JP2011033551A - Method for controlling automatic analyzing device and dispensing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic analyzing device capable of solving the problem that accurate dispensing of a minute amount of a sample requires to secure an appropriate and accurate clearance between a sample probe and a reaction vessel at dispensing time, but a height of a bottom surface of each reaction vessel must be measured to control a sample probe lowering amount in dispensing a minute amount because the height of the bottom surface of the reaction vessel varies due to various factors, and accurately measuring the height of the bottom surface of the reaction vessel at low cost and with a simple mechanism, and maintaining a microscale dispensing accuracy. <P>SOLUTION: The device uses a liquid level detecting function to detect the height of the reaction vessel, and controls a position of the sample probe, while operating the sample probe. By installing a grounded conductive member on the sidewall of the reaction vessel, the height of the bottom surface of the reaction vessel is measured and corrected for each reaction vessel without setting a threshold value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an automatic analyzer that automatically analyzes components in a biological sample such as blood and urine, and in particular, an automatic analysis in which a part is collected from a container containing a sample or reagent and dispensed into a reaction container. Relates to the device.

  In recent years, in automatic analyzers, the amount of reaction solution has been reduced in consideration of burdens on patients and reduction of running costs. In order to perform an accurate analysis using a trace amount sample or a trace reagent, a technique for accurately dispensing a trace amount of liquid into a reaction container is required.

  When dispensing a small amount of sample or reagent, do not dispense empty liquids where the liquid is poorly dispensed, or liquids that should have been dispensed to the outer wall of the probe during dispensing will be brought back out of the reaction vessel. Must not be.

  Conventionally, as disclosed in Patent Document 1, by dispensing a probe that has sucked a liquid to be dispensed in a state pressed against the bottom surface of a reaction container to be dispensed, the trace liquid is dispensed to the bottom surface of the reaction container. It was. In this case, by using a probe whose tip is cut obliquely, even if the probe is pressed against the bottom surface of the reaction vessel, a small amount of liquid can be spotted on the bottom surface of the reaction vessel without blocking the probe opening and can be dispensed. Become.

  Patent Documents 2 and 3 also disclose a method of dispensing a trace amount of liquid with a minute distance between the probe and the bottom surface of the reaction vessel.

JP 2002-156382 A JP 2002-344426 A JP-A-6-242126

  The technique disclosed in Patent Document 1 has the following drawbacks.

  In other words, the tip of the sample probe cut obliquely contacts the bottom surface of the reaction container every time the sample is dispensed, so that the tip of the sample probe or the bottom surface of the reaction container is damaged and the dispensing accuracy is lowered. It is. In particular, when dispensing with an accuracy of 1 μl or less, the tip of the sample probe is thin and sharp, and the tip of the sample probe is easily damaged. Since the sample dispensing accuracy depends on the tip shape of the sample probe, in order to perform stable and accurate dispensing, a method of dispensing a minute amount without damaging the sample probe tip or the bottom of the reaction container is desired. ing.

  If the methods described in Patent Documents 2 and 3 are used, it is possible to prevent the tip of the probe from coming into contact with the bottom surface of the reaction vessel and deteriorating. However, it is known that the height of the bottom surface of the reaction container in the automatic analyzer is not always constant, and there is a slight variation for each reaction container. This is because the reaction vessel is installed on the circumference of a disk and is divided into several blocks and fixed with screws, so that the height of the bottom of the reaction vessel varies if the screwing strength differs in each block. It is because it ends up. Similarly, when the horizontality of the reaction disk on which the reaction vessel is placed is distorted, it is considered that the reaction vessel bottom surface height also varies. In addition, since it is manufactured from a resin molded product, a slight warp due to heat shrink deformation during molding also causes a variation in the bottom height of the reaction vessel.

  In order to dispense a minute amount, it is necessary to control the distance between the bottom surface of the reaction vessel and the probe tip to about 0.1 mm. It is necessary to correct the descending distance of the probe in consideration of the injection.

