JPWO2001077691A1 - chemical analyzer - Google Patents

Abstract

(57) [Abstract] A chemical analyzer is provided with a sound wave generating mechanism at a position facing the outer side and bottom of a reaction vessel at a reagent supply position where a reagent is supplied into the reaction vessel, and a driver is provided for controlling the irradiation of sound waves so that, during the supply of the reagent, a component faces the liquid surface of the liquid to be measured in the reaction vessel and a component is incident obliquely or parallel to the liquid surface. This configuration enables efficient non-contact mixing and stirring, and also makes it possible to miniaturize the device.

Description

Detailed Description of the Invention

TECHNICAL FIELD The present invention relates to a chemical analyzer, and more particularly to an agitator for mixing a sample and a reagent in a reaction vessel. BACKGROUND ART The chemical analyzer described in U.S. Pat. No. 4,451,433 includes an automatic sample dispensing mechanism for supplying the sample to be analyzed and the reagent to the reaction vessel,
An automatic reagent dispensing mechanism, an automatic stirring mechanism for stirring the sample and reagent in the reaction vessel, a measuring instrument for measuring the physical properties of the sample during or after the reaction has finished, an automatic cleaning mechanism for aspirating and discharging the sample after the measurement has finished and cleaning the reaction vessel,
The system is comprised of a control mechanism for controlling these operations. In particular, the automatic mixing mechanism described above uses a spatula or screw that automatically lowers below the liquid surface to mix the sample and reagent, and then drives a motor connected to the base of the spatula to rotate the spatula to mix. Japanese Patent Application Laid-Open No. 8-146007 describes a method for non-contact mixing of the sample and reagent without using a spatula or screw, using acoustic streaming generated by irradiating the liquid with ultrasound. In recent years, medical testing centers and other facilities have been demanding high-precision, high-speed chemical analyzers that can analyze multiple collected samples simultaneously in a shorter time. This shortens the time from test to test results, allowing doctors to provide timely and appropriate treatment to patients. Furthermore, the ability to perform tests using less liquid than conventional methods is essential for future chemical analyzers, in order to reduce the amount of sample collected from patients and reduce the burden on patients, and to reduce the amount of waste liquid that must be disposed of after testing. Moreover, by overcoming the above-mentioned problems, the amount of reagent used can be reduced, which has the secondary benefit of reducing the running costs of the test. Furthermore, various other devices are being introduced into medical facilities where such chemical analysis devices are installed, and due to space constraints for installing the devices, it is also important to avoid increasing the size of the device when overcoming the above-mentioned problems. In the first prior art described above, a pipetter equipped with a robotic arm automatically dispenses sample and reagent into each reaction vessel stored on the circumference of a turntable, and a spatula stirring mechanism similarly equipped with a robotic arm automatically immerses a spatula in the liquid to be measured (the sample and reagent dispensed into the reaction vessel) to stir and mix them. Then,
The biochemical reaction is measured and the test result is output. After the measurement is completed, the liquid to be measured is aspirated and
After the reaction vessel is cleaned, one test item for that sample is completed. In actual use, multiple tests are batch-processed according to a sequence preprogrammed by the user. To achieve higher speeds in currently mainstream chemical analyzers, the time allocated to each operation (dispensing samples and reagents, stirring, and cleaning) must be shortened. Among the operations requiring time reduction, the stirring operation of the test solution is particularly problematic. Shortening the stirring time can result in insufficient mixing, leading to inaccurate test results. Furthermore, because the spatula is quickly inserted and removed from the reaction vessel, some of the test solution adhering to the spatula is scattered outside the reaction vessel. Furthermore, even though the spatula is cleaned after each stirring operation, the test solution carried over (carryover) to the reaction vessel for the next test, causing contamination. Furthermore, the spatula also carries the test solution away from the reaction vessel. Therefore, when testing with a small amount of liquid, the ratio of the amount of reaction solution to the amount of removed solution becomes large, resulting in a significant error in the analysis. The non-contact stirring method using ultrasonic waves in the second prior art solves the problem of contamination between each test sample. This stirring method stirs the object without contacting it at all, so no liquid adheres to the object, and the problem of adhesion to the spatula is solved. In this stirring method, sound waves are irradiated from the outside of the reaction vessel,
