Analysis sample filtering device, and program for analysis sample filtering device

Abstract

An analysis sample filtering device comprising: a filtration container (12) provided with a filter on a lower surface; a recovery container (11) having an intake port and an upper opening to which the filtration container is attached; a depressurization mechanism (44) that depressurizes the internal space of the recovery container via the intake port; a pressure measuring unit (47) that measures the pressure in the internal space of the recovery container; and a depressurization operation control unit (93) that, when a prescribed input operation is performed, starts an operation for depressurizing the internal space of the recovery container by using the depressurization mechanism, and thereafter, when a pressure measurement value measured by the pressure measurement unit or the amount of change in said measurement value over time satisfies a prescribed criterion, stops the operation for depressurizing the internal space of the recovery container performed by the depressurization mechanism.

Description

Filtering Device for Analysis Sample and Program for Filtering Device for Analysis Sample

[0001] The present invention relates to a device for suction filtering a liquid sample to be analyzed.

[0002] A liquid chromatograph is used to analyze compounds contained in liquid samples (biological samples) derived from living organisms such as blood and urine. Biological samples contain various compounds in addition to the target compound to be analyzed, and pretreatment is performed to remove these compounds (for example, Patent Document 1). Pretreatment of biological samples includes processes such as adding a predetermined reagent to the biological sample to denature proteins and then introducing the sample into a filtering device to remove the denatured proteins.

[0003] Non-Patent Document 1 describes a pretreatment device having a function of automatically performing pretreatment of a plurality of liquid samples. In this device, a filtering container provided with a filter on its lower surface is attached to the upper opening of a collection container. Then, the liquid sample is introduced into the filtering container, and the internal space of the collection container is decompressed by a vacuum pump through an intake port to suction-filter the liquid sample. In this device, the user sets the suction filtration time in advance, and a plurality of liquid samples are sequentially suction-filtered for the set time.

[0004] Japanese Unexamined Patent Application Publication No. 2020-98173

[0005] "Fully Automated LC-MS Pretreatment Device Fully Automated Sample Preparation Module for LC-MS CLAM-2040", [online], November 2022, Shimadzu Corporation, [searched on January 16, 2025], Internet <URL:https: / / www.an.shimadzu.co.jp / sites / an.shimadzu.co.jp / files / pim / pim_document_file / an_jp / brochures / 20796 / c146-2274.pdf>

[0006] In the above-described apparatus, if the suction filtration time set by the user is shorter than the time required to filter the liquid sample, some of the liquid sample will remain in the filtration container. On the other hand, if the suction filtration time set by the user is longer than the time required to filter the liquid sample, the filter will gradually dry out after the liquid sample in the filtration container has been filtered, and air will flow into the recovery container through the filter, creating an airflow within the recovery container. As a result, the liquid sample in the recovery container will flow into the intake port, reducing the amount of liquid sample recovered and making analysis difficult, or reagents may evaporate, concentrating the liquid sample, or the intake port may become contaminated. Furthermore, because the composition and amount of compounds contained in biological samples are not uniform, even if the suction filtration time set by the user is suitable for suction filtration of one biological sample, it may not be suitable for suction filtration of another biological sample.

[0007] The problem that this invention aims to solve is to provide a technology that allows the suction filtration of a liquid sample to be analyzed to be terminated at an appropriate time.

[0008] The analytical sample filtration apparatus according to the present invention, which was developed to solve the above problems, comprises: a filtration container with a filter on its lower surface; a recovery container having an upper opening and an intake port to which the filtration container is attached; a depressurization mechanism for reducing the internal space of the recovery container via the intake port; a pressure measuring unit for measuring the pressure in the internal space of the recovery container; and a depressurization operation control unit which, when a predetermined input operation is performed, starts a depressurization operation of the internal space of the recovery container by the depressurization mechanism, and thereafter stops the depressurization operation of the internal space of the recovery container by the depressurization mechanism when the pressure measurement value or the amount of change of the measured value over time meets a predetermined standard.

[0009] Another aspect of the present invention is a program for controlling the operation of a filtration apparatus for analytical samples, comprising a filtration container with a filter on its lower surface, a recovery container having an upper opening and an intake port to which the filtration container is attached, a depressurization mechanism for reducing the internal space of the recovery container via the intake port, and a pressure measuring unit for measuring the pressure in the internal space of the recovery container, wherein the program causes a computer to operate as a control unit that, when a predetermined input operation is performed, starts the depressurization operation of the internal space of the recovery container by the depressurization mechanism, and thereafter stops the depressurization operation of the internal space of the recovery container by the depressurization mechanism when the pressure measurement value or the amount of change of the measured value over time meets a predetermined standard.

