LIQUID SAMPLING METHOD IN FLOW MONITORING SYSTEM

A liquid sampling method in a flow monitoring system including a sampling section having a needle for performing sampling of a liquid, an analysis section that performs analysis of the liquid sampled by the sampling section, and a fluid supply section that supplies a sample fluid in a state of gas-liquid two-phase flow containing a gas phase and a liquid phase with the sample remaining in the state of gas-liquid two-phase flow. The liquid sampling method includes: a storage step of storing, in the storage container, a liquid phase contained in the sample fluid; a separation step of separating, from a liquid phase, a gas phase contained in the liquid phase stored in the storage container; and an injection step of suctioning, as a sample, the liquid phase stored in the storage container from a distal end of the needle after the separation step and injecting a predetermined amount of the sample into the analysis section through the injection port.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid sampling method in a flow monitoring system.

2. Description of the Related Art

A chromatograph is often used for monitoring of reaction treatment. In that case, the fluid during the reaction treatment is supplied to a flow vial, and the fluid flowing inside the flow vial is collected by a needle, injected into an analysis flow path of the chromatograph, and analyzed by the chromatograph (see WO 2019/038928).

In flow synthesis, which is one field of organic synthesis, a reaction may be performed in a gas-liquid system in which a gas such as hydrogen and a liquid such as an aromatic hydrocarbon are mixed with a synthetic material, and in this case, the gas of the material may remain without reacting (see Polysilane-Immobilized Rh—Pt Bimetallic Nanoparticles as Powerful Arene Hydrogenation Catalysts: Synthesis, Reactions under Batch and Flow Conditions and Reaction Mechanism). A gas may be contained as a reaction product. In such a case, a sample containing a reaction product becomes a gas-liquid two-phase flow containing a gas phase and a liquid phase. When monitoring of such reaction product is performed, it is difficult to accurately sample a desired amount of liquid phase from the gas-liquid two-phase flow flowing through a flow vial with a needle in a chromatograph designed on the premise of handling a liquid. Therefore, a gas-liquid separation mechanism for separating the gas phase and the liquid phase is installed upstream of the flow vial, and only the liquid phase is introduced into the flow vial, whereby a desired amount of the liquid phase can be accurately sampled.

SUMMARY OF THE INVENTION

While various gas-liquid separation mechanisms exist, any of the mechanisms has problems that an internal capacity is large, a delay time until the sample reaches the flow vial occurs, which makes it difficult to perform accurate monitoring, carryover easily occurs because a reaction product tends to remain in the mechanism, and the flow rate does not become constant due to intermittent discharge.

The present invention has been made in view of the above problems, and an object thereof is to enable accurate sampling of a desired amount of liquid phase from a fluid in a state of gas-liquid two-phase flow without using a gas-liquid separation mechanism.

A liquid sampling method according to the present invention is a liquid sampling method in a flow monitoring system, wherein the flow monitoring system includes a sampling section having a needle for performing sampling of a liquid and a storage container, an analysis section that performs analysis of the liquid sampled by the sampling section, and a fluid supply section that supplies a sample fluid in a state of gas-liquid two-phase flow containing a gas phase and a liquid phase with the sample remaining in the state of gas-liquid two-phase flow, the liquid sampling method including:a storage step of collecting a predetermined amount of the sample fluid flowing through the liquid supply section and storing the collected sample fluid in the storage container;a separation step of separating a gas phase contained in the sample fluid stored in the storage container from a liquid phase; andan injection step of suctioning the liquid phase stored in the storage container from a distal end of the needle after the separation step and injecting a predetermined amount of the liquid phase as a sample into the analysis section through the injection port.

The liquid sampling method according to the present invention enables sampling, as a sample, a predetermined amount of a liquid phase without providing a flow monitoring system with a gas-liquid separation mechanism by, in sampling, after storing the sample fluid supplied from the fluid supply section in the storage container and separating a gas phase contained in the sample fluid from a liquid phase in the storage container, suctioning, with the needle, the liquid phase stored in the storage container as a sample, and injecting a predetermined amount of the sample into the analysis section.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an example of a liquid sampling method according to the present invention will be described with reference to the drawings.