The basic principle is to induce acoustic streaming by providing an appropriate sound field intensity distribution to the material being stirred in a reaction vessel. However, as the volume of reaction liquid becomes smaller, the reaction vessel itself becomes smaller, and the surface area of the reaction vessel also becomes smaller. This makes it difficult to provide the acoustic energy necessary to generate acoustic streaming. Furthermore, to generate a circulating flow effective for stirring using acoustic streaming, a sharp intensity distribution of the sound field must be formed inside the vessel. However, as the vessel becomes smaller, the relative intensity difference of the sound field within the vessel becomes smaller, making it difficult to achieve efficient stirring in a short period of time. Disclosure of the Invention The first object of the present invention is to enable carryover-free stirring of minute liquid volumes in a chemical analysis device, thereby achieving faster analytical processing capabilities. The second object of the present invention is to enable carryover-free stirring of minute liquid volumes in a chemical analysis device, thereby further miniaturizing the device. The above-mentioned objects can be achieved by providing a sound wave generating means outside the reaction vessel, and by irradiating the sound wave parallel to or obliquely to the liquid surface of the liquid to be measured inside the reaction vessel in a direction from the liquid phase toward the gas phase, and by setting the sound wave generating means at the same position as the reagent supply means supplies the reagent to the reaction vessel, so that stirring is performed simultaneously with the reagent supply. BEST MODE FOR CARRYING OUT THE INVENTION One embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a perspective view showing the configuration of the chemical analysis apparatus of this embodiment. Figure 2 is a longitudinal sectional view showing the configuration of a non-invasive (non-contact) stirring device equipped in the chemical analysis apparatus shown in Figure 1, which stirs and mixes the object to be stirred without contact. This chemical analysis apparatus comprises a reaction disk 101 that stores reaction vessels 102, a thermostatic chamber 114 for maintaining a constant temperature of the liquid to be detected and the like in the reaction vessels 102 stored on the reaction disk 101, a sample turntable 103 that stores sample cups 104, a reagent turntable 106 that stores reagent bottles 105, a sampling and dispensing mechanism 107 that dispenses samples and reagents into the reaction vessels, a reagent dispensing mechanism 108, a stirring mechanism 109 that stirs the dispensed sample and reagent in the reaction vessels, a photometry mechanism 110 that measures the reaction process of the mixed substance in the reaction vessel and the absorbance after the reaction, and a cleaning mechanism 111 that cleans the reaction vessels after the test (photometry) is completed.
In this embodiment, the mechanisms for dispensing and stirring the reagent are arranged so that they can be performed simultaneously at the same position. The above components are configured by the user through the console 113 before starting the test.
The main controller 112 automatically generates and operates the stirring mechanism 109 based on the information (analysis items, volume of liquid to be analyzed) set in the stirring mechanism 109. As shown in FIG. 2, the stirring mechanism 109 is composed of two sound sources, a downward sound source 205 and a side sound source 206, mounted on the inner wall of the thermostatic chamber housing the reaction vessels. Each sound source is configured with an array of segments that can be driven independently. A driver 207 selects and drives the appropriate segment, enabling sound waves to be emitted to the target location. In the present invention, the test solution 202 is stirred using sound waves, and the stirring mechanism is composed of a sound wave generating means. In this embodiment, the sound emitted from the sound source is transmitted to the reaction vessels via the constant-temperature water in the thermostatic chamber. Next, an overview of the operation of the entire apparatus based on the above configuration will be described, followed by a detailed description of the operation of the stirring mechanism in this embodiment. In the following explanation, to concretely explain the operation, we will use as an example a chemical analysis apparatus having 32 reaction vessels on a reaction disk. 5(a) is a diagram showing the sample dispensing position 501, the reagent dispensing position and stirring position 502, and the positions where photometry 503 and cleaning 504 are performed for 32 reaction vessels housed on the reaction disk in this embodiment. First, a sample aspirated by the sampling mechanism 107 from the sample cup 104 is dispensed into a reaction vessel stopped at the sample dispensing position 501.
Next, the reagent dispenser 10 rotates nine pitches as indicated by the arrow 505 to the position 502 where the reagent is dispensed and stirred, and then stops (hereinafter, the rotation angle for one reaction vessel is referred to as one pitch). During this stop period, the reagent dispenser 10 dispenses reagent from the reagent bottle into the reaction vessel.