[0010] In a filtration device, if the pressure inside the recovery container is continuously reduced after the filtration of the liquid sample is complete, the filter gradually dries out, air flows into the recovery container, and the pressure inside the recovery container increases. In the filtration device and the program for the analytical sample filtration device according to the present invention, the pressure inside the recovery container is measured by the pressure measuring unit when filtering a liquid sample, and when the measured value of the pressure or the amount of change of the measured value over time meets a predetermined standard, the control unit stops the pressure reduction operation of the internal space of the recovery container by the pressure reduction mechanism. Therefore, regardless of the composition or amount of compounds contained in the liquid sample, the suction filtration of the liquid sample can be terminated at an appropriate timing.

[0011] A plan view showing the configuration of a pretreatment device having one embodiment of the filtration device according to the present invention. A diagram showing the structure of the recovery container in this embodiment. A diagram showing the structure of the filtration container in this embodiment. A diagram showing the structure of the pretreatment container in this embodiment. A diagram showing the pretreatment container in this embodiment attached to the filtration port. A diagram illustrating the configuration of the decompression mechanism in this embodiment. A graph showing an example of the time change of negative pressure in the recovery container during the filtration process of a liquid sample.

[0012] One embodiment of the analytical sample filtration apparatus according to the present invention will be described below with reference to the drawings.

[0013] Figure 1 is a plan view showing the main components of a sample pretreatment device 100 having a filtration device for analytical samples according to the present invention. The sample pretreatment device 100 of this embodiment has a configuration similar to the pretreatment device described in Patent Document 1, and includes a sample / reagent container table 50, a pretreatment container table 60, a sample dispensing probe 70, a reagent dispensing probe 80, and a transport arm 72. It also includes a control unit 90 that controls the operation of each of these parts. Furthermore, it includes a dispensing port 32 for dispensing liquid samples and reagents, a waste port 33, a washing port 34, a stirring unit 36 ​​having three stirring ports 361, and a temperature control unit 37 having three temperature control ports 371.

[0014] The sample / reagent container table 50 consists of two rotatable tables. The outer table has multiple concentrically arranged holes 51 for accommodating sample containers containing liquid samples. The inner table has holes 35 for accommodating reagent containers containing reagents. The pre-treatment container table 60 is also rotatable and has multiple concentrically arranged holes 61 for accommodating pre-treatment containers 10 (see Figure 4) used when pre-treating liquid samples. In addition, the pre-treatment container table 60 has two filtration ports 31 in the center, which are used when performing the filtration operation described later.

[0015] The sample dispensing probe 70 collects liquid samples from sample containers housed in the sample / reagent container table 50 and dispenses them into the filtration container 12 (see Figure 3) housed in the dispensing port 32. The underside of the tip of the sample dispensing probe 70 is provided with a probe for collecting and dispensing liquid samples, which is configured to be rotatable around a rotation axis 71 located at the base end and to be able to move up and down along the rotation axis 71.

[0016] The reagent dispensing probe 80 collects reagents from reagent containers housed in the sample / reagent container table 50 and dispenses them into the filtration container 12 housed in the dispensing port 32. The lower surface of the tip of the reagent dispensing probe 80 is provided with a probe for collecting and dispensing reagents, which is configured to be rotatable around a rotation axis 81 located at the base end and to be able to move up and down along the rotation axis 81.

[0017] The transport arm 72 moves the pre-treatment container 10, the recovery container 11 (see Figure 2), and the filtration container 12 to their respective locations. The lower tip of the transport arm 72 is provided with a handle for gripping each container, and is configured to rotate around a rotation axis 81 shared with the reagent dispensing probe 80, and to move up and down along the rotation axis 81.

[0018] The control unit 90 includes a storage unit 91. The storage unit 91 stores information regarding the content and sequence of pre-processing operations (dispensing liquid samples, dispensing reagents, stirring, filtration, heating, transport to the autosampler, etc.), the control of each part associated with these operations, and information regarding the criteria for the reduced pressure operation when performing the filtration process described later. The control unit 90 also has a pre-processing operation execution unit 92 and a reduced pressure operation control unit 93 as functional blocks. The control unit 90 is, for example, a general personal computer, and the above functional blocks are realized by executing a pre-installed program on the processor. Furthermore, the control unit 90 is connected to an input unit 96 consisting of a keyboard and mouse for performing appropriate input operations, and a display unit 97 consisting of a liquid crystal display for displaying appropriate information.