  In view of the above-described problems, an object of the present invention is to provide an automatic analyzer that can accurately control the gap between the probe tip and the reaction vessel bottom surface in order to accurately dispense a minute amount.

  The configuration of the present invention for achieving the above object is as follows.

  An automatic analyzer comprising: a probe that sucks and discharges liquid; a reaction container that contains the liquid discharged from the probe; and a capacitance measuring mechanism that measures a capacitance between the probe and the reaction container An automatic analyzer comprising a first conductive member at a position between the bottom surface of the reaction vessel and the opening and at a known distance from the bottom surface of the reaction vessel.

  Here, the probe is a thin cylindrical member that sucks a sample such as a sample or a reagent, and communicates with a mechanism such as a syringe for controlling the pressure to suck and discharge a desired amount of liquid.

  In addition, the predetermined thickness of the conductive material is determined depending on the accuracy with which the distance between the probe tip and the reaction vessel bottom is controlled.

  In addition to the first conductive member, the probe may be provided with a second conductive member. In this case, the first and second conductive members have a distance from the bottom surface of the reaction container in which the first conductive member is installed is larger than a distance from the probe tip in which the second conductive member is installed. Is also getting bigger.

  As another configuration of the present invention, a dispensing mechanism including a probe for sucking and discharging a liquid, a reaction container having a bottom surface, a side wall, and an opening and containing a liquid discharged by the probe, and the reaction container is a bottom surface A conductive member having a predetermined thickness at a position where the height between the opening and the opening is known, and the probe has a known height from the probe tip, and the conductive member provided in the reaction vessel A conductive member having a predetermined thickness at a position where the distance from the probe tip is smaller than the distance between the bottom surface and the bottom surface, and between the conductive member provided in the reaction vessel and the conductive member provided in the probe An automatic analyzer having a capacitance measuring mechanism for measuring the capacitance of the probe; and a step of lowering the probe in the reaction vessel; and a conductive member provided in the reaction vessel generated during the descent. Said Measuring a capacitance between the conductive member provided in the lobe, calculating a descending amount of the dispensing mechanism when the measured capacitance becomes maximum, and descending the probe A method for controlling the dispensing mechanism, comprising: calculating a height of the bottom surface of the reaction vessel from a quantity; and storing the calculated height of the bottom surface of the reaction vessel for each of a plurality of reaction vessels. .

  Here, when calculating the height of the bottom surface of the reaction vessel from the probe lowering amount, since the reaction vessel is molded, it is assumed that the height of the vessel is uniform among a plurality of reaction vessels. The position obtained by subtracting the height of the conductive member provided in the reaction vessel from the position where the electric capacity is maximum is calculated as the bottom surface position of the reaction vessel.

  As another configuration for achieving the object of the present invention, a configuration in which another monitoring mechanism is installed in place of the capacitance measuring mechanism and the passage of the probe when the probe is lowered is also conceivable. In this case, the probe does not require a special detection mechanism, and the same effect as the above invention can be obtained.

  According to the present invention, with the above-described configuration, the electrostatic capacity detection mechanism used for the liquid level detection function provided in the conventional automatic analyzer is diverted so that the bottom height of the reaction vessel formed in a series is increased. You can easily know the variation.

  In addition, as another effect of the present invention, the bottom surface height can be calculated for each reaction container, so that even if there is a variation in height for each reaction container, it can be accurately corrected and accurately dispensed in a minute amount. Is possible.

  In addition, since the positional relationship between the probe and the reaction vessel is detected using the maximum capacitance, for example, even when the lowering position of the probe deviates from the center with respect to the reaction vessel, it is highly accurate. The positional relationship between the reaction vessel and the probe can be detected.

