JPWO2016088252A1 - Sample recovery mechanism and supercritical fluid apparatus equipped with the sample recovery mechanism - Google Patents

Abstract

The sample recovery mechanism has a recovery container that recovers fluid that has passed through the pressure control valve on the downstream side of the pressure control valve, and a pipe that connects the pressure control valve and the recovery container, and has passed through the pressure control valve. And a fluid introduction part that guides the fluid to a recovery container at a temperature at which a modifier in the fluid exists as a liquid.

Description

  The present invention relates to a sample recovery mechanism for recovering a sample from a fluid flowing out from a device using a supercritical fluid such as a supercritical fluid chromatograph device, and a supercritical fluid device including the sample recovery mechanism.

  In recent years, supercritical fluid chromatography (hereinafter referred to as SFC) has attracted attention. The SFC is a chromatographic apparatus that uses carbon dioxide or the like as a supercritical fluid by applying a certain temperature and pressure, and uses the supercritical fluid as a solvent. Supercritical fluids have both liquid and gas properties and are characterized by being more diffusive and less viscous than liquids. By using such a supercritical fluid as a solvent, analysis at high speed, high separation, and high sensitivity becomes possible.

Carbon dioxide generally used in SFC has a critical pressure of 7.38 MPa, a critical temperature of 31.1 ° C., which is relatively close to room temperature, has no flammability or chemical reactivity, and has high purity at low cost. It is most commonly used for SFC because it is available. Supercritical carbon dioxide (SCCO ₂ ) has low-polarity properties close to hexane, and the polarity of the mobile phase can be greatly changed by adding a polar organic solvent such as methanol as a modifier. In order to keep the solvent in a supercritical state, it is necessary to keep the pressure in the flow path system high. For this reason, the SFC is provided with a pressure control valve called a back pressure regulator (BPR) downstream of the separation column and detector in order to keep the flow path system at a constant pressure.

  In the preparative SFC or SFE, in order to collect the sample dissolved in the mixed fluid of carbon dioxide and the modifier, the fluid flowing out from the analysis flow path is collected. Since carbon dioxide has no dissolving power, almost all of the sample components are dissolved in the modifier. Therefore, all the sample components can be recovered by recovering the portion corresponding to the modifier in the fluid flowing out from the analysis flow path.

WO2008 / 011416 JP 2010-78532 A

  The fluid that has passed through the BPR is depressurized to atmospheric pressure, and carbon dioxide in the supercritical state or liquid state is vaporized after passing through the BPR. Therefore, the fluid flowing out from the outlet of the analysis channel is separated into a gas phase and a liquid phase. If only the liquid phase is taken out, the modifier in which the sample components are dissolved can be recovered.

  Conventionally, various sample recovery mechanisms for recovering only the liquid phase by separating the fluid flowing out from the analysis flow path into a gas phase and a liquid phase have been proposed (see, for example, Patent Document 1 and Patent Document 2). ). The conventional sample recovery mechanism is arranged so that the outlet of the fluid from the analysis channel is along the inner wall surface of the recovery container or gas-liquid separation container, and the droplet component in the fluid flowing out from the outlet is It is comprised so that it may flow down with dead weight along an inner wall surface, and a gaseous component may be discharged | emitted from the upper part of the container.

  However, the modifier in the fluid flowing out from the analysis channel is aerosolized due to volume expansion accompanying the vaporization of carbon dioxide. The liquid in the form of an aerosol has a large surface area and is easily evaporated. Since the evaporated liquid component is the same size as the gas and cannot be physically distinguished, gas-liquid separation using the weight of the droplet is impossible as before, and the evaporated liquid component is discharged to the outside together with carbon dioxide. As a result, the sample recovery rate decreases.

  In view of the above, an object of the present invention is to increase the recovery rate of the liquid phase in the fluid flowing out from the analysis flow path.

  The sample recovery mechanism according to the present invention recovers the liquid phase by separating the fluid flowing out from the analysis flow path of the supercritical fluid device into a gas phase and a liquid phase. The sample recovery mechanism has a recovery container that recovers the fluid that has flowed out of the analysis flow path, and a pipe that connects between the outlet of the analysis flow path and the recovery container, and a modifier in the fluid that is introduced into the recovery container And a fluid introduction part that leads to a recovery container at a temperature at which the liquid exists.

