Automatic analysis device and analysis method

Abstract

The present invention comprises: a mechanism unit that uses a solvent delivered from a container that accommodates the solvent; a weight sensor that detects the weight of the container in a state in which the solvent is accommodated, and outputs a detection signal corresponding to the detected weight; a calculation unit that, on the basis of the detection signal from the weight sensor, executes a liquid amount calculation for calculating the amount of the solvent accommodated in the container; and a control unit that controls the calculation unit and the mechanism unit, the control unit executing liquid amount calculation on the basis of the detection signal from the weight sensor when the amount of change per predetermined time of the detection signal is within a predetermined threshold value range between the increase side and the decrease side of the detection signal when the solvent is used by the mechanism unit, and the control unit controlling the calculation unit so as to exclude the detection signal as a subject of the liquid amount calculation when the amount of change per predetermined time of the detection signal from the weight sensor is outside the threshold value range. Thus, by suppressing the influence of disturbing factors, remaining amount management can be performed more accurately.

Description

Automated analyzer and analysis method

[0001] The present invention relates to an automatic analyzer and an analysis method.

[0002] Automated analyzers automatically perform the entire process from measuring the components to outputting the results by reacting blood, urine, or other biological samples (hereinafter referred to as "samples") with analytical reagents that specifically react with the components to be measured in the sample, and quantitatively detecting the complexes formed by this reaction using spectroscopic techniques such as electrochemiluminescence.Such automated analyzers are one of the devices required for efficient analysis at testing centers and other medical research facilities that undertake testing of samples requested by hospitals and clinics.

[0003] Here, Patent Document 1 discloses a liquid chromatograph in which a filter that smooths and outputs the output signal of a sensor that detects the weight of a container containing a mobile phase is configured so that when the amount of change in the sensor output signal per unit time is greater than a predetermined threshold, the smoothing time constant of the filter is smaller than when the amount of change is smaller than the threshold.

[0004] Japanese Patent Application Laid-Open No. 2021-043099

[0005] In a configuration using a weight sensor to manage the remaining amount of reagents, etc., as in the above-mentioned conventional technology, there is a concern that the readings of the weight sensor may fluctuate due to external disturbances such as vibrations, making it impossible to properly manage the remaining amount of reagents, etc.

[0006] The present invention has been made in view of the above, and has as its object to provide an automatic analyzer and an analysis method that can more accurately manage remaining amounts by suppressing the influence of disturbance factors.

[0007] The present application includes multiple means for solving the above problem, and one example thereof includes a mechanism that uses solvent delivered from a container that contains the solvent; a weight sensor that detects the weight of the container containing the solvent and outputs a detection signal corresponding to the detected weight; a calculation unit that performs a liquid volume calculation to calculate the liquid volume of the solvent contained in the container based on the detection signal of the weight sensor; and a control unit that controls the calculation unit and the mechanism, wherein when the solvent is used by the mechanism, if the amount of change per predetermined time in the detection signal of the weight sensor is within a predetermined threshold range on the increasing and decreasing sides of the detection signal, the control unit controls the calculation unit to perform a liquid volume calculation based on the detection signal, and if the amount of change per predetermined time in the detection signal of the weight sensor is outside the threshold range, the control unit controls the calculation unit so as to exclude the detection signal from the liquid volume calculation.

[0008] According to the present invention, the influence of disturbance factors is suppressed, thereby making it possible to more accurately manage the remaining amount.

[0009] 1 is a diagram showing a schematic view of the overall configuration of an automatic analyzer; 2 is a diagram showing a system reagent supply mechanism together with related configurations; 3 is a flowchart showing the contents of a liquid volume calculation process; 4 is a diagram showing an example of liquid volume calculation; 5 is a diagram showing the amount of weight change based on the detection signal of a weight sensor when vibration is affecting as an external disturbance factor; 6 is a diagram showing an example of the relationship between the transition of the detection signal of a weight sensor and a threshold value; 7 is a diagram showing an example of the relationship between the transition of the detection signal of a weight sensor and a threshold value; 8 is a diagram showing the relationship between the operating conditions of a mechanism unit and the amount of liquid used, etc.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that, although the present embodiment will be described using an automatic analyzer as an example, the present invention is not limited to this and can also be applied to other devices such as a liquid chromatograph.

[0011] First Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIG.

[0012] FIG. 1 is a diagram showing a schematic overall configuration of an automatic analyzer.