Schematic diagram of a general automatic analyzer. A reaction vessel in the form of a divided block. Height measurement method using liquid level detection. Capacitance change during sample probe descent. Positional relationship between sample probe and reaction vessel. Capacitance change during lowering of the sample probe when no conductive plate is arranged. Sample probe using shield tube. Sample probe that uses a shield tube and does not have protrusions. The shape of the conductive plate. Example of attaching conductive plate to reaction vessel block. The example which used the holder of the reaction container as the electrically conductive plate. An embodiment using a CCD camera.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an outline of a general automatic analyzer in which the present invention is implemented.

  Since the function of each part is well-known, detailed description is omitted.

  The sampling arm 2 of the sampling mechanism 1 moves up and down and rotates. Using the sample probe 3 attached to the sampling arm 2, the sample in the sample container 101 arranged on the sample disk 102 rotating left and right is sucked and reacted. It is configured to dispense into the container 5. As can be seen from this figure, the sample container 101 is placed on the sample disk 102 in a universal arrangement in which the sample container 101 can be placed directly on the sample disk 102 or on the test tube (not shown). In general, a structure that can cope with the above is applicable.

  On the rotatable reagent disk 125, reagent bottles 112 corresponding to a plurality of analysis items to be analyzed are arranged. The reagent dispensing probe 110 attached to the movable arm dispenses a predetermined amount of reagent from the reagent bottle 112 to the reaction container 5.

  The sample probe 3 performs a sample suction operation and a dispensing operation in accordance with the operation of the sample pump 107. The reagent dispensing probe 110 performs a reagent aspirating operation and a dispensing operation with the operation of the reagent pump 111. Analysis items to be analyzed for each sample are input from an input device such as the keyboard 121 or the screen of the CRT 118. The operation of each unit in this automatic analyzer is controlled by the computer 103.

  As the sample disk 102 rotates intermittently, the sample container 101 is transferred to the sample suction position, and the sample probe 3 is lowered into the stopped sample container. When the tip of the sample probe 3 comes into contact with the liquid level of the sample in accordance with the lowering operation, a detection signal is output from the liquid level detection circuit 151, and based on this, the computer 103 stops the lowering operation of the driving unit of the sampling arm 2. Control. Next, after a predetermined amount of sample is sucked into the sample probe 3, the sample probe 3 rises to the top dead center. While the sample probe 3 is sucking the sample by a predetermined amount, the pressure detection circuit 153 uses the signal from the pressure sensor 152 to detect the pressure fluctuation in the channel during the suction operation between the sample probe 3 and the sample pump 107 channel. If an abnormality is detected in the pressure fluctuation during the suction, there is a high possibility that the predetermined amount is not sucked, so an alarm is added to the analysis data.

  Next, the sampling arm 2 rotates in the horizontal direction, the sample probe 3 is lowered at the position of the reaction vessel 5 on the reaction disk 4, and the sample held in the reaction vessel 5 is dispensed. When the reaction container 5 containing the sample is moved to the reagent addition position, a reagent corresponding to the corresponding analysis item is added from the reagent dispensing probe 110. As the sample and reagent are dispensed, the liquid level of the sample in the sample container 101 and the reagent in the reagent bottle 112 is detected. The mixture in the reaction vessel to which the sample and the reagent are added is stirred by the stirring mechanism 113. The reaction container containing the mixture is transferred to the photometer 115, and the luminescence value or absorbance of each mixture is measured by a photomultiplier tube as a measuring means or the photometer 115. The light emission signal or light reception signal enters the computer 103 via the interface 104 via the A / D converter 116, and the concentration of the analysis item is calculated. The analysis result is printed out to the printer 117 via the interface 104 or output to the CRT 118 and stored in the memory 122. After completion of photometry, the reaction vessel 5 is washed at the position of the reaction vessel washing mechanism 119. The cleaning pump 120 supplies cleaning water to the reaction container and discharges waste liquid from the reaction container. In the example of FIG. 1, three rows of container holders are formed so that three rows of sample vessels 101 can be set concentrically on the sample disc 102, and one sample suction position by the sample probe 3 is provided in each row. It is set one by one.