[0019] Next, the configuration of the pre-treatment container 10 will be described. The pre-treatment container 10 (see Figure 4) consists of a recovery container 11 (see Figure 2) with an open top and a filtration container 12 (see Figure 3) attached to the opening of the recovery container 11.

[0020] As shown in the cross-sectional view on the left side of Figure 2, the recovery container 11 is a member having a cylindrical shape with an open top and a gradually decreasing diameter at the bottom, and an extension portion 111 is formed on the side circumference. Also, as shown in the side view on the right side of Figure 2, notches 112 are formed in two places on the top (only one is shown). The inner diameter of the top opening of the recovery container 11 is slightly larger than the outer diameter of the main body of the filtration container 12 described later. Note that there may be one or two or more notches 112. The extension portion 111 is provided to facilitate gripping the recovery container 11 when moving the recovery container 11 with the transport arm 72, and a recovery container 11 without the extension portion 11 may also be used.

[0021] As shown in the cross-sectional view in Figure 3, the filtration container 12 is a member having a substantially cylindrical body with an open top. On the side circumference of the body, from the top (opening side), a first extension portion 121, a second extension portion 122, and a skirt portion 123 with a substantially L-shaped cross-section are formed in order. A cylindrical portion 124 with a diameter smaller than the diameter of the cylinder is formed at the bottom of the cylinder, and a filter 13 is attached to the bottom. The filter 13 physically or chemically separates the target substance contained in the liquid introduced into the filter 13, and an appropriate filter is used depending on the content of the pretreatment of the liquid sample. The first extension portion 121 and the second extension portion 122 are also provided to facilitate gripping the filtration container 12 when moving the filtration container 12 with the transport arm 72, and a filtration container 12 without the first extension portion 121 and the second extension portion 122 may also be used.

[0022] As shown in Figure 4, the pre-treatment container 10 is constructed by attaching the filtration container 12 to the upper opening of the recovery container 11. At this time, the extension portion 111 of the recovery container 11 is housed in the skirt portion 123 of the filtration container 12.

[0023] Figure 5 shows a cross-sectional view of the pre-treatment container 10 positioned in the filtration port 31. The filtration port 31 is a hole formed in the main body block 30 of the pre-treatment container table 60, and a leaf spring 32 is positioned inside it. When the pre-treatment container 10 is inserted into the filtration port 31, the bottom of the skirt portion 123 abuts against the upper surface of the main body block 30, and the side circumference of the pre-treatment container 10 is fixed in place, sandwiched by the leaf spring 32. An elastic ring-shaped sealing member 301 is provided on the upper surface of the main body block 30 at the position where the skirt portion 123 abuts, and the space below the skirt portion 123 is kept airtight by the bottom of the skirt portion 123 abutting against this sealing member 301. The main body block 30 is provided with an exhaust passage 41 (see Figure 6) that communicates with the filtration port 31.

[0024] As described above, the inner diameter of the upper opening of the recovery container 11 is slightly larger than the outer diameter of the main body of the filtration container 12, which will be described later, and a small gap 14 is formed between the inner surface of the recovery container 11 and the outer surface of the filtration container 12. Also, as described above, a notch 112 is formed in the upper part of the recovery container 11. These features form an exhaust path 15, which allows the internal space of the recovery container 11 to be depressurized.

[0025] Figure 6 schematically shows the configuration of the exhaust mechanism. The exhaust mechanism comprises, in order from the side of the main body block 30, an exhaust passage 41, an air filter 42, a connecting passage 43, and a vacuum pump 44. The air filter 42 has a dust removal filter 421 that removes dust contained in the air exhausted through the exhaust passage 41. The connecting passage 43 is provided with a filtration port valve 45 and a needle valve 46. A filtration port pressure sensor 47 is positioned between the air filter 42 and the filtration port valve 45, and a vacuum pump pressure sensor 48 is positioned between the needle valve 46 and the vacuum pump 44.

[0026] The filtration port valve 45 is a three-way valve and is used to switch the connection configuration of the connection channel 43 between a first connection state in which the recovery container 11 is connected to the vacuum pump, and a second state in which the channel between the recovery container 11 and the filtration port valve 45 is opened to the atmosphere and the channel connected to the vacuum pump 44 is closed.