[0013] In Figure 1, the automatic analyzer 100 is roughly composed of an analysis unit 101 equipped with a sample disk 102, a sample dispensing mechanism 104, a reagent storage cabinet 105, a reagent disk 106, a reagent dispensing mechanism 108, a magnetic particle stirring arm 112, a reaction vessel disposal hole 113, an incubator block 114, a reaction liquid stirring mechanism 115, a reaction vessel tray 116, a first reaction vessel transport mechanism 117, a second reaction vessel transport mechanism 119, an immunodetection mechanism 120, etc., and a control unit 200.

[0014] The control unit 200 controls the overall operation of the automatic analyzer 100, and is composed of, for example, a hardware board and a computer, and is connected to a storage device such as a hard disk.

[0015] A plurality of sample containers 103 are arranged in a ring shape on the sample disk 102. When dispensing a sample, the disk rotates clockwise and counterclockwise to transport the sample containers 103 to an access position of the sample dispensing mechanism 104.

[0016] For the purpose of simplifying sample management, for example, an identification barcode is attached to the sample container 103. Information regarding the sample ID and sample type is written in the barcode. The barcode attached to the sample container 103 is read by a barcode reader.

[0017] The sample dispensing mechanism 104 is composed of a rotation drive mechanism, a vertical drive mechanism, and a dispensing nozzle. The dispensing nozzle of the sample dispensing mechanism 104 is moved between a sample aspirating position and a sample discharging position 118 by the rotation drive mechanism and the vertical drive mechanism.

[0018] The reagent storage 105 includes a reagent disk 106 having a plurality of reagent container holders 107 arranged in a ring. The reagent storage 105 has, for example, a cooling function to enhance the on-board stability of reagent properties. Each of the plurality of reagent container holders 107 on the reagent disk 106 holds a reagent container containing a reagent to be used for analysis. The reagent disk 106 has a rotation drive mechanism, and by rotation, moves each reagent container to a predetermined position on the circumference.

[0019] The reagent dispensing mechanism 108 is composed of a rotation drive mechanism, a vertical drive mechanism, and a dispensing nozzle. The dispensing nozzle of the reagent dispensing mechanism 108 rotates and descends to the position of a predetermined type of reagent container on the reagent disk 106, aspirates a predetermined amount of reagent, then ascends, and then rotates and descends to a reagent dispensing position 111, where it dispenses the reagent into a reaction container placed at the reagent dispensing position 111.

[0020] A magnetic particle stirring arm 112 (also called a stirrer) having a magnetic particle stirring element as stirring means is set on the reagent disk 106. The magnetic particle stirring arm 112 moves to an upper region of a reagent container containing the magnetic particle solution to be stirred, lowers the magnetic particle stirring element, and stirs the magnetic particle solution by rotating the magnetic particle stirring element. To prevent spontaneous precipitation of the magnetic particles in the magnetic particle solution, the magnetic particle stirring arm 112 stirs the magnetic particle solution immediately before the reagent is dispensed.

[0021] In the immunoanalysis process by the automatic analyzer 100, the processes are performed in the following order: sample dispensing process, reagent dispensing process, reaction process, and detection process.

[0022] The first reaction vessel transport mechanism 117 has drive mechanisms in the X-axis, Y-axis, and Z-axis directions, and moves above the reaction vessel disposal hole 113, the incubator block 114, the reaction liquid stirring mechanism 115, and the reaction vessel tray .

[0023] In the sample dispensing process, the first reaction container transport mechanism 117 moves the reaction container from the reaction container tray 116 to the sample dispensing position 118. The sample dispensing mechanism 104 dispenses a predetermined amount of sample into the reaction container placed at the sample dispensing position 118. The reaction container from which the sample has been dispensed is then moved to the reagent dispensing position 111 by the second reaction container transport mechanism 119. The second reaction container transport mechanism 119 has a rotation drive mechanism, a vertical drive mechanism, and a reaction container gripping mechanism, and has the function of moving the reaction container to each reaction container placement position (reagent dispensing position 111, incubator block 114, reaction liquid stirring mechanism 115, sample dispensing position 118, reaction liquid aspirating position 121, etc.) placed on the rotational orbit.

[0024] In the reagent dispensing process, the reagent dispensing mechanism 108 dispenses a predetermined amount of reagent into a reaction vessel placed at the reagent dispensing position 111. The reaction vessel is then moved to the reaction liquid stirring mechanism 115 by the second reaction vessel transport mechanism 119. After the reaction liquid has been stirred, the reaction vessel is moved to the incubator block 114 by the first reaction vessel transport mechanism 117.