The reagent aspirated by the reaction disk 8 is dispensed. At the same time as dispensing, stirring is performed by a stirring mechanism, which will be described in detail later. Furthermore, the reaction disk rotates 24 pitches as indicated by arrow 506 while crossing the photometric mechanism 503, and stops at position 509, one pitch ahead of the previous dispensed position. The above rotation and stopping operations from sample dispensing to this point constitute one cycle. When one cycle is completed, the next reaction container is stopped at the sample dispensing position, and similar operations are repeated thereafter. During one cycle, position 507, which crosses the photometric mechanism,
The absorbance of the test liquid in the reaction vessel is measured, and the change in absorbance (reaction process) is measured for each cycle. In this manner, in this embodiment, the reaction vessel rotates counterclockwise by one pitch for each cycle. When the reaction vessel into which the reagent was first dispensed reaches the position where the cleaning mechanism 504 is installed, the measurement of the absorbance change is terminated, the test liquid (hereafter referred to as waste liquid) is aspirated, and cleaning of the reaction vessel begins. Next, the stirring means and its mechanism in this embodiment will be described with reference to Figures 2 and 3. Figure 3 is an explanatory diagram of the state of the test liquid when stirring is performed simultaneously with reagent dispensing. Drivers 207 for the side sound source 205 and the downward sound source 206, connected to the main controller 112 that controls the entire device, receive information 204 regarding the volume of the liquid to be stirred, i.e., the volume of the sample being dispensed and the volume of the reagent to be dispensed. First, the driver 207 calculates the rise 304 in the liquid level of the liquid to be measured as it fills the reaction vessel from information about the liquid volume, and determines the optimum sound wave irradiation area including the liquid level position for the side and lower sound sources. Then, the sound source segment corresponding to the side irradiation area is selected and driven as indicated by arrow 303 so as to follow the rise 304 in the liquid level. At this time, the sound wave intensity on the lower side is driven to have an intensity distribution that is sufficient to raise the liquid level on one side, as shown by the liquid level 209 in Figure 2. In other words, by driving the sound wave intensity on one side of the lower array sound source to be increased, it is possible to raise the liquid level on one side. On the other hand, the sound wave intensity on the side is set to be greater than or equal to the sound wave intensity on the lower side,
The liquid surface is irradiated so as to flow toward the opposing wall of the reaction vessel.
A swirling flow as shown by arrow 210 or 306 occurs in the liquid to be measured in the reaction vessel. This flow mixes the sample and the reagent. The above-mentioned stirring operation is performed in each cycle for each reaction vessel stopped at the reagent dispensing and stirring position. Next, the configuration of the sound source used in this embodiment will be explained using FIG. 4. When a piezoelectric element is used as the sound source, as shown in FIG. 4(a), the electrode 401 on one side
is divided, and the opposing electrode 405 on the opposite side is configured as a single electrode over the entire opposite side.
At this time, a part of the counter electrode 405 is bent toward one of the electrode surfaces. By bending the electrode in this way, the connection with the power supply line is concentrated on one surface, making wiring easier. Incidentally, as shown in FIG. 4(b), the electrode 40 corresponding to the desired irradiation area 402 is
By selectively applying voltage 404 to the electrodes 3, the device becomes functionally equivalent to a sound source arranged in an array. In this embodiment, the use of a single piezoelectric element with electrodes arranged in this manner reduces the cost of the stirring mechanism. A sound source with this configuration is extremely advantageous for mass production, and manufacturing time can be shortened by forming the electrode pattern using screen printing or other methods. The principle of stirring and mixing in this embodiment differs from conventional methods that irradiate sound waves from outside the reaction vessel, imparting an appropriate sound field intensity distribution to the liquid being measured within the reaction vessel, thereby inducing acoustic flow. In other words, in this embodiment, the sound source is operated to concentrate the sound near the gas-liquid interface, utilizing flow caused by acoustic radiation pressure near the gas-liquid interface, which is completely unaffected by wall friction. Therefore, the liquid being measured can be stirred and mixed with a lower sound wave intensity than methods that utilize acoustic flow. Furthermore, in this embodiment, the nozzle 301 of the reagent dispensing mechanism is arranged as shown in Figure 3, and the ultrasonic waves are generated simultaneously with the reagent dispensing 302. Therefore, arrow 3