[0027] The needle valve 46 is used to adjust the negative pressure inside the recovery container 11 by adjusting the opening of the connecting channel. In this embodiment, the opening of the needle valve 46 is adjusted so that the negative pressure inside the recovery container 11 is -50kPa.

[0028] The filtration port pressure sensor 47 is used to measure the pressure in the internal space of the recovery container 11 via the connecting passage 43, the air filter 42, and the exhaust passage 41. The vacuum pump pressure sensor 48 is used to measure the pressure in the connecting passage 43, which is closed by the filtration port valve 45 to form the second state described above, in the event of a malfunction in the vacuum pump 44.

[0029] Next, we will describe the filtering process of the liquid sample, which is a characteristic operation in this embodiment.

[0030] When filtering a liquid sample, a standard for reducing the pressure inside the recovery container 11 using a vacuum pump 44 is established in advance. In this embodiment, a standard of dp / dt ≥ 6 [kPa / s] is established for the change in pressure P inside the recovery container 11, as measured by the filtration port pressure sensor 47, and this standard is stored in the memory unit 91.

[0031] When filtering a liquid sample, the pre-treatment container 10, containing the liquid sample (with reagents added, stirred, and heated) in the filtration container 12, is placed in the filtration port 31. This process is included in the pre-treatment operations (dispensing of liquid sample, dispensing of reagents, stirring, filtration, heating, transport to autosampler, etc.) which are automatically performed under the control of the pre-treatment operation execution unit 92 based on information stored in the memory unit 91. Here, an example is described in which the pre-treatment operation execution unit 92 automatically performs a series of pre-treatment operations, but the user may perform each step of the pre-treatment operations themselves.

[0032] When the pre-treatment container 10 is set in the filtration port 31, the depressurization control unit 93 operates the vacuum pump 44 to reduce the pressure inside the recovery container 11 via the connecting channel 43, the air filter 42, and the exhaust channel 41. When the pressure inside the recovery container 11 is reduced, the liquid sample introduced into the filtration container 12 is gradually drawn from the filtration container 12 to the recovery container 11 through the filter 13. In parallel with this operation, the pressure inside the recovery container 11 is measured by the filtration port pressure sensor 47.

[0033] Here, the change in negative pressure inside the recovery container 11 when a liquid sample is filtered using a conventional method in the pretreatment apparatus of the above embodiment will be explained with reference to the example shown in Figure 7.

[0034] When the internal space of the recovery container 11 is depressurized, the negative pressure in the internal space reaches a preset pressure (a pressure determined according to the opening of the needle valve 46; in this example, -50 kPa) (point A). Thereafter, a nearly constant pressure is maintained while the liquid sample in the filtration container 12 passes through the filter 13 (points A to B).

[0035] As the liquid sample in the filtration container 12 moves through the filter 13 to the recovery container 11, the filter 13 gradually begins to dry, and air begins to flow into the recovery container 11 through the filter 13 (point B). Consequently, an airflow is generated in the internal space of the recovery container 11, and the liquid sample in the recovery container 11 begins to flow back through the exhaust path 15. After the backflow of the liquid sample occurs, the amount of air flowing into the recovery container 11 through the filter 13 and the amount of air exhausted by the vacuum pump 44 become equal, and a constant negative pressure is maintained again (from point C onward; however, this pressure is higher than the negative pressure adjusted by the opening of the needle valve 46). The time between point B and point C, during which the negative pressure is constant, is, for example, about 3 seconds, and backflow of the liquid sample may occur during this time. Note that the fluctuations in the negative pressure values ​​shown throughout the graph are due to the pulsation of the vacuum pump.

[0036] In conventional filtration processes, if the suction filtration time is longer than the time required to filter the liquid sample, the liquid sample in the recovery container 11 flows into the exhaust path 15, as described above. This can lead to problems such as a decrease in the amount of liquid sample recovered in the recovery container 11, making analysis difficult, contamination of the exhaust path 15, or concentration of the liquid sample due to evaporation of volatile components such as reagents. If the suction filtration time set by the user is shorter than the time required to filter the liquid sample, the above-mentioned backflow will not occur, but in that case, some of the liquid sample will remain in the filtration container 12 without being filtered.

[0037] Based on the problems that occurred in the prior art, in this embodiment, after the vacuum pump 44 starts operating, the vacuum pump 44 stops operating when the negative pressure in the internal space of the recovery container 11, as measured by the filtration port pressure sensor 47, changes (pressure rises) beyond a predetermined standard (dp / dt ≥ 6 [kPa / s] in this embodiment). In the graph of negative pressure change shown in Figure 7, the vacuum pump 44 stops operating when the negative pressure starts to rise beyond point B. This makes it possible to sufficiently filter the liquid sample in the filtration container 12 and recover it in the recovery container 11, while also preventing the liquid sample in the recovery container 11 from flowing back into the exhaust path 15.