[0025] In the reaction process, the reaction process is carried out in an incubator block 114, the temperature of which is controlled to an appropriate temperature in order to promote the reaction between the sample and the reagent. When the reaction process between the sample and the reagent in the incubator block 114 is completed, the reaction vessel is moved to a sample discharge position 118 by a first reaction vessel transport mechanism 117. Thereafter, the reaction vessel is moved to a reaction liquid suction position 121 provided below the immunodetection mechanism 120 by a second reaction vessel transport mechanism 119.

[0026] In the detection process, the reaction liquid is sucked into the detection unit in the immunodetection mechanism 120, and measurement is performed. After measurement, the reaction vessel is moved to the sample discharge position 118 by the second reaction vessel transport mechanism 119, and then discarded into the reaction vessel disposal hole 113 by the first reaction vessel transport mechanism 117.

[0027] In the automatic analyzer 100 configured as described above, the weight of a container containing a solvent (e.g., a system reagent) used in a certain mechanism is detected by a weight sensor, and the liquid volume of the solvent contained in the container is calculated (liquid volume calculation) based on the detection result (output signal) of the weight sensor, and the remaining volume is managed.

[0028] The following description will use a system reagent as an example of a solvent to be managed for remaining amount, but the present invention can also be applied to other types of solvents as long as the remaining amount is managed using the detection results of a weight sensor.

[0029] FIG. 2 is a diagram illustrating the system reagent supply mechanism and related components in the automatic analyzer.

[0030] As shown in Figure 2, the system reagent supply mechanism has a container 201 that contains a solvent (e.g., a system reagent), and the system reagent is delivered to a mechanism section 204 that uses it via a flow path section 206 formed in a tube that is inserted into the container 201 and supported by a tube lifter 205.

[0031] A photointerrupter 208 that detects the passage of a system reagent is provided in the flow path section 206. When a system reagent (solvent), which is an object to be detected, passes through the flow path section 206, which is arranged between a light-emitting element and a light-receiving element facing each other, the photointerrupter 208 detects the presence or absence of the system reagent by blocking light from the light-emitting element to the light-receiving element.

[0032] The container 201 is placed on a weight sensor 202, and the total weight of the container 201 and the system reagent contained in the container 201 is detected by the weight sensor 202. The weight sensor 202 transmits a detection signal corresponding to the detected weight of the container 201 (and the system reagent) to the calculation unit 203. For example, if the weight detected by the weight sensor 202 increases, the detection signal also increases according to the amount of increase, and if the detected weight decreases, the detection signal also decreases according to the amount of decrease.

[0033] The calculation unit 203 performs a liquid volume calculation (liquid volume calculation process) to calculate the liquid volume of the system reagent contained in the container 201 based on the detection signal from the weight sensor 202 and the control signal from the control unit 200, and outputs the calculation result to the control unit 200. Since the detection signal from the weight sensor 202 indicates the amount of change (increase or decrease) according to the weight of the container 201, the amount of change in the weight of the container 201 (i.e., the liquid volume of the solvent) can be calculated from the amount of change in the detection signal. The calculation unit 203 can also calculate the remaining amount of solvent contained in the container 201 using information such as the base weight of the container 201 and the initial amount of solvent.

[0034] The mechanism unit 204 performs operations including the use of system reagents based on control signals from the control unit 200, and outputs information relating to the operating state to the control unit 200 as necessary.

[0035] The control unit 200 controls the system reagent supply mechanism including the calculation unit 203 and the mechanism unit 204, and the overall operation of the automatic analyzer 100. Below, the liquid volume calculation process in the calculation unit 203 under the control of the control unit 200 will be particularly described.

[0036] For example, when a solvent is used by the mechanism part 204, if the amount of change in the detection signal of the weight sensor 202 per predetermined time (unit time) is within a predetermined threshold range (including above the threshold) on the increasing and decreasing sides of the detection signal, the control part 200 performs a liquid volume calculation based on the detection signal, and if the amount of change in the detection signal of the weight sensor 202 per predetermined time (unit time) is outside the threshold range, the control part 200 controls the calculation part to exclude the detection signal from the liquid volume calculation.