  The above is the general operation of the automatic analyzer. For minute dispensing of 1 μL or less, it is effective to control the gap between the sample probe and the bottom surface of the reaction vessel with an accuracy of about 0.1 mm. However, in the actual apparatus, the height of each reaction vessel bottom surface 201 varies with respect to the sample probe 3. As a cause of this variation, since the reaction vessel 5 is made of a resin molded product, a slight warp occurs due to heat shrinkage deformation at the time of molding, or a split block shape is formed as shown in FIG. In order to use the plurality of reaction vessel blocks 17 fixed to the reaction disk 4 with screws, the reaction vessel 5 may be deformed. Some reaction disks 4 have a diameter of several tens of centimeters to more than 1 m, and the level of the reaction disk 4 is an error factor.

  A general electrostatic capacitance type liquid level detection circuit 151 mounted on the automatic analyzer is based on a change in electrostatic capacitance between electrodes disposed at a position facing the sample probe 3, and the tip of the sample probe 3. It is a circuit for detecting contact with the sample liquid surface. The electrode facing the sample probe 3 is connected to the GND potential using the conductive resin of the sample disk 102 on which the sample container is installed.

  In the present invention, the liquid level detection circuit 151 of the sample probe 3 is used to accurately detect the distance between the sample probe 3 and each reaction vessel bottom surface 201 and to control the position of the sample probe 3.

  Next, an example of an embodiment of the present invention is shown.

  Hereinafter, the outline of the operation will be described with reference to FIG.

  FIG. 3a shows a state in which the sample probe 3 is swung onto the reaction vessel at the maximum height position.

  The sample probe 3 is provided with a protrusion 211. The protrusion 211 is made of a conductive material and is electrically connected to the sample probe 3 that also serves as an electrode for detecting the liquid level. A conductive plate 212 is disposed at the upper end of the side wall of the reaction vessel 5 and is connected to the GND potential. FIG. 4 is a capacitance change signal during the lowering operation of the sample probe 3. The axis indicates the descending distance of the sample probe 3, the vertical axis indicates the capacitance value, and points a, b, and c in FIG. 4 correspond to FIGS. 3a, 3b, and 3c, respectively.

  When the sample probe 3 starts to descend, the capacitance between the sample probe 3 and the conductive plate 212 gradually increases, and the capacitance value takes a peak 215 at the point b. If the descent continues further, the capacitance decreases. Note that the point D1 is the passage timing of the lower end of the protrusion 211 on the conductive plate 212, and the point D2 is the passage timing of the upper end of the protrusion 211.

  By disposing the protrusion 211 and the conductive plate 212 in this way, a point where the center position of the thickness 213 of the protrusion 211 passes the center position of the thickness of the conductive plate 212 can be detected. The distance L1 between the tip of the sample probe 3 and the center of the protrusion 211 and the distance L2 between the bottom surface 201 of the reaction vessel and the center of the conductive plate 212 shown in FIG. 3b are measured and stored in advance. A distance Lx from the peak 215 detection position to the reaction vessel bottom surface 201 is obtained by L2-L1. Here, when the gap between the bottom surface 201 of the reaction vessel and the tip of the sample probe 3 is positioned at Lg, the necessary moving distance is Lx−Lg.

  Here, since each reaction vessel 5 is manufactured using a mold for resin, it is not difficult to manage the dimensional accuracy of the reaction vessel 5 and the dimensional accuracy of the mounting surface and the bottom surface of the conductive plate 212.