[0038] The above embodiments are examples and can be modified as appropriate in accordance with the spirit of the present invention.

[0039] Although the above embodiment was described as a sample pretreatment device 100, the same configuration can be adopted for a filtration device for analytical samples incorporated into other analytical instruments.

[0040] In the above embodiment, the criterion was set to change (pressure increase) beyond dp / dt ≥ 6 [kPa / s], but this value is just an example and can be changed as appropriate. Generally, the fluctuation in the negative pressure value due to the pulsation of the vacuum pump is less than ±1 [kPa / s], so by setting dp / dt ≥ 1 [kPa / s], it is possible to avoid false detection of pump pulsation and stopping the operation of the vacuum pump 44. In addition, depending on the volume of the recovery container 11, the noise of the pressure sensor, etc., it may be preferable to set the above criterion higher. Even in such cases, backflow of the liquid sample can be prevented by setting the criterion value to 10 [kPa / s] or less.

[0041] Furthermore, in the above embodiment, the standard was determined by the change in the negative pressure value, but it may also be the absolute value of the negative pressure. In that case, the change in the negative pressure inside the recovery container 11 can be measured by preliminary experiments, etc., and the standard value can be determined based on the results. As shown in Figure 7, when the negative pressure changes, backflow of the liquid sample can be prevented by setting the pressure to a few kPa higher than the negative pressure determined by the opening of the needle valve 46 (for example, -48 kPa (the value of the negative pressure determined by the opening of the needle valve 46 + 2 kPa)). Furthermore, if the possibility of backflow of the liquid sample due to airflow in the internal space of the recovery container 11 is low, the concentration of the liquid sample due to volatilization of components contained in the liquid sample in the recovery container 11 (e.g., evaporation of reagents) can be avoided by setting the pressure to a few kPa lower than the negative pressure maintained after the negative pressure rises (for example, -42 kPa or less). Note that the numerical values ​​for the negative pressure or the amount of change in its value are examples, and an appropriate value may be determined as a standard by conducting preliminary experiments in the filtration device used for filtering the liquid sample. Note that although the standard was determined by negative pressure (relative pressure) above, the standard may also be determined by a pressure value.

[0042] In the above embodiment, the vacuum pump 44 is stopped when the negative pressure in the internal space of the recovery container 11 satisfies a predetermined standard. However, the decompression operation may be stopped by switching the filtration port valve 45 from the first state to the second state.

[0043] The configuration of the pretreatment container 10 in the above embodiment is an example, and the same configuration as above can be adopted in various filtration devices (devices that perform suction filtration) using a pretreatment device having an appropriate structure for decompressing the space for collecting the filtered liquid sample.

[0044] [Aspect] It is obvious to those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects.

[0045] (Item 1) A filtration device for an analytical sample according to an aspect of the present invention includes: a filtration container provided with a filter on the lower surface; a recovery container having an upper opening to which the filtration container is attached and an intake port; a decompression mechanism for decompressing the internal space of the recovery container through the intake port; a pressure measurement unit for measuring the pressure in the internal space of the recovery container; and a decompression operation control unit that starts the decompression operation of the internal space of the recovery container by the decompression mechanism when a predetermined input operation is performed, and then stops the decompression operation of the internal space of the recovery container by the decompression mechanism when the measured value of the pressure by the pressure measurement unit or the amount of change in the measured value over time satisfies a predetermined standard.

[0046] (Item 4) Another aspect of the present invention is a program for controlling the operation of a filtration device for an analytical sample, which includes a filtration container provided with a filter on the lower surface, a recovery container having an upper opening to which the filtration container is attached and an intake port, a decompression mechanism for decompressing the internal space of the recovery container through the intake port, and a pressure measurement unit for measuring the pressure in the internal space of the recovery container, and causes a computer to operate as a control unit that starts the decompression operation of the internal space of the recovery container by the decompression mechanism when a predetermined input operation is performed, and then stops the decompression operation of the internal space of the recovery container by the decompression mechanism when the measured value of the pressure by the pressure measurement unit or the amount of change in the measured value over time satisfies a predetermined standard.