  In a supercritical fluid device, piping due to the generation of dry ice and coagulation of the modifier at the outlet of the pressure control valve due to the heat of vaporization of carbon dioxide in the fluid that has passed through the pressure control valve that controls the back pressure of the analysis channel Since there is a concern about clogging, etc., measures such as heating the piping on the outlet side of the pressure control valve by a heating unit such as a heater are generally taken. However, if the piping is heated on the rear side of the pressure control valve, evaporation of the aerosolized modifier passes through the pressure control valve, and if the fluid is introduced as it is to the collection container, it evaporates. A part of the modifier is discharged to the outside of the collection container together with carbon dioxide, and the sample component recovery rate is lowered. As in Patent Document 1 and Patent Document 2, proposals have been made for a method for growing and recovering an aerosol-modified modifier by passing through a pressure control valve. However, evaporation of an aerosolized modifier is conventionally performed. No proposal has been made on how to prevent the loss caused by.

  The fluid introduction part in the sample recovery mechanism of the present invention may or may not be provided with a heating part on the rear side of the pressure control valve (between the outlet of the analysis channel and the recovery container). In this case, the fluid flowing out from the analysis flow path is led to the collection container at a temperature at which the modifier exists as a liquid. Here, the temperature at which the modifier exists as a liquid is, for example, 20 ° C. or less.

  The inventors conducted experiments on the temperature of the fluid that passed through the pressure control valve and the recovery rate of the modifier. In such an experiment, a heating part for heating the pipe is provided on the rear stage side of the pressure control valve of the supercritical fluid device, and (1) when the set temperature of the heating part is 20 ° C., (2) the set temperature of the heating part is 60 ° C. (3) The modifier (methanol) when the set temperature of the heating section is set to 60 ° C. and cooled to about −25 ° C. by blowing cooling carbon dioxide to the pipe downstream of the heating section. ) Recovery rate. As a result of the experiment, (1) the recovery rate when the set temperature of the heating unit was 20 ° C. was 81.7%, whereas (2) the recovery rate when the set temperature of the heating unit was 60 ° C. Was 76.7%, and the recovery rate decreased when the set temperature of the heating part was increased. On the other hand, (3) when the set temperature of the heating part was set to 60 ° C. and the piping downstream of the heating part was cooled to about −25 ° C., a recovery rate of 93.3% was obtained. From these experimental results, it has been found that the temperature of the fluid flowing out from the analysis flow channel greatly affects the recovery rate of the modifier. The present invention has been made based on such knowledge.

  The present inventors have also found that the generation of dry ice and the solidification of the modifier hardly occur even if a heating part is not provided on the rear side of the pressure control valve. Therefore, in the present invention, it is not necessary to provide a heating part on the rear stage side of the pressure control valve. Since the modifier in the fluid that has passed through the pressure control valve is cooled by the heat of vaporization of carbon dioxide, the modifier is sufficient by the heat of vaporization of carbon dioxide if the flow rate of carbon dioxide is a certain amount (for example, 10 ml / min) or more. It is not necessary to separately provide a cooling mechanism for cooling the modifier to a liquid state. That is, the sample introduction part of the present invention is a case where no heating part is provided on the rear side of the pressure control valve, and the modifier is sufficiently cooled by the heat of vaporization of carbon dioxide and the modifier is in a liquid state. In the case where the conditions guided to the recovery container are applied, the condition including only the pipe connected between the pressure control valve and the recovery container is included.

  The modifier may not be sufficiently cooled only by the heat of vaporization of carbon dioxide depending on conditions such as when the flow rate of carbon dioxide is small (for example, 10 ml / min or less). It is preferable to provide a cooling means for cooling the section. If a cooling means for cooling a section upstream of the collection container is provided, it is possible to further promote the droplet formation of the modifier in the fluid flowing into the collection container. The recovery efficiency of the sample components can be improved.

  As an example of the cooling means, there may be mentioned one having a Peltier element and a portion cooled by the Peltier element coming into contact with one section of the pipe to cool the section.

  Another example of the cooling means is a low-temperature thermostatic chamber that has a space for accommodating a section of piping and maintains the interior of the space at a cooling temperature.

  Still another example of the cooling means is one that blows carbon dioxide for cooling on a section of piping.

  Still another example of the cooling means is an orifice portion in which an inner diameter of the pipe is narrowed to be smaller than other portions of the pipe. If an orifice part is provided between the pressure control valve and the recovery container, the pressure between the pressure control valve and the orifice part is maintained at a certain level, and carbon dioxide in the fluid that has passed through the pressure control valve is retained. It will not vaporize until it passes through the orifice. When the fluid in such a state passes through the orifice portion, the pressure of the fluid rapidly decreases, whereby carbon dioxide is vaporized, the fluid temperature decreases, and evaporation of the modifier in the fluid is suppressed. Thereby, the loss of the sample component due to the evaporation of the modifier is suppressed, and the recovery efficiency of the sample component in the fluid flowing out from the analysis channel is improved.