[0037] The output unit 207 outputs analysis results and the like from the automated analyzer 100, and is, for example, a display device such as a monitor. For example, when the control unit 200 determines, based on the result of the liquid volume calculation, that the remaining amount of system reagent (solvent) contained in the container 201 is less than a predetermined value, the control unit 200 notifies the operator by displaying a message on the output unit 207 indicating that the remaining amount of system reagent in the container 201 is low, and prompts the operator to replace the container 201. Furthermore, when the detection signal of the weight sensor 202 is excluded from the liquid volume calculation, i.e., when the change in the detection signal per unit time is outside the threshold range, for example, the control unit 200 considers the possibility of an abnormality in the delivery of the system reagent to the mechanism unit 204 and issues an alarm to the analysis results related to the operation of the mechanism unit 204 at this timing. Furthermore, when the number of times the detection signal of the weight sensor 202 is excluded from the liquid volume calculation exceeds a predetermined number (threshold), the control unit 200 considers the possibility of an abnormality in the system reagent supply mechanism including the weight sensor 202 and displays an alarm indicating this on the output unit 207 to alert the operator.

[0038] FIG. 3 is a flowchart showing the contents of the liquid volume calculation process.

[0039] As shown in FIG. 3, the control unit 200 determines whether or not the system reagent (solvent) has been used based on the control state (or operating state) of the mechanism unit 204 (step S100), and if the determination result is NO, the processing is terminated.

[0040] If the determination result in step S100 is YES, the control unit 200 causes the calculation unit 203 to acquire the detection signal of the weight sensor 202 (step S110), and calculates the amount of change in the detection signal per unit time (step S120).

[0041] Next, it is determined whether the amount of change calculated in step S120 is within a predetermined threshold range on the increasing and decreasing sides of the detection signal (step S130), and if the determination result is YES, the liquid volume is calculated based on the detection signal (step S140), and the processing is terminated.

[0042] If the result of the determination in step S130 is NO, i.e., if the amount of change calculated in step S120 is outside the range of the predetermined thresholds for the increase and decrease of the detection signal, the detection signal is excluded from the liquid volume calculation (step S150), and the process ends. Also, in step S150, alarms are set for each measurement value and each cycle, and alarms related to the exclusion of the detection results from the liquid volume calculation, as necessary.

[0043] 4 is a diagram showing an example of liquid volume calculation, in which the vertical direction indicates the remaining amount of system reagent (reagent volume X) and the horizontal direction indicates the elapsed time (seconds).

[0044] 4, the threshold value (+ value) on the increasing side of the detection signal is determined based on the standard deviation (SD value: for example, 1.0) of the detection signal from the weight sensor 202. The threshold value (- value) on the decreasing side of the detection signal is determined based on the maximum value (-9 = -4.5 x 2 seconds) of the weight of the system reagent (solvent) used by the mechanism unit 204 per unit time (for example, 2 seconds). The threshold value (- value) on the decreasing side of the detection signal may also be set by adding the standard deviation of the detection signal from the weight sensor 202.

[0045] In the liquid volume calculation shown in FIG. 4, the detection signal is judged based on the correction formula (Δ validity judgment condition), and detection signals that fall outside the threshold range due to a large disturbance are considered outliers and are not used in the liquid volume calculation. That is, ΔV2 (+1.5), ΔV5 (+1.25), and ΔV6 (−10.0) in FIG. 4 are judged to be invalid and excluded from the liquid volume calculation. However, ΔV7 to ΔV14 are not shown in FIG. 4. Potential large disturbances include, for example, vibrations caused by replacing adjacent bottles or opening and closing the device cover.

[0046] FIG. 5 is a diagram showing the amount of change in weight (reading value) based on the detection signal of the weight sensor when vibration is an external disturbance factor, with the reading value (g) on ​​the vertical axis and time (seconds) on the horizontal axis.

[0047] Figure 5 shows the case where the liquid volume calculation rules of this embodiment are applied to the detection signal of the weight sensor 202 (after application of the rules: solid line) in comparison with a comparative example where all detection signals of the weight sensor 202 are used (before application of the rules: dashed line).

[0048] As shown in FIG. 5, before the rule is applied (dashed line), the variation in the read values ​​increases due to the influence of vibration, but after the rule is applied (dashed line), the influence of vibration is suppressed and the variation in the read values ​​is also suppressed.

[0049] 6 is a diagram showing an example of the relationship between the transition of the detection signal (output value) of the weight sensor and the threshold value. In Fig. 6, the transition of the detection signal of the weight sensor 202 is shown in the upper part, and the relationship between the amount of change between two points of the detection signal of the weight sensor 202 and the threshold value is shown in the lower part.