A flow monitoring system1that executes the liquid sampling method mainly includes a flow synthesis device2and an analysis device4. The flow synthesis device2constitutes a fluid supply section that supplies the analysis device4with a sample fluid in a state of gas-liquid two-phase flow containing a gas phase and a liquid phase.

The flow synthesis device2is a device that supplies two types of fluids to a reactor10by two pumps6and8, and reacts the two types of fluids in the reactor10to obtain a reaction product. One of the two types of fluids supplied to the reactor10by the pumps6and8is a liquid and the other is a gas. The reaction product obtained in the reactor10flows through an outlet flow path36of the reactor10in a state of gas-liquid two-phase flow. The outlet flow path36is branched into flow paths38and40, and a part of the reaction product flowing out of the reactor10is supplied as a sample fluid to a flow vial26described later through the flow path38in a state of gas-liquid two-phase flow.

The analysis device4includes a sampling section12, an analysis section14, a liquid feeding pump16, and a control device18. The sampling section12injects, into the analysis section14, a liquid phase in a sample fluid supplied from the flow synthesis device2. The analysis section14performs analysis of the sample injected by the sampling section12. The control device18performs operation management of the analysis device4. The liquid feeding pump16feeds a mobile phase toward the analysis section14through an analysis flow path20.

The sampling section12includes a needle22, a syringe pump24, the flow vial26, an injection port28, and a storage container30.

The needle22is for performing suctioning and dispensing of a fluid from a distal end. The needle22moves three-dimensionally in a state where the distal end faces vertically downward, and can access the flow vial26, the injection port28, and the storage container30.

The syringe pump24is provided so as to be fluidly connected to the needle22, and can perform suctioning and discharging of a fluid through the needle22.

The flow vial26is provided so that the needle22can access an internal space from above. A side surface of the flow vial26is provided with an inlet for causing a sample fluid to flow into an internal space and an outlet for causing the sample fluid to flow out from the internal space, and the sample fluid supplied through the flow path38constantly flows in the internal space of the flow vial26in a state of gas-liquid two-phase flow.

The injection port28is for injecting a sample from the needle22into the analysis section14. The injection port28is configured to receive the distal end of the needle22to enable fluid connection of the needle22. The sample injected from the needle22through the injection port28is guided to the analysis section14together with the mobile phase flowing through the analysis flow path20.

The storage container30is a container of an open top surface in which the needle22can access from above. In this example, a plurality of the storage containers30are provided.

The analysis section14includes a separation column32and a detector34. The separation column32is provided on the analysis flow path20and is for separating components in the sample injected into the mobile phase through the injection port28by the sampling section12from each other. The detector34is provided downstream of the separation column32on the analysis flow path20, and is for detecting each component separated by the separation column32.

The control device18is implemented by a computer device including a central processing section (CPU) and an information storage device, such as a personal computer. The control device18includes a controller42, an information storage section44, and an arithmetic section46. The controller42and the arithmetic section46are functions implemented by the CPU executing software. The information storage section44is a function implemented by a part of storage area of the information storage device.

The controller42is configured to control the operation of the sampling section12to execute sampling of the sample fluid supplied from the flow synthesis device2to the flow vial26. In sampling, a storage step of storing, into the storage container30, a liquid phase in a sample fluid by performing, one time or more, a storage operation of collecting and dispensing, into the storage container30, the sample fluid from the flow vial26, and an injection step of injecting, into the analysis section14through the injection port28, as a sample, a liquid layer stored in the storage container30in the storage step are executed. A specific operation of the sampling will be described later.

The information storage section44stores information necessary for execution of the sampling. The information necessary for execution of the sampling includes an internal capacity of the syringe pump24(the maximum volume of the fluid that can be suctioned at one time), a gas-liquid mixing rate that is the volume percent between the gas phase and the liquid phase contained in the sample fluid supplied from the flow synthesis device2, and an injection amount of the sample into the analysis section14. These pieces of information can be input in advance by the user.