  The supercritical fluid device according to the present invention includes an analysis channel through which a mixed fluid of carbon dioxide and a modifier flows as a mobile phase, a sample introduction unit for introducing a sample into the analysis channel, and a sample introduction unit on the analysis channel. A separation column that is provided on the downstream side and separates the sample introduced from the sample introduction part into components, and a detection that is provided further downstream of the separation column on the analysis flow path and detects the sample components separated by the separation column. A pressure control valve that controls the pressure in the analysis flow path to a pressure at which the mobile phase becomes a supercritical state downstream from the detector of the analysis flow path, and the mobile phase that has passed through the pressure control valve is recovered And a sample recovery mechanism according to the present invention.

  In a preferred embodiment of the supercritical fluid device of the present invention, the sample recovery mechanism includes a plurality of recovery containers, and any one of these recovery containers can be selectively connected to the outlet of the analysis channel. A flow path switching valve configured as described above, so that the outlet of the analysis flow path is connected to a desired recovery container while the fluid containing the sample to be collected flows out of the analysis flow path. A control unit for controlling the switching operation of the flow path switching valve based on the detection signal is further provided. Thereby, the sample component isolate | separated with the separation column can be automatically collect | recovered to a separate collection container.

  In the supercritical fluid device of the present invention, the flow rate of carbon dioxide is 10 ml / min or more, and the heating mechanism for heating the fluid that has passed through the pressure control valve is not provided between the pressure control valve and the sample recovery mechanism. The sample recovery mechanism may not be provided with a cooling means for cooling the fluid. If the flow rate of carbon dioxide is 10 ml / min or more, the fluid is sufficiently cooled by the heat of vaporization of carbon dioxide when passing through the pressure control valve to suppress the evaporation of the modifier. A sufficiently high recovery rate can be obtained.

  A temperature sensor that detects the temperature of the fluid guided to the recovery container by the sample recovery mechanism may be further provided. If it does so, it can be checked whether the temperature of the fluid guide | induced to a collection | recovery container is the temperature which a modifier exists in a liquid.

  The sample recovery mechanism of the present invention has a recovery container that recovers fluid that has passed through the pressure control valve on the downstream side of the pressure control valve, and a pipe that connects the pressure control valve and the recovery container. And a fluid introduction part that guides the fluid that has passed through the recovery container to a temperature at which the modifier in the fluid exists as a liquid, so that evaporation of the modifier in the fluid that has passed through the pressure control valve is suppressed. The recovery rate of sample components is improved.

  Since the supercritical fluid device of the present invention includes the sample recovery mechanism of the present invention, disappearance due to evaporation of the modifier is suppressed, and a high sample recovery rate can be obtained.

It is a flow-path block diagram which shows one Example of the supercritical fluid apparatus provided with the sample collection mechanism. It is a schematic block diagram which shows one Example of a sample collection | recovery mechanism. It is a schematic block diagram which shows the other Example of a sample collection | recovery mechanism. It is a schematic block diagram which shows the further another Example of a sample collection | recovery mechanism. It is sectional drawing which shows an example of the structure of the fluid introduction flow path which has an orifice. It is sectional drawing which shows the other example of the structure of the fluid introduction flow path which has an orifice part. It is sectional drawing which shows the further another example of the structure of the fluid introduction flow path which has an orifice part. It is a flow-path block diagram (with an orifice part) which shows the structure of the experimental apparatus for verifying the relationship between fluid temperature and a recovery rate. It is a flow-path block diagram (no orifice part) which shows the structure of the experimental apparatus for verifying the relationship between fluid temperature and a recovery rate. It is a graph which shows the relationship between fluid temperature and modifier recovery. It is a graph which shows the relationship between fluid temperature and sample collection rate. It is a graph which shows the influence of the carbon dioxide flow rate with respect to a methanol recovery rate. It is a schematic block diagram which shows one Example of the sample collection | recovery mechanism provided with the function to detect the temperature of the modifier which passed the cooling mechanism. It is a schematic block diagram which shows the other Example of the sample collection | recovery mechanism provided with the function to detect the temperature of the modifier which passed the cooling mechanism. It is a schematic block diagram which shows the further another Example of the sample collection | recovery mechanism provided with the function to detect the temperature of the modifier which passed the cooling mechanism.