  Further, the accuracy of the thickness 214 of the conductive plate 212 attached to each reaction vessel is detected as the peak value of the capacitance at the center position of the thickness, so the thickness error is halved as the position detection error. When the position detection accuracy is 0.1 mm or less, the thickness error of all the conductive plates 212 may be 0.2 mm or less, but this can be easily realized. In the present invention, in order to know the positional relationship by detecting the peak of the capacitance change, a positional error in the XY direction between the position of the sample probe 3 and the center position of the reaction vessel 5 as shown in FIG. Even when 205 is present, accurate position detection is possible without any influence. On the other hand, FIG. 6 shows a case where height correction of the bottom surface of the reaction container is performed by diverting the conventional liquid level detection circuit 151 in which the conductive plate 212 is installed on the bottom surface of the reaction container.

  Compared with FIG. 4 showing the capacitance change when this method is used and FIG. 6 showing the capacitance change when the conductive plate 212 is installed on the bottom surface of the reaction vessel as in the conventional method, FIG. Although the capacitance increases gradually as the sample probe 3 descends, the positional relationship between the sample probe 3 and the reaction vessel cannot be detected.

  Further, as shown in FIG. 5, the detected increase curve of the capacitance also changes due to the position error 205 in the XY direction between the lowered position of the sample probe 3 and the reaction cell center position. Even if it is set, it is difficult to accurately detect the positional relationship between the reaction container and the sample probe 3.

  It is extremely difficult to accurately maintain the position of the sample probe 3 in the XY direction with respect to all of the 100 reaction vessels or more in one rotation, and the realization requires a great deal of cost, so the feasibility is extremely high. Low. Further, even in the configuration in which the protruding portion 211 is removed from FIG. 3, the peak 215 in FIG. 4 is not detected, so that accurate position detection cannot be performed due to the influence of the position error 205 in the XY direction.

  The protrusion 211 may be the material of the sample probe 3 or other conductive material. Although it is desirable that the protrusion thickness 213 is thin, since the position can be adjusted with high accuracy, it is desirable. About 0mm would be appropriate.

  Moreover, although the protrusion 211 and its substituteable embodiment are represented by a cylindrical shape, the essence of the present invention is that a capacitance peak can be obtained during the descending operation, so that the cross-sectional shape is a square. But it may be a star shape. Further, the sample probe 3 may be tapered in the vertical direction. The timing for correcting the variation in the bottom height of the reaction vessel 5 may be performed at the time of exchanging the sample probe 3, at the time of exchanging the reaction vessel 5, at the time of device initialization operation, at the time of device maintenance, or any of them. The variation in the bottom height of the reaction vessel 5 occurs mainly when the reaction vessel 5 is replaced. If the value corrected at that timing is stored, the bottom height of the reaction vessel 5 changes during normal operation. This is because it is not considered.

  Next, another embodiment of the present invention is shown as Example 2.

  FIG. 7 and FIG. 8 are configuration examples of the sample probe 3 that has the same effect without mounting the projection 211 using the shield tube 216. The sample probe 3 is made of a conductive material, and the shield tube 216 attached to the sample probe 3 is connected to the GND potential in the same manner as the conductive plate 212 provided in the reaction vessel. In other words, the capacitance covered by the portion covered by the shield tube 216 does not change even when approaching the conductive plate 212, so that the electrode thick portion 217 has the same function as the protrusion 211 of the sample probe 3 in FIG. To do. Since the length of the electrode thick portion 217 is limited by the shield tube 216, a change in capacitance having a peak similar to that in FIG. 4 is measured.

  FIG. 8 shows an example in which a peak is obtained by attaching a shield tube 216 to the conductive sample probe 3 and limiting the length of the electrode portion 218 as another method for realizing the present embodiment.

  Another embodiment of the present invention is shown as Example 3.

  FIG. 9 shows an example of the conductive plate 212. FIG. 9 a shows an example in which the conductive plate opening 220 is made larger than the reaction container 5 opening. FIG. 9 b shows an example in which the conductive plate opening 220 is made smaller than the reaction container 5 opening. FIG. 9c shows an example in which the shape of the opening is rectangular. In FIG. 9, one conductive plate 212 is shown in one reaction vessel 5, but by using one conductive plate 212 by punching one plate in a unit of reaction vessel block 17, etc. Cost can be reduced. Further, by selecting the material and thickness of the conductive plate 212 that can provide rigidity and increasing the number of fixing points, the effect of preventing warpage of the reaction vessel block 17 can be obtained.