[0050] 6, the threshold value (positive side: the side where the amount of liquid increases) has an upper limit equal to the variation (standard deviation) of the output value of the weight sensor 202. The threshold value (negative side: the side where the amount of liquid decreases) is determined by the sum of the variation of the output value of the weight sensor 202 and the amount of liquid used by the mechanism unit 204 (which is constant and is the maximum amount used per unit time). For example, the threshold value (positive side) is set to +0.5 (standard deviation of the readings of the weight sensor), and the threshold value (negative side) is set to -5.0.

[0051] Then, using the threshold value set in this way, when the solvent is used by the mechanism unit, if the change in the detection signal of the weight sensor per specified time is within the threshold range, the liquid volume calculation is performed based on the detection signal, and if it is outside the threshold range, the detection signal is excluded from the liquid volume calculation, thereby suppressing the effects of external disturbance factors.

[0052] As described above, this embodiment includes a mechanical unit that uses the solvent delivered from the container that contains the solvent; a weight sensor that detects the weight of the container containing the solvent and outputs a detection signal corresponding to the detected weight; a calculation unit that performs a liquid volume calculation to calculate the liquid volume of the solvent contained in the container based on the detection signal from the weight sensor; and a control unit that controls the calculation unit and the mechanical unit.When the solvent is used by the mechanical unit, the control unit is configured to perform a liquid volume calculation based on the detection signal of the weight sensor if the amount of change per predetermined time in the detection signal from the weight sensor is within a predetermined threshold range on the increasing and decreasing sides of the detection signal, and to control the calculation unit to exclude the detection signal from the liquid volume calculation if the amount of change per predetermined time in the detection signal from the weight sensor is outside the threshold range.This makes it possible to suppress the effects of external disturbances and to more accurately manage the remaining amount.

[0053] <Modification 1> Modification 1 shows another example of the threshold value used in the liquid volume calculation. Note that in Modification 1, the description of the same configuration as in the first embodiment will be omitted as appropriate. The following description will be given with reference to FIGS. 7 and 8.

[0054] Fig. 7 is a diagram showing an example of the relationship between the transition of the detection signal (output value) of the weight sensor and the threshold value. In Fig. 7, the transition of the detection signal of the weight sensor 202 is shown in the upper part, and the relationship between the amount of change between two points of the detection signal of the weight sensor 202 and the threshold value is shown in the lower part. Fig. 8 is a diagram showing the relationship between the operating conditions of the mechanism unit and the amount of liquid used, etc.

[0055] 7 and 8, the threshold value (positive side: the side where the amount of liquid increases) has an upper limit equal to the variation (standard deviation) of the output value of the weight sensor 202. The threshold value (negative side: the side where the amount of liquid decreases) is determined based on the sum of the standard deviation of the detection signal of the weight sensor 202 and the weight of the system reagent (solvent) used depending on the operating state of the mechanism unit 204. For example, the threshold value (positive side) is set to +0.5 (standard deviation of the reading value of the weight sensor), and the threshold value (negative side) is set to -5.0 (= (calculated amount used) × 1.1 - 0.5 (standard deviation of the reading value of the weight sensor)).

[0056] The other configurations are the same as those of the first embodiment. In the first modification, the same effects as those of the first embodiment can be obtained.

[0057] Furthermore, since the threshold value is determined according to the operating state of the mechanism unit 204, the influence of disturbance factors can be more accurately suppressed, and the remaining amount can be managed more accurately.

[0058] In Modification 2, multiple weight sensors 202 with different containers placed on them are provided, and fluctuations in the read values ​​of the multiple weight sensors 202 are observed. If the respective fluctuations are synchronized, it is determined that there is a disturbance, and the range of the threshold value for the amount of change (Δw) is changed.

[0059] The other configurations are the same as those of the first embodiment. The second modification can also achieve the same effects as those of the first embodiment.

[0060] <Modification 3> Modification 3 shows a case where the measurement cycle is subdivided and the threshold value is specified in detail. That is, in Modification 3, the timing of large (or small) vibrations can be grasped in more detail from the operation cycle of the automated analyzer 100, and the threshold value can be set to correspond to each case.

[0061] The other configurations are the same as those of the first embodiment. The third modification can also achieve the same effects as those of the first embodiment.

[0062] <Modification 4> Modification 4 shows a case where a detection function is provided that determines that an abnormality may have occurred and issues an alarm even when the amount of solvent does not change (does not decrease) during an operation that consumes the solvent (such as liquid transfer). For example, an abnormality can be determined by creating a table of the device status (time chart) and comparing the device status with the detected value of the weight sensor.