50. This promotes the swirling flow 306, resulting in more efficient mixing than in the case of swirling flow caused by ultrasound alone. This allows for a reduction in the allocated time for the sequence, as the device speeds up, i.e., it is possible to shorten the mixing time without reducing the mixing performance. In conventional chemical analyzers, as mentioned above, the reagent pipetter and the stirring spatula are both attached to the robot arm, and the dispensing and stirring operations are performed through the opening at the top of the reaction vessel, which causes interference with the robot arm and makes it impossible to perform these operations simultaneously. Therefore, in conventional chemical analyzers, an additional stop period is necessarily provided in one cycle, as shown in Figure 5(b). That is, the reagent dispensing position 502
In the conventional method, the reaction disk is stopped at a predetermined position, then rotated one pitch as indicated by arrow 508, stopped, and stirred at that position. However, in this embodiment, as described above, the stirring mechanism uses a sound wave generating means external to the reaction vessel, allowing both dispensing and stirring to be performed simultaneously. This improves mixing efficiency and shortens the cycle time of the device. Furthermore, if the analytical processing speed is set to the same level as conventional methods, i.e., the cycle time is set to the same level as conventional chemical analyzers, the stirring (and reagent dispensing) time can be extended, allowing for sufficient mixing. Mixing is essentially an auxiliary operation that promotes chemical reactions between multiple substances (in this embodiment, the sample and reagent) and should be performed promptly once both are dispensed into the reaction vessel. In this embodiment, stirring and mixing are performed simultaneously with reagent dispensing, so the timing of mixing is ideal compared to conventional chemical analyzers. Figure 6 is a longitudinal cross-sectional view of the reaction disk housing the thermostatic chamber and reaction vessels at the stirring mechanism position. The reaction disk 101 is connected to a motor 602 via a rotating shaft 601. The reaction disk 101 is then rotated and stopped according to the above sequence. Depending on the overall design of the chemical analyzer, it is relatively easy to secure space in the space 603 inside the thermostatic chamber (between the thermostatic chamber and the rotating shaft). In this embodiment, as shown in Figure 6, a sound wave generating means is provided on the inner wall of the thermostatic chamber, and the wiring leading to the outside is resin-molded to prevent leakage of the hot water in the thermostatic chamber. By designing the entire apparatus so that this sound wave generating means is located in the inner space rather than on the wall, it is possible to reduce the overall space required for the apparatus. A feature of the present invention is that a sound wave generating means is provided outside the reaction vessel, allowing for simultaneous stirring and reagent dispensing. This enables the chemical analyzer to achieve a high processing speed. Note that sufficient benefits can be obtained simply by replacing the conventional spatula-type stirring mechanism with the sound wave stirring mechanism shown in Figure 2. As described above, the stirring mechanism of the present invention is completely non-contact with the test solution to be mixed, completely eliminating the above-mentioned problems associated with spatula adhesion. Therefore, in chemical analysis devices where high speed is not particularly required, a contamination-free chemical analysis device can be realized by using this stirring mechanism instead of a conventional spatula stirring mechanism. Furthermore, as described above, the stirring mechanism itself is simple, so it is more reliable than conventional chemical analysis devices and the entire chemical analysis device can be made smaller. The embodiments described so far are examples of stirring mechanisms with no moving parts, emphasizing high reliability and simplicity. A feature of this is that the sound sources are arrayed and the sound source unit to be used can be selected. As another embodiment, an embodiment in which the sound source unit is movable will be described.
Figure 7 shows a configuration for stirring using a movable sound source. In the embodiment of Figure 7, instead of using an array sound source, position adjustment mechanisms 702 and 705 are provided for sound sources 703 and 706. As in the embodiment of Figure 2, the main controller 112 sends information 204 regarding the amount of liquid to be stirred and the timing of stirring to the driver 701. Based on the received information, the driver 701 determines the sound wave irradiation position according to the height of the liquid surface 209 and controls the position adjustment mechanisms 702 and 705 to move the sound source unit to the irradiation position. Next, sound waves 704 are irradiated according to the stirring timing information. As a result, a swirling flow 708 is generated, resulting in mixing. Note that in this embodiment, the position adjustment mechanism 705 of the lower sound source is designed to move vertically, but cannot move horizontally. Therefore, the sound source unit is pre-positioned to one side of the reaction vessel. The position adjustment mechanism 702 of the side sound source is designed to be movable vertically and forward and backward. In the previous examples, the reaction vessel was immersed in constant-temperature water 211 filled in a thermostatic bath to maintain a constant temperature. The sound wave generating means in the present invention generates sound waves at a frequency of several MHz, which can propagate well in water. Therefore, even a sound wave generated by a sound generating means located outside the reaction vessel can reach the interior of the reaction