  Further, as shown in FIG. 10, this is an example in which one conductive plate 212 is attached to the reaction vessel block 17 in the simplest shape. It has been confirmed that there is no problem even if the conductive plate 212 has a thickness of several tens of μm, and the conductive plate 212 can be realized by applying a conductive paint or applying conductive plating. Further, the installation position of the conductive plate 212 is not limited to the upper surface of the reaction vessel 5, and the protrusion can pass through the conductive plate 212 until the sample probe 3 descends and reaches the bottom surface of the reaction vessel 5. I just need it. Therefore, if position accuracy is obtained, the conductive plate 212 may exist inside the resin of the reaction vessel 5 and be integrally formed.

  FIG. 11 shows a reaction vessel block 17 in which a plurality of reaction vessels 5 are fixed to a holder 221. The reaction vessel 5 alone, which requires optical characteristics, and the holder 221 that is the purpose of fixing need not be made of the same material. FIG. 11 a shows an example in which the reaction vessel 5 is inserted from above the holder 221. FIG. 11 b shows an example in which the reaction vessel 5 is inserted from the lower part of the holder 221, which is effective when making the holder 221 smaller than the opening of the reaction vessel 5. Therefore, the holder 221 performs the same function as the conductive plate 212 by molding the holder 221 with a conductive resin material or a resin material mixed with conductive powder.

  The present invention can also be applied to reagent dispensing and pretreatment. In other words, when the present invention is adopted when it is necessary to first dispense a trace amount of liquid into a container, it is a feature that a minute amount of droplets can be reliably dispensed into the container.

  In the maintenance of the apparatus, the sample probe 3 and the reaction container block 17 may be removed and cleaned. However, in the apparatus after the maintenance, a positional deviation occurs between the sample probe 3 and the reaction container 5. On the other hand, if the capacitance peak values between all the reaction vessels 5 and the sample probes 3 are stored before maintenance, and compared with the capacitance peak values after maintenance, the sample probes 3 before and after maintenance are stored. The occurrence of misalignment in the XY direction can be detected. When a misalignment is detected, a warning is displayed on the screen and the operator is urged to calibrate the position of the apparatus, thereby contributing to the reliability of the analysis data so that the analysis data does not change significantly even before and after maintenance.

  Another embodiment of the present invention is shown as Example 4.

  FIG. 12 shows another embodiment of the present invention. In this embodiment, an observation mechanism for the reaction vessel 5 using the CCD camera 202 is provided outside the reaction vessel 5.

  The CCD camera takes an image near the bottom of the reaction vessel 5. As the sample probe 3 descends, the state in which the height between the tip of the sample probe 3 and the bottom surface of the reaction vessel 5 narrows is successively observed, and the sample probe 3 descending is stopped when the preset positional relationship is reached. A small amount of dispensing can be realized without being affected by variations in the height of the bottom surface of each reaction vessel 5 and without damaging the tip of the sample probe 3 or the bottom surface of the reaction vessel 5.

DESCRIPTION OF SYMBOLS 1 Sampling mechanism 2 Sampling arm 3 Sample probe 4 Reaction disk 5 Reaction container 11 Screw hole 17 Reaction container block 101 Sample container 102 Sample disk 103 Computer 104 Interface 107 Sample pump 110 Reagent dispensing probe 111 Reagent pump 112 Reagent bottle 113 Agitation Mechanism 114 Light source lamp 115 Photometer 116 A / D converter 117 Printer 118 CRT
119 Reaction vessel cleaning mechanism 120 Cleaning pump 121 Keyboard 122 Memory 125 Reagent disk 151 Liquid level detection circuit 152 Pressure sensor 153 Pressure detection circuit 201 Reaction vessel bottom surface 205 Range of position error between probe and all reaction vessels 211 Projection 212 Conductive plate 213 Projection thickness 214 Conductive plate thickness 215 Capacitance value peak 216 Shield tube 217 Electrode thickening portion 218 Electrode range 220 Conductive plate opening 221 Holder 222 CCD camera 223 Reaction tank