The arithmetic section46is configured to calculate the times of storage operation to be executed in the storage step described above using the information stored in the information storage section44. When the gas-liquid mixing rate, which is the ratio of the gas phase and the liquid phase contained in the sample fluid supplied from the flow synthesis device2, is large (the ratio of the gas phase is high), it is considered that a liquid phase of an amount to be injected into the analysis section14as a sample cannot be stored in the storage container30by one time of storage operation depending on the internal capacity of the syringe pump24. Therefore, from the relationship among the gas-liquid mixing rate of the sample fluid supplied from the flow synthesis device2, the internal capacity of the syringe pump24, and the injection amount of the sample into the analysis section14, the arithmetic section46calculates the times of storage operation necessary for storing, into the storage container30, a liquid phase equal to or greater than the injection amount of the sample into the analysis section14. The controller42executes, during the storage step, the storage operation the flow path calculated by the arithmetic section46.

Note that the arithmetic section46is not an essential function. The times of storage operation to be executed in the storage step may be configured to be preset by the user. In that case, the controller42executes, during the storage step, the storage operation the flow path set in advance by the user.

An example of a liquid sampling method in the flow monitoring system will be described with reference to the flowchart ofFIG.2.

When the time to execute sampling comes, the controller42inserts the distal end of the needle22into the flow vial26in a state where the syringe pump24is fluidly connected to the needle22(step101), and causes the syringe pump24to suction, from the distal end of the needle22, the sample fluid flowing through the flow vial26(step102). Thereafter, the controller42pulls out the needle from the flow vial26, moves the needle22to a position above the storage container30that is empty, and stores the suctioned sample fluid in the storage container30(step103). After the sample fluid is stored in the storage container30, the sample fluid is held in the storage container30for a certain period of time, whereby the gas phase is separated from the liquid phase of the sample fluid (step104). The sample fluid suctioned from the flow vial26contains a gas phase and a liquid phase, and if the sample fluid is stored in the storage container30of an open top surface, the gas phase contained in the dispensed sample fluid escapes above the liquid phase, and only the liquid phase is stored in a bottom part of the storage container30.

Steps101to104described above are one time of storage operation. The controller42causes the sampling section12to repeatedly execute the storage operation the flow path calculated in advance by the arithmetic section46or the flow path set in advance by the user (step105), and stores, in the storage container30, a liquid phase of a predetermined amount or more to be injected as a sample into the analysis section14.

After causing the sampling section12to execute the storage operation a predetermined flow path (step105: Yes), the controller42causes the distal end of the needle22to access the liquid phase stored in the storage container30, and causes the syringe pump24to suction, from the storage container30, a liquid phase of a predetermined amount to be injected into the analysis section14or greater than the predetermined amount (step106). Thereafter, the controller42fluidly connects the distal end of the needle22to the injection port28, and injects a predetermined amount of liquid phase as a sample into the mobile phase flowing through the analysis flow path20(step107).

The above sampling is set to be automatically executed when a preset time comes. When a plurality of times of sampling are automatically executed, the plurality of empty storage containers30having been prepared can be used in sequence for each sampling. Note that the present invention is not limited to this, and includes an aspect in which one storage container30is washed and repeatedly used. In that case, in addition to the mechanism that supplies a cleaning liquid to the storage container30, a mechanism that discharging the used liquid from the storage container30to a drain is provided.

In the above example, sampling of the sample fluid is performed using the flow vial26, but the present invention is not limited to this, and includes performing sampling of the sample fluid without using the flow vial26.

FIG.3shows an example of the configuration of a sampling section for executing a liquid sampling method without using a flow vial.