[0047] In the filtration device, if the decompression in the recovery container is continued after the filtration of the liquid sample is completed, the filter gradually dries out, air flows into the recovery container, and the pressure in the recovery container increases. In the filtration device according to claim 1 and the program for the filtration device of the analytical sample according to claim 4, when filtering the liquid sample, the pressure in the recovery container is measured by the pressure measurement unit, and when the measured value of the pressure or the amount of change over time of the measured value satisfies a predetermined criterion, the control unit stops the decompression operation of the internal space of the recovery container by the decompression mechanism. Therefore, regardless of the composition and amount of the compound contained in the liquid sample, the suction filtration of the liquid sample can be terminated at an appropriate timing.

[0048] (Item 2) The filtration device of the analytical sample according to item 2 is the filtration device of the analytical sample according to item 1, wherein the predetermined criterion is that the amount of change over time of the measured value of the pressure exceeds a threshold value.

[0049] (Item 3) The filtration device of the analytical sample according to item 3 is the filtration device of the analytical sample according to item 2, wherein the threshold value is 1 kPa / s or more and 10 kPa / s or less.

[0050] In the filtration device of the analytical sample according to item 2, based on the fact that the amount of change over time of the measured value of the pressure has exceeded the threshold value, it can be detected that all of the liquid sample has been filtered and air has entered the recovery container through the filter, thereby suppressing the generation of an air flow in the internal space of the recovery container. As described in item 3, by setting the amount of change over time of the above-mentioned measured value to a value of 1 kPa / s or more, false detections such as pulsation of the vacuum pump included in the decompression mechanism and noise of the pressure sensor can be avoided. Also, by setting the amount of change over time of the above-mentioned measured value to 10 kPa / s or less, volatilization of the components in the liquid sample can be avoided.

[0051] 10...Pre-treatment container 100...Sample pre-treatment device 11...Collection container 111...Extension section 12...Filtration container 121...First extension section 122...Second extension section 123...Skirt section 124...Cylindrical section 13...Filter 14...Gap 15...Exhaust path 30...Main body block 301...Sealing member 31...Filtration port 32...Dispensing port 33...Disposal port 34...Washing port 35...Hole for accommodating reagent containers 36...Agitation section 361...Agitation port 37...Temperature control section 371...Temperature control port 41...Exhaust path 42...Air filter 421...Dust removal filter 43...Connection path 44...Vacuum pump 45...Filtration port valve 46...Needle valve 47...Filtration port pressure sensor 48...Vacuum pump pressure sensor 50...Table for sample / reagent containers 51...Hole for accommodating sample containers 60... Table for pre-treatment container 61... Hole for accommodating pre-treatment container 70... Probe for sample dispensing 71... Rotating axis 72... Transport arm 80... Probe for reagent dispensing 81... Rotating axis 90... Control unit 91... Memory unit 92... Pre-treatment operation execution unit 93... Reduced pressure operation control unit 96... Input unit 97... Display unit

Claims

1. A filtration apparatus for analytical samples, comprising: a filtration container with a filter on its lower surface; a recovery container having an upper opening and an intake port to which the filtration container is attached; a depressurization mechanism for reducing the internal space of the recovery container via the intake port; a pressure measuring unit for measuring the pressure in the internal space of the recovery container; and a depressurization operation control unit which, when a predetermined input operation is performed, starts a depressurization operation of the internal space of the recovery container by the depressurization mechanism, and thereafter stops the depressurization operation of the internal space of the recovery container by the depressurization mechanism when the pressure measurement value or the amount of change of the measured value over time meets a predetermined standard.

2. The analytical sample filtration apparatus according to claim 1, wherein the predetermined standard is that the amount of change over time of the measured pressure exceeds a threshold.

3. The analytical sample filtration apparatus according to claim 1, wherein the threshold is 1 kPa / s or more and 10 kPa / s or less.

4. A program for controlling the operation of a filtration apparatus for analytical samples, comprising a filtration container with a filter on its lower surface, a recovery container having an upper opening and an intake port to which the filtration container is attached, a depressurization mechanism for reducing the internal space of the recovery container via the intake port, and a pressure measuring unit for measuring the pressure in the internal space of the recovery container, wherein the program causes a computer to operate as a control unit that, when a predetermined input operation is performed, starts the depressurization operation of the internal space of the recovery container by the depressurization mechanism, and thereafter stops the depressurization operation of the internal space of the recovery container by the depressurization mechanism when the pressure measurement value or the amount of change of the measured value over time meets a predetermined standard.

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