vessel. In contrast, in a chemical analyzer using an air thermostatic bath, which controls temperature with air rather than thermostatic water, providing a sound generating mechanism outside the reaction vessel makes sound wave propagation difficult due to the air layer between the sound generating mechanism and the reaction vessel. However, even in an air thermostatic bath, sound waves can be propagated by connecting the sound generating means and the reaction vessel with a sound transmission mechanism (such as an acoustic coupler) made of a material with an acoustic impedance similar to that of water. An example of this is described below. Figure 8 shows a cross-sectional view of the stirring section of an air thermostatic bath-type chemical analyzer. In this embodiment, sound sources 802 and 805 equipped with acoustic couplers 803 and 810 are equipped with two-axis (sound wave propagation direction and perpendicular direction) position adjustment mechanisms 801 and 804. Other configurations are the same as those in the embodiment shown in Figure 7. The driver moves the acoustic couplers 803 and 810 so that they contact the reaction vessel. The lower sound source unit is only movable vertically, so it is pre-positioned off-center from the center of the reaction vessel. Needless to say, the acoustic couplers are retracted to avoid contact with the reaction vessel while the reaction vessel is moving. In this way, the position of the sound source unit is adjusted to ensure an acoustic transmission path between the sound source and the reaction vessel. Next, by generating sound waves according to stirring timing information, it is possible to generate a swirling flow 706 similar to the previous embodiments, even in the case of an air-type thermostatic chamber, and achieve mixing. Next, as another embodiment, we will describe the case where this stirring mechanism is added to the dispensing position as an auxiliary stirring mechanism in another location. Figure 9 shows the configuration when an auxiliary stirring mechanism is provided. Figure 9(a) is an example in which two stirring mechanisms 901, 902 are provided in addition to the position for simultaneous stirring and reagent dispensing in the embodiment shown in Figure 6(a). The operation of one cycle is the same as that of the embodiment shown in Figure 6(a), and during the stop period after one cycle and after two cycles, that is, when the next reaction vessel or the reaction vessels after that are dispensing and stirring reagents, the auxiliary stirring mechanism performs additional stirring. In such an auxiliary stirring mechanism, the piezoelectric element used as the sound source is replaced with a piezoelectric element as shown in Figure 9(a).
9(b) shows a piezoelectric element that is fitted to the curvature of the thermostatic chamber to be mounted, and is placed at positions 502, 901, and 902 of the reaction vessel.
9(b) is provided with divided electrodes corresponding to the piezoelectric element 2. The piezoelectric element shown in Fig. 9(b) can be manufactured using almost the same process as the piezoelectric element shown in Fig. 4. By using an acoustic generator with this configuration, it is possible to easily add a stirring mechanism.
Also, while Figure 9(b) shows an example of a side sound source, a downward sound source can also be easily produced by similarly processing electrodes on a single piezoelectric element at positions corresponding to the positions of each reaction vessel. By providing an auxiliary stirring mechanism as in this configuration, sufficient stirring can be easily performed even when using highly viscous samples or reagents that are highly viscous and difficult to mix. In this embodiment, a two-stage stirring mechanism is added as an auxiliary mechanism, but it is easy to add more as needed. As explained above, according to the present invention, it is possible to stir a small amount of liquid without carryover, and to achieve faster analytical processing capabilities. In addition, it is possible to stir a small amount of liquid without carryover, and to further miniaturize the entire device. Industrial Applicability As described above, the present invention relates to a mechanism for stirring and mixing liquids without contact,
Although the application of the present invention to a chemical analysis device has been described in particular, it can also be applied to other devices that mix liquids etc. without contact.

[Brief explanation of the drawings]

FIG. 1 is a perspective view showing the overall configuration of a chemical analysis apparatus according to an embodiment of the present invention;
FIG. 2 is a vertical cross-sectional view showing the details of the embodiment shown in FIG. 1, and FIG.
FIG. 4 is an explanatory diagram of a case where stirring is performed simultaneously with reagent discharge, FIG. 5 is an explanatory diagram of a specific embodiment of the array sound source, FIG. 6 is a longitudinal sectional view of a thermostatic bath including a stirring mechanism of a chemical analyzer according to an embodiment of the present invention, FIG. 7 is a longitudinal sectional view showing details of a portion of a chemical analyzer according to another embodiment of the present invention, FIG. 8 is a longitudinal sectional view showing details of a portion of a chemical analyzer according to another embodiment of the present invention using an acoustic coupler, and FIG.
The figure is a diagram illustrating a chemical analysis apparatus according to another embodiment of the present invention, which incorporates auxiliary stirring.