The sampling section12‘shown in the example ofFIG.3includes a multi-port valve50, which is a flow path switching section. Each port of the multi-port valve50is fluidly connected with the needle22, the syringe pump24, the flow path38through which a sample fluid from the flow synthesis device2flows, and a flow path leading to the drain. The needle22is fluidly connected selectively to any one of the flow path38and the syringe pump24by the multi-port valve50. At the time of sampling, the needle22is fluidly connected to the flow path38by the multi-port valve50, the sample fluid supplied from the flow synthesis device2through the flow path38is dispensed into the storage container30, and the liquid phase in the sample fluid is stored as a sample in the storage container30. Thereafter, the multi-port valve50is switched so that the syringe pump24is fluidly connected to the needle22, and the sample stored in the storage container30is suctioned through the needle22by the syringe pump24and injected into the mobile phase flowing through the analysis flow path20through the injection port28.

The example described above is merely an example of an embodiment of a flow monitoring system according to the present invention. The embodiment of the flow monitoring system according to the present invention is as follows.

One embodiment of a liquid sampling method according to the present invention is a liquid sampling method in a flow monitoring system, wherein the flow monitoring system includes a sampling section having a needle for performing sampling of a liquid and a storage container, an analysis section that performs analysis of the liquid sampled by the sampling section, and a fluid supply section that supplies a sample fluid in a state of gas-liquid two-phase flow containing a gas phase and a liquid phase with the sample remaining in the state of gas-liquid two-phase flow,the liquid sampling method including:a storage step of collecting and storing, in the storage container, a predetermined amount of the sample fluid flowing through the liquid supply section;a separation step of separating a gas phase contained in the sample fluid stored in the storage container from a liquid phase; andan injection step of suctioning the liquid phase stored in the storage container from a distal end of the needle after the separation step and injecting a predetermined amount of the liquid phase as a sample into the analysis section through the injection port.

In an aspect [1] of the one embodiment,the sampling section may further includea syringe pump provided so as to be fluidly connected to the needle and for perform suctioning and dispensing of a fluid through the needle, anda flow vial having an inlet for causing a fluid to flow into an internal space and an outlet for causing the fluid to flow out from the internal space, and configured to be accessible to the internal space by the needle, andin the storage step, a liquid phase contained in the sample fluid may be stored in the storage container by executing, at least one time, a storage operation of causing the needle to access the internal space of the flow vial, suctioning the sample fluid flowing through the flow vial from a distal end of the needle by the syringe pump, and storing, from the distal end of the needle into the storage container, the sample fluid suctioned.

The aspect [1] may further includea storage times calculation step of calculating a times of storage operation to be executed during the storage step in order to store, in the storage container, the liquid phase of the predetermined amount or more using a gas-liquid mixing rate and a capacity of the syringe pump, wherein the gas-liquid mixing rate is a ratio between the liquid phase and the gas phase contained in the fluid supplied to the internal space of the flow vial, whereinin the storage step, the storage operation may be repeated for a flow path calculated in the storage times calculation step. Such aspect can reliably store, in the storage container, a liquid phase of an amount to be injected as a sample into the analysis section, and can improve reproducibility of analysis.

Here, as the gas-liquid mixing rate, input by the user may be received.

In an aspect [2] of one embodiment, the analysis section (14) includesa separation column for separating, from each other, components contained in the sample injected through the injection port, anda detector for detecting each of the components separated from each other by the separation column.

In an aspect [3] of one embodiment, the sampling section may further includea syringe pump provided so as to be fluidly connected to the needle and for perform suctioning and dispensing of a fluid through the needle, anda flow path switching section, andin the storage step, the needle may be caused to be in fluid communication with the fluid supply section via the flow path switching section, and a liquid phase contained in the sample fluid may be stored in the storage container as a sample.

In the above aspect [3], the flow path switching section may be configured to selectively connect the needle to either the sample supply section or the syringe pump,the flow path switching section may fluidly connect the needle and the fluid supply section in the storage step, andthe flow path switching section may fluidly connect the needle and the syringe pump in the injection step.

DESCRIPTION OF REFERENCE SIGNS