[0063] The other configurations are the same as those of the first embodiment. The fourth modification can also achieve the same effects as those of the first embodiment.

[0064] <Modification 5> Modification 5 shows a case where the threshold value and monitoring conditions are changed at a timing when vibration is expected to occur easily. Examples of timing when vibration is expected to occur easily include the time from when the lifter of an adjacent bottle is operated to the time when the bottle exchange is completed (determined by the PI detection status of the lifter), the initialization of the device, the reset operation, and specific timing of operation.

[0065] The other configurations are the same as those of the first embodiment. The fifth modification can also achieve the same effects as those of the first embodiment.

[0066] <Notes> The present invention is not limited to the above-described embodiments, and includes various modifications and combinations within the scope of the gist thereof. Furthermore, the present invention is not limited to those including all of the configurations described in the above-described embodiments, and also includes those in which some of the configurations are omitted. Furthermore, the above-described configurations, functions, etc. may be realized in part or in whole by designing them as, for example, integrated circuits. Furthermore, the above-described configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function.

[0067] 100...automatic analyzer, 101...analysis unit, 102...sample disk, 103...sample container, 104...sample dispensing mechanism, 105...reagent storage, 106...reagent disk, 107...reagent container holder, 108...reagent dispensing mechanism, 111...reagent discharge position, 112...magnetic particle stirring arm, 113...reaction container disposal hole, 114...incubator block, 115...reaction liquid stirring mechanism, 116...reaction container tray, 117...first reaction container transport mechanism, 118...sample discharge position, 119...second reaction container transport mechanism, 120...immunodetection mechanism, 121...reaction liquid suction position, 200...control unit, 201...container, 202...weight sensor, 203...calculation unit, 204...mechanism unit, 205...tube lifter, 206...flow path unit, 207...output unit, 208...photointerrupter

Claims

1. An automatic analyzer comprising: a mechanical unit that uses a solvent delivered from a container that contains the solvent; a weight sensor that detects the weight of the container containing the solvent and outputs a detection signal corresponding to the detected weight; a calculation unit that performs a liquid volume calculation to calculate the liquid volume of the solvent contained in the container based on the detection signal of the weight sensor; and a control unit that controls the calculation unit and the mechanical unit, wherein when the solvent is used by the mechanical unit, the control unit controls the calculation unit to perform a liquid volume calculation based on the detection signal if the amount of change per specified time in the detection signal of the weight sensor is within a predetermined threshold range on the increasing and decreasing sides of the detection signal, and to exclude the detection signal from the liquid volume calculation if the amount of change per specified time in the detection signal of the weight sensor is outside the threshold range.

2. An automatic analyzer according to claim 1, wherein the predetermined threshold value for the increasing side of the detection signal is determined based on the standard deviation of the detection signal of the weight sensor.

3. In the automatic analyzer according to claim 1, the predetermined threshold value for the decreasing side of the detection signal is determined based on the sum of the standard deviation of the detection signal of the weight sensor and the maximum weight of the solvent used per unit time by the mechanism.

4. In the automatic analyzer according to claim 1, the predetermined threshold value for the decreasing side of the detection signal is determined based on the sum of the standard deviation of the detection signal of the weight sensor and the weight of the solvent used according to the operating state of the mechanism part.

5. An automatic analyzer according to claim 1, comprising a plurality of weight sensors on which different containers are placed, and wherein the control unit changes the range of the threshold value when fluctuations in the detection signals of the plurality of weight sensors become synchronized.

6. An automatic analyzer according to claim 1, wherein the control unit issues an alarm if the detection signal of the weight sensor does not change during operation of the mechanism in which the solvent is consumed.

7. The automatic analyzer according to claim 1, wherein the control unit changes the threshold value at a timing when vibration is expected to occur easily.

8. An analytical method comprising the steps of: using a solvent delivered from a container that contains the solvent; detecting the weight of the container containing the solvent and outputting a detection signal corresponding to the detected weight; and performing a liquid volume calculation to calculate the liquid volume of the solvent contained in the container based on the detection signal, wherein, when the solvent is used, if the amount of change in the detection signal per specified time is within a predetermined threshold range on the increasing and decreasing sides of the detection signal, a liquid volume calculation is performed based on the detection signal, and if the amount of change in the detection signal per specified time is outside the threshold range, the detection signal is excluded from the liquid volume calculation.

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