1. Field of the Invention
The present invention relates in general to a fluid element, and more particularly to a fluid element which is useful for treatment of a micro quantity of liquid in chemical analysis devices, medical devices, biotechnology devices, and the like. In particular, the present invention relates to a fluid element which is applied to microanalysis systems (μTAS: Micro Total Analysis Systems) for effecting chemical analysis or chemical synthesis on a chip, and more particularly to a fluid element which is applied to defusement (or making harmless) of harmful substances generated in the μTAS or the like, recovery and reuse of a raw material from a waste liquid, decomposition, dissolution, reaction acceleration, and the like.
2. Related Background Art
In recent years with development of three-dimensional microprocessing techniques, the systems attracting attention are those which have fluid elements such as a fine flow path, a pump, and a valve, and a sensor integrated on a substrate such as of glass or silicon, and conduct chemical analysis on the substrate. Such a system is called a microanalysis system, a μ-TAS (Micro Total Analysis System), or Lab on a Chip. The miniaturization of the chemical analysis system enables decrease of void volume and remarkable reduction in sample amount.
The miniaturization also enables shortening of the analysis time and a decrease in power consumption of the entire system. Further, the miniaturization is promising for price reduction of the system. Furthermore, the μ-TAS is promising in medical services such as home medical care and bedside monitoring, and biotechnology such as DNA analysis and proteomics analysis because it enables the miniaturization and price reduction of a system, and a remarkable shortening in analysis time.
Japanese Patent Application Laid-open No. H10-337173 discloses a micro-reactor capable of implementing a sequence of biochemical experiment steps of mixing solutions to cause reaction, analyzing quantitatively the reaction product, and separating the product, by using combination of cells. The micro-reactor has isolated reaction chambers each closed tightly with a flat plate on a silicon substrate. This micro-reactor has a reservoir cell, a mixing cell, a reaction cell, a detection cell, and a separation cell combined with each other. By providing such a reactor in plurality on a substrate, many biochemical reactions can be allowed to proceed simultaneously concurrently. Furthermore, not only the analysis but also material synthesis such as protein synthesis can also be conducted in the cells.
On the other hand, in circumstances in which tackling environmental issues becomes essential, a waste liquid treating technique using supercritical water has been proposed as a technique enabling harmful organic substances such as dioxin to be perfectly decomposed.
There is disclosed a technique for effectively making a waste liquid harmless without increasing a quantity of heavy metal ions by utilizing a waste liquid treating method in which an aqueous waste liquid containing an organic substance capable of forming a water-soluble complex with heavy metal ions is heated together with oxygen under pressure using a container made of titanium such that the temperature becomes 375° C. or more, and the partial pressure of water becomes 230 atm or more (see Japanese Patent Application Laid-open No. H03-113858).
In addition, a technique is proposed in which a waste liquid containing tetramethylammonium hydrooxide (TMAH) is subjected to supercritical water oxidation by using oxygen or hydrogen peroxide as an oxidizer under the conditions of a reaction temperature of 550 to 650° C. and a reaction pressure of 23 to 25 MPa, thereby effectively decomposing the indecomposable TMAH contained in a waste liquid from a semiconductor manufacturing plant (see Japanese Patent Application Laid-open No. H11-221583).
In addition, a chemical decontamination waste liquid treating method is proposed in which an organic acid separated and concentrated at an anode, especially, a chelating agent is decomposed using supercritical water (see Japanese Patent Application Laid-open No. H06-201898).
Also, a method of treating an analysis waste liquid is proposed in which an analysis waste liquid and an emulsifying agent are mixed with each other to form an emulsion, and the resultant emulsion is then discomposed using supercritical water (see Japanese Patent Application Laid-open No. 2003-164750).
Currently, in the field of analysis, there is a tendency that works for analyzing harmful substances such as dioxin increase due to growing interest in the environmental issues, so that treatment of an analysis waste liquid containing harmful substances becomes an important task. However, in the conventional μTAS, the circumstance has been that any system including waste liquid treating means effective for decomposing the harmful substances has not been proposed, and hence the harmful analysis waste liquid has been difficult to dispose of. In addition, because the prior art treatment system utilizing supercritical water requires such a high temperature as 374° C. or more and such a high pressure as 22 MPa or more, the treatment system should be called a large equipment and hence is difficult to miniaturize.
On the other hand, WO 2004/009226 discloses a chemical analysis method of effecting chemical analysis and chemical synthesis using a plurality of liquids on a substrate having a flow path, a fluid element, and a detection element, in which the plurality of liquids are stirred and mixed with one another by utilizing expansion and shrinkage of bubbles. In the chemical analysis method disclosed in WO 2004/009226, bubbles are generated using a heating element. However, WO 2004/009226 does not disclose the formation of the supercritical state.