  An embodiment of a supercritical fluid device having a sample recovery mechanism will be described with reference to FIG.

  A carbon dioxide feed passage 2 for feeding liquid state carbon dioxide 8 by a pump 6 and a methanol feed passage 4 for feeding methanol 12 as a modifier by a pump 10 are connected to a mixer 14. An analysis flow path 16 is connected to the mixer 14. On the analysis channel 16, a sample injection unit 18 such as an autosampler, a separation column 20, a detector 22, and a pressure control valve 24 for injecting a sample into the analysis channel 16 are arranged in this order from the mixer 14 side. Yes. The detector 22 is, for example, an ultraviolet detector. A sample recovery mechanism 26 is connected to the flow path on the outlet side of the pressure control valve 24 (the outlet of the analysis flow path 16), and the sample component flowing out from the analysis flow path 16 is recovered by the sample recovery mechanism 26. ing.

  Carbon dioxide and methanol are mixed by the mixer 14 and introduced into the analysis channel 16 as a mobile phase. The carbon dioxide feed channel 2, the methanol feed channel 4, and the mixer 14 constitute a mobile phase feeding unit. The analysis flow path 16 is controlled to have an internal pressure of 7 MPa or more by the pressure control valve 24, and the mobile phase introduced into the analysis flow path 16 is in a supercritical fluid state. The sample injected by the sample injection unit 18 is transported to the separation column 20 by the mobile phase that has become a supercritical fluid, separated for each component, and detected by the detector 22. The sample component detected by the detector 22 flows out of the analysis channel 16 through the pressure control valve 24 together with the mobile phase, and is recovered by the sample recovery mechanism 26.

  The sample recovery mechanism 26 is controlled by a control unit 28. The control unit 28 is realized by a computer. The computer can be realized by, for example, a dedicated computer of a supercritical fluid device to which the sample recovery mechanism is applied or a general-purpose personal computer. The control unit 28 is configured to capture the detection signal of the detector 22 and control the sample recovery mechanism 26 based on the detection signal to recover the liquid containing the target sample component.

  The pumps 6 and 10 may independently perform drive control so that the liquid supply flow rate becomes a set flow rate, or may be a dedicated computer such as a system controller that controls the entire supercritical fluid device or The drive may be controlled by a general-purpose personal computer.

  A first embodiment of the sample recovery mechanism will be described with reference to FIG.

  In the sample recovery mechanism 26 </ b> A, the downstream end of the analysis flow path 16 is connected to the common port of the switching valve 30. The switching valve 30 has a plurality of selection ports, and can selectively connect between a common port to which the analysis flow path 16 is connected and any one selection port.

  A drain 17 for discharge is connected to one selection port of the switching valve 30, and a fluid introduction flow path 32 is connected to each of the remaining plurality of selection ports. The fluid introduction channel 32 communicates with the recovery container 34. In this embodiment, four collection containers 34 are connected to the switching valve 30, but any number of collection containers 34 may be used.

  This sample recovery mechanism 26A is based on the detection signal obtained by the detector 22 (see FIG. 1) at the timing when the fluid containing the sample component separated by the separation column 20 flows out from the outlet of the analysis channel 16. Any one collection container 34 is connected to the outlet of the analysis flow path 16. In the recovery container 34, methanol (modifier) in the fluid flowing out from the analysis flow path 16 is recovered as a liquid. When the sample component is not contained in the fluid flowing out from the analysis channel 16, the outlet of the analysis channel 16 is connected to the drain 17 and discharged.

  Carbon dioxide in the fluid that has passed through the pressure control valve 24 is vaporized, and methanol is aerosolized. The aerosolized methanol is easily evaporated. In this embodiment, a section of the piping that forms the fluid introduction flow path 32 is in contact with a cooling plate 36 that is temperature-controlled at a predetermined temperature (for example, 5 ° C.) by a Peltier element, and cools the fluid guided to the recovery container 34. Thus, evaporation of methanol is suppressed.

  The cooling means for cooling the fluid guided to the collection container 34 is not limited to this. FIG. 3 shows an embodiment in which the fluid flowing through the fluid introduction channel 32 is cooled using a low temperature thermostat. In the sample recovery mechanism 26B of this embodiment, one section of the piping forming the fluid introduction flow path 32 is a coiled portion 38, and the coiled portion 38 of each piping is accommodated in a common low temperature thermostat 40. Yes. The low temperature thermostat 40 is configured to maintain the internal space at a constant temperature (for example, 5 ° C.). As a result, the fluid passing through the coiled portion 38 is cooled, the evaporation of the methanol (modifier) in the fluid is prevented, and the methanol is guided to the recovery container 34 in a liquid state.