───────────────────────────────────────────────────── Continued from the front page (72) Inventor: Katsuhiro Kanbara 882 Ichige, Hitachinaka City, Ibaraki Prefecture, Japan Measuring Instruments Group, Hitachi, Ltd. (72) Inventor: Shigenori Watari 882 Ichige, Hitachinaka City, Ibaraki Prefecture, Japan Measuring Instruments Group, Hitachi, Ltd. (72) Inventor: Hiroyasu Uchida 882 Ichige, Hitachinaka City, Ibaraki Prefecture, Japan Measuring Instruments Group, Hitachi, Ltd. (72) Inventor: Yoichiro Suzuki 882 Ichige, Hitachinaka City, Ibaraki Prefecture, Japan Measuring Instruments Group, Hitachi, Ltd. (Note) This publication is based on the publication published internationally by the International Bureau of International Patent Office (WIPO). Please note that the effect of the international publication of the Japanese-language patent application (Japanese-language utility model registration application) related to this publication arises pursuant to Article 184-10, Paragraph 1 of the Patent Act (Article 48-13, Paragraph 2 of the Utility Model Act), and is unrelated to this publication.

Claims (9)

[Claims] [Claim 1] A chemical analysis apparatus comprising a reaction vessel having an opening, a sample supply means for supplying a sample and a reagent or a diluent from said opening, a reagent supply means, a diluent supply means, and a measuring means for measuring the physical properties of said measured liquid during or after a reaction, characterized in that the chemical analysis apparatus is provided with a sound wave generating mechanism located outside said reaction vessel that irradiates sound waves parallel to or obliquely to the liquid surface of the measured liquid inside said reaction vessel in a direction from the liquid phase toward the gas phase, and at a position where a reagent is supplied to said reaction vessel, sound waves are generated to stir and mix the reagent when it is supplied. [Claim 2] A chemical analysis apparatus comprising a reaction vessel having an opening, a sample supply means for supplying a sample and a reagent or a diluent from said opening, a reagent supply means, a diluent supply means, and a measuring means for measuring the physical properties of said test liquid during or after a reaction, characterized in that a sound wave generating mechanism is provided outside said reaction vessel and irradiates sound waves sequentially to the gas-liquid interface at the liquid surface of the test liquid inside said reaction vessel and to the reaction vessel wall, and at the reagent supply position, sound waves are generated when the reagent is supplied to stir and mix the liquid. [Claim 3] A chemical analysis apparatus comprising a reaction vessel having an opening, a sample supply means for supplying a sample and a reagent or a diluent from the opening, a reagent supply means, a diluent supply means, and a measurement means for measuring the physical properties of the liquid to be measured during or after a reaction has completed, characterized in that the chemical analysis apparatus is provided with a sound wave generating mechanism located outside the reaction vessel for irradiating sound waves parallel to or obliquely to the liquid surface of the liquid to be measured inside the reaction vessel in a direction from the liquid phase toward the gas phase, and performs stirring at least twice during and after reagent supply. [Claim 4] A chemical analysis apparatus described in any one of claims 1 to 3, characterized in that the sound wave generating mechanism is arranged opposite the side or bottom surface of the reaction vessel and emits sound waves obliquely from the liquid surface side toward the liquid surface of the liquid to be measured in the reaction vessel. [Claim 5] A chemical analysis apparatus described in any one of claims 1 to 3, characterized in that the sound wave generating mechanism is arranged opposite the side or bottom surface of the reaction vessel and is equipped with a driving mechanism that irradiates sound waves so that the liquid surface of the liquid to be measured is inclined. 6. The chemical analysis apparatus according to claim 4, wherein said sound wave generating mechanism includes an irradiation position adjusting mechanism for changing the irradiation position of the sound wave with respect to said reaction vessel. [Claim 7] A chemical analysis apparatus described in any one of claims 1 to 3, characterized in that the sound wave generating mechanism is configured by arranging multiple sound source units, each of which independently generates sound waves, in an array. [Claim 8] A chemical analysis apparatus as described in claim 7, characterized in that the sound source portion of the sound wave generating mechanism has a divided electrode on one side of a single piezoelectric element, and a single electrode on the other side formed over the entire surface. [Claim 9] A chemical analysis apparatus described in any one of claims 1 to 3, characterized in that the sound wave generating mechanism is equipped with an irradiation position adjustment mechanism that changes the position at which sound is irradiated onto the reaction vessel, and an acoustic wave transmission means between the sound source unit and the reaction vessel.