the solvent is evaporated and concentrated. The mixed and concentrated liquid is sent to the separation unit 407 by the pump 411, where it is separated for each component. Examples of the separation method include a liquid chromatography method and an electrophoresis method. The sample separated for each component is detected by the detection unit 412. Examples of the detection method include electrochemical detection and detection using fluorescence. The detected sample is discharged out of the substrate as a waste liquid. In FIG. 4, for convenience of explanation, a shut-off unit for shutting off the system from the outside air is omitted.
[0029]
【Example】
Hereinafter, the present invention will be described in more detail with reference to Examples. Note that the dimensions, shapes, materials, and manufacturing process conditions in the examples are merely examples, and can be arbitrarily changed as design items within a range satisfying the requirements of the present invention.
[0030]
Example 1
In this example, the chemical analyzer shown in FIG. 1 was manufactured, and a chemical analysis was performed using the manufactured chemical analyzer.
A method for manufacturing the chemical analyzer according to this embodiment will be described. FIG. 3 is a process diagram showing a manufacturing process of the chemical analyzer of the present embodiment.
[0031]
First, an SiO ₂ film 302 was formed to a thickness of 1.0 μm on a silicon substrate (25 mm long, 30 mm wide) by thermal oxidation. The SiO ₂ film 302 serves as a heat storage layer that prevents heat generated by the heating element 303 from dissipating to the substrate 301 and effectively utilizes heat generated by the heating element 303 to concentrate the liquid sample. . On the SiO ₂ film 302, a heating element 303 composed of a thin film resistor and an electrode (not shown) for applying a pulse voltage to the thin film resistor was formed. Polycrystalline silicon doped with P (phosphorus) ions and made conductive was used as the material of the thin film resistor. The surface of the thin-film resistor was covered with a SiN film (not shown) as a protective layer (FIG. 3A).
[0032]
Next, a silicon substrate 308 in which through holes serving as liquid tanks 304 and 305 and grooves serving as flow paths 306 and 307 are formed by dry etching, and a silicon substrate 301 on which a heating element 303 is formed, They were bonded using an epoxy adhesive. At this time, the positioning was performed such that the heating element 303 was disposed in the liquid tank 305 (FIG. 3B).
[0033]
Next, the glass substrate 311 in which the sample inlet 309 and the opening 310 for allowing the evaporated solvent to escape to the outside were formed by etching was bonded to the silicon substrate 308 by anodic bonding. At this time, positioning was performed such that the sample injection port 309 was located above the liquid tank 304 and the opening was located above the liquid tank 305 (FIG. 3C).
Next, the opening 310 was sealed with a sealing portion 312 made of a porous polypropylene flat membrane (FIG. 3D).
Through the above manufacturing steps, the chemical analyzer of this example was completed.
[0034]
The following concentration treatment and analysis were performed using the chemical analysis system of FIG.
First, a dichloroacetic acid-degrading bacterium, Renobacter sp. AC strain (Accession No .: FERM P-14641, described in Japanese Patent Application Laid-Open No. 8-140665), which is an independent administrative agency of the National Institute of Advanced Industrial Science and Technology, is placed in a medium having the following composition. The cells were cultured at 48 ° C. for 48 hours and proliferated.
[0035]
_{2.7g Na 2 HPO 4 · 2H 2} O
1.4 g KH ₂ PO ₄
0.5 g (NH ₄ ) ₂ SO ₄
0.2g MgSO ₄ · _7H 2 O
1mg FeSO ₄ · _7H 2 O
0.1 g sodium pyruvate (per liter of distilled water; mixed and sterilized after dissolution)
[0036]
After the growth, the cells were collected by centrifugation, and resuspended in a solution having the following composition (hereinafter referred to as solution A) so as to be 3 mL per 1 g of the cell weight.
[0037]
Solution A: a solution obtained by adding both ethylenediaminetetraacetic acid and β-mercaptoethanol to a 50 mM glycine / NaOH (pH 9.0) solution to a final concentration of 5 mM.
Next, the suspension was subjected to a French press treatment to crush the cells, and then centrifuged to collect a cell extract containing dehalogenase as a supernatant. This solution is referred to as solution B.
Next, a solution was prepared by dissolving the dichloroacetic acid solution in solution A. This solution is referred to as solution C.
[0039]
The solution B was injected into the liquid tank 102 and the solution C was injected into the liquid tank 103. The solution B and the solution C reached and contacted the liquid tank 105 via the flow path 106 and the flow path 107, respectively. In the liquid tank 105, solution C: solution B were mixed at a ratio of 19: 1, and an enzymatic decomposition reaction of dichloroacetic acid was performed at 30 ° C. for 5 hours.
[0040]
Next, the reaction solution is heated at 100 ° C. for about 30 seconds in the heating element 303 to deactivate the dehalogenase, and then further heated in the heating element 303 to reduce the amount of the reaction solution at 60 ° C. to 1/5 of the initial amount. And concentrated to.
[0041]
The solution obtained above was sent to an analysis unit (not shown) via a flow path 109. In the analysis section, the solution was filtered with a filter. Furthermore, residual dichloroacetic acid was measured by a high performance liquid chromatography (HPLC) method equipped with an ion-exchange resin packed column (developing solvent: 0.01 N sulfuric acid aqueous solution / acetonitrile = 95/5, detecting absorbance at 210 nm). Further, the generated chloride ions were measured by an electrode method. As a result, the concentration of residual dichloroacetic acid was 10.8 × 10 ⁻³ mol / l, and the concentration of produced chloride ions was 79.0 mM (converted from ppm).
[0042]
In this example, a low-concentration liquid sample was introduced into a chemical analyzer (μTAS), and after performing concentration processing in the apparatus, analysis was performed. As a result, the influence of an error in the amount introduced due to handling or the like can be reduced, and stable analysis data can be obtained. Further, the possibility of contamination by impurities in the process of concentration could be reduced.
[0043]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a chemical analysis method and apparatus capable of concentrating a sample inside a device without using a separately provided concentrator.
Further, the present invention can provide a chemical analysis method and apparatus capable of reducing contamination due to impurities in a process of concentrating a liquid sample and obtaining stable analysis data.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an example of an embodiment of a chemical analyzer according to the present invention.
FIG. 2 is a conceptual diagram showing another embodiment of the chemical analyzer of the present invention.
FIG. 3 is a process chart showing a method for producing a chemical analysis device of the present invention.
FIG. 4 is a schematic view showing an example of the chemical analyzer of the present invention.
FIG. 5 is a schematic diagram showing a configuration of a heating element.
[Explanation of symbols]
101, 201, 401, 505 Substrates 102 to 105, 202 to 205, 304 to 305, 406 Liquid tanks 106 to 109, 206 to 208, 306 to 307, 405 Flow paths 110, 209 to 211, 303, 413, 501 Body element 111, 506 Heat storage layer 112, 212 Blocking part 113, 213 Sealant 114, 309 Sample injection port 115 Concentrator 301, 308 Silicon substrate 302 SiO ₂ film (heat storage layer)
310 Opening 311 Glass substrate (blocking part)
402-404 Sample injection tank (liquid tank)
407 Separation sections 408 to 410 Valve 411 Pump 412 Detection section 502 Protective layer 503 Thin film resistor 504 Electrode