Claims (14)

A probe for sucking and discharging liquid;
A reaction container containing the liquid discharged by the probe;
A capacitance measuring mechanism for measuring a capacitance between the probe and the reaction vessel;
In an automatic analyzer equipped with
An automatic analyzer comprising a first conductive member at a position between the bottom surface of the reaction vessel and the opening and at a known distance from the bottom surface of the reaction vessel. The automatic analyzer according to claim 1, wherein
An automatic analyzer comprising a second conductive member having a predetermined thickness in the axial direction of the probe at a position provided in the probe and having a known distance from the tip of the probe. The automatic analyzer according to claim 2,
The distance from the reaction vessel bottom surface of the first conductive member,
An automatic analyzer characterized by being larger than the distance from the probe tip of the second conductive member. The automatic analyzer according to claim 3,
An automatic analyzer comprising a distance calculation mechanism for calculating a relative distance between the probe and the reaction container based on a capacitance measurement value measured by the capacitance measurement mechanism. The automatic analyzer according to claim 1, wherein
The automatic analyzer according to claim 1, wherein the first conductive member is provided at an upper end of a side wall of the reaction vessel. The automatic analyzer according to claim 1, wherein
The automatic analyzer according to claim 1, wherein the first conductive member is provided so as to surround a side wall of the reaction vessel. The automatic analyzer according to claim 1, wherein
The automatic analyzer according to claim 1, wherein the first conductive member is provided in a side wall of the reaction vessel. The automatic analyzer according to claim 1, wherein
The automatic analyzer is characterized in that the first conductive member is a holder for fixing and holding the reaction vessel. The automatic analyzer according to claim 1, wherein
An automatic analyzer having a conductive portion obtained by plating a conductive member on a part of the reaction vessel as the first conductive member. The automatic analyzer according to claim 2,
The probe made of a conductive member;
A cylindrical shield covering a part of the probe,
The automatic analyzer is characterized in that the second conductive member is the probe not covered with the shield. The automatic analyzer according to claim 2,
An automatic analyzer comprising a protrusion made of a conductive member as a part of the probe as the second conductive member. The automatic analyzer according to claim 1, wherein
The automatic analyzer according to claim 1, wherein the predetermined thickness error of the first conductive member is 0.2 mm or less. The automatic analyzer according to claim 2,
The automatic analyzer according to claim 1, wherein the predetermined thickness of the second conductive member is 0.1 mm to 4 mm. A dispensing mechanism having a probe for sucking and discharging liquid;
A reaction vessel having a bottom surface, a side wall, and an opening and containing a liquid discharged from the probe;
The reaction vessel has a predetermined thickness at a position where the height between the bottom and the opening is known; and
The probe has a known height from the probe tip, and a conductive member having a predetermined thickness at a position where the distance from the probe tip is smaller than the distance between the conductive member provided on the reaction vessel and the bottom surface. With
In an automatic analyzer comprising a capacitance measuring mechanism for measuring a capacitance between a conductive member provided in the reaction vessel and a conductive member provided in the probe,
Lowering the probe into the reaction vessel;
Measuring the capacitance between the conductive member provided in the reaction vessel and the conductive member provided in the probe, which occurs during the descent;
Calculating a descending amount of the dispensing mechanism when the measured capacitance becomes maximum;
Calculating the height of the bottom surface of the reaction vessel from the descending amount of the probe;
Storing the calculated height of the bottom of the reaction vessel for each of a plurality of reaction vessels;
A method for controlling a dispensing mechanism, comprising:

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