  A temperature sensor that detects the temperature of the fluid guided to the collection container 34 may be provided. By providing such a temperature sensor, it becomes easy to confirm whether or not the modifier is at a temperature that exists in a liquid state. Examples thereof are shown in FIGS.

  In the embodiment of FIG. 11, the piping of the drain 17 on the outlet side of the analysis channel 16 is also cooled by the cooling plate 36, and the temperature of the fluid flowing through the drain 17 is detected by the temperature sensor 64. . 12 and 13, the cooling mechanism 36a is provided on the upper side of the switching valve 30, and the temperature of the fluid that has passed through the cooling mechanism 36a is detected by the temperature sensor 64 on the upstream side of the switching valve 30 (the embodiment of FIG. 12). ) Or the temperature sensor 64 on the downstream side of the switching valve 30 (the embodiment shown in FIG. 13).

  A temperature sensor 64 that detects the temperature of the fluid that has passed through the cooling mechanism 36 is provided, and the output of the temperature sensor 64 is taken into the control unit 28 (see FIG. 1), so that the control unit 28 can be connected to the analysis channel 16. As a pre-stage for collecting the outflowing fluid in the collection container 34, it waits until the temperature of the fluid that has passed through the cooling mechanism 36 becomes equal to or lower than a predetermined temperature that is set as a temperature at which the modifier evaporation is suppressed. When it is detected by the temperature sensor 60 that the temperature of the fluid that has passed is below the predetermined temperature, the user can sort it by starting recovery to the recovery container 34 or lighting a predetermined lamp. It is possible to provide a function to notify that a new state has been reached.

  FIG. 4 shows an embodiment in which the cooling of the fluid led to the recovery container 34 is performed using cooling carbon dioxide.

  In the sample recovery mechanism 26 </ b> C of this embodiment, each section of the fluid introduction channel 32 is sandwiched between both aluminum blocks of a cooling block 56 configured by overlapping two aluminum blocks. A pipe 58 from a cylinder 54 for supplying carbon dioxide for cooling is connected to one end of the cooling block 56 by a fixing member made of, for example, a mail nut and ferrule. A pipe 60 for discharging carbon dioxide is connected to the other end of the cooling block 56 by a fixing member made of, for example, a mail nut and ferrule. Inside the cooling block 56, a flow path 62 is formed so as to guide the cooling carbon dioxide supplied through the pipe 58 to the pipe 60 on the other end side while spraying one section of all the fluid introduction flow paths 32. .

  The carbon dioxide enclosed in the cylinder 54 in a liquid state is reduced to atmospheric pressure and vaporized when passing through the pipe 58, supplied to the flow path 62 in a gas state, and discharged to the outside through the pipe 60. The cooling block 56 is cooled by the adiabatic expansion of carbon dioxide when carbon dioxide is supplied to the flow path 62, and the fluid temperature in one section of the fluid introduction flow path 32 sandwiched between the cooling blocks 56 is lowered. The evaporation of is suppressed.

  The cooling of the fluid guided to the recovery container 34 is not necessarily performed in the fluid introduction channel 32, but is performed in the analysis channel 16 between the pressure control valve 24 and the switching valve 30. It may be.

  Further, the cooling of the fluid guided to the recovery container 34 can be performed using an orifice in which the inner diameter of the flow path is partially narrowed. FIGS. 5, 6A and 6B show different examples of the structure of the fluid introduction flow path 32 having an orifice portion as a cooling means.

  In the example of FIG. 5, the fluid introduction flow path 32 is configured by an inlet pipe 32a and an outlet pipe 32b. The inlet pipe 32 a and the outlet pipe 32 b are connected by a joint 47. The downstream end of the inlet pipe 32a located on the upstream side is connected to the joint 47 by a fixing member 48a made of a mail nut and ferrule, and the upstream end of the outlet pipe 32b located on the downstream side is connected to the mail nut and ferrule. It is connected to the joint 47 by a fixing member 48b. In the joint 47, the downstream end of the inlet pipe 32a and the upstream end of the outlet pipe 32b are arranged to face each other. In the joint 47, the inner diameter of the portion 47a connecting the inlet pipe 32a and the outlet pipe 32b is smaller than the inner diameter of the inlet pipe 32a and the outlet pipe 32b. 46.

  In the example of FIG. 6A, the fluid introduction channel 32 is configured by direct connection of two pipes 32c and 32d. The upstream side pipe 32c is narrowed in the inner diameter and outer diameter at the downstream end by swaging, and the upstream end of the downstream side pipe 32d in which the narrowed downstream end portion has a larger inner diameter. Is inserted inside. The narrowed downstream end portion of the pipe 32 c forms the orifice portion 46.

  In the example of FIG. 6B, the fluid introduction flow path 32 is configured by a single pipe 32e, and the inner diameter in the middle of the pipe 32e is narrowed down by pressing. The narrowed portion of the pipe 32e forms an orifice portion 46.

  By providing the orifice part 46 as described above, the pressure between the pressure control valve 24 and the orifice part 46 is maintained at a somewhat high pressure, so that the carbon dioxide in the fluid that has passed through the pressure control valve 24 is reduced. It does not evaporate until it passes through the orifice 46. When the fluid passes through the orifice portion 46, the fluid temperature rapidly decreases due to the adiabatic expansion of carbon dioxide, and the evaporation of the modifier is suppressed. Thereby, the modifier in the fluid flowing out from the analysis flow path 16 is guided to the recovery container 34 in a liquid state, and is not discharged together with carbon dioxide from the upper surface opening of the recovery container.

  When a large amount of fluid passes through the orifice 46 having a small inner diameter, a large pressure loss occurs. Generally, the back pressure that can be controlled by the pressure control valve 24 is about 10 MPa to 40 MPa. Therefore, when the pressure loss in the orifice portion 46 is 10 MPa or more, the pressure control by the pressure control valve 24 becomes impossible. Therefore, it is desirable that the inner diameter of the orifice portion 46 is set so that the pressure loss generated in the orifice portion 46 is 8 MPa or less.

  Below, the result of having verified about the relationship between the temperature of the fluid which passed the pressure control valve 24, and the recovery rate is demonstrated.

  First, in order to confirm the influence of the temperature of the fluid on the recovery rate of the modifier (methanol), as shown in FIGS. 7A and 7B, a temperature adjustment unit 49 is provided on the rear side of the pressure control valve 24, and the temperature adjustment unit The recovery rate of methanol when the set temperature of 49 was changed from 20 ° C. to 60 ° C. was evaluated. The temperature adjusting unit 49 includes a heater for heating and a Peltier element for cooling, and these elements adjust the piping temperature on the outlet side of the pressure control valve 24 to a set temperature.

  In this experiment, an experiment was conducted in the case where the pipe 50 having the orifice portion 46 was connected to the downstream side of the temperature adjusting portion 49 (FIG. 7A) and the case where the pipe 52 having no orifice portion was connected. A pipe having an inner diameter of 1 mm and a length of 50 cm is arranged in the temperature adjustment section 49, and in the apparatus of FIG. 7A, the distance from the outlet of the temperature adjustment section 49 to the orifice section is 50 cm. The flow rate of methanol was 1 ml / min, the flow rate of carbon dioxide was 4 ml / min, and methanol flowing out from the outlet 50a (FIG. 7A) of the pipe 50 and the outlet 52a (FIG. 7B) of the pipe 52 was collected for 3 minutes.

  FIG. 8 shows a graph obtained by this experiment. When the orifice 46 is not provided (in the case of FIG. 7B), the methanol recovery rate was 63.3% when the set temperature of the temperature adjustment unit 49 was 20 ° C., but the methanol recovery was increased as the set temperature increased. The rate gradually decreased, and when the set temperature was 60 ° C., only a recovery rate of 10.0% was obtained. From these results, it was confirmed that the fluid temperature greatly affects the modifier recovery rate, and that the modifier recovery rate is improved by lowering the fluid temperature.

  On the other hand, when the orifice part 46 is provided, the recovery rate when the set temperature of the temperature control part 49 is 20 ° C. was 88.3%. As in the case where the orifice portion 46 is not provided, a tendency for the recovery rate to decrease as the set temperature of the temperature adjusting portion 49 is increased was confirmed. However, even when the set temperature is 60 ° C., the recovery rate is 83.3%. The rate was obtained. This is because the vaporization of the carbon dioxide that has passed through the orifice portion 46 reduces the fluid temperature and suppresses the evaporation of methanol, and a high recovery rate is obtained without the methanol being evaporated due to the temperature of the temperature adjusting portion 49. It is thought.

  Next, an experiment was conducted to verify the influence of the fluid temperature on the sample recovery rate using the apparatus shown in FIGS. 7A and 