Claims (14)

In a chemical analysis method having a liquid tank, a flow path, a fluid control element, and a detection element on a substrate and performing chemical analysis and chemical synthesis using a liquid sample on the substrate, the liquid sample is heated by a heating element. A chemical analysis method characterized in that the solvent is concentrated by evaporating the solvent. The method according to claim 1, wherein a heating element is provided in the liquid tank. 3. The chemical analysis method according to claim 1, wherein the concentration is performed in the liquid tank with all valves formed in the flow path closed. 3. The chemical analysis method according to claim 1, wherein a heating element is provided in the flow path. 5. The chemical according to claim 1, wherein the heating element is a thin-film resistor, and the thin-film resistor is disposed on a surface forming a flow path or a liquid tank. 6. Analysis method. The liquid tank having the heating element or a part or all of a surface constituting a flow path is formed of a material through which a gas component can pass and a liquid component cannot pass. 5. The chemical analysis method according to any one of the above items 5. 7. The method according to claim 1, wherein the driving voltage supplied to the heating element is pulsed, and the frequency of the driving voltage is controlled to make the degree of concentration of the solvent a desired value. Chemical analysis method. 7. The method according to claim 1, wherein the driving voltage supplied to the heating element is pulsed, and the degree of concentration of the solvent is adjusted to a desired level by controlling the pulse width. Chemical analysis method as described. In a chemical analyzer having a liquid tank, a flow path, a fluid control element, and a detection element on a substrate and performing chemical analysis and chemical synthesis using a liquid sample on the substrate, the liquid sample is heated by a heating element. A chemical analyzer comprising a concentrating means for concentrating by evaporating a solvent by heating. The chemical analyzer according to claim 9, further comprising a heating element in the liquid tank. A flow path for introducing a plurality of liquids into the liquid tank, and a flow path for introducing a liquid concentrated in the liquid tank from the liquid tank to another tank, and controlling a flow of the liquid in the flow path The chemical analyzer according to claim 9, further comprising a valve for performing the operation. The chemical analyzer according to claim 9, further comprising a heating element in the flow path. 13. The chemical according to claim 9, wherein the heating element is a thin-film resistor, and the thin-film resistor is arranged on a surface constituting a flow path or a liquid tank. Analysis equipment. 10. A liquid tank having the heating element or a part or all of a surface constituting a flow path is formed of a material through which a gas component can pass and a liquid component cannot pass. 14. The chemical analyzer according to any one of the above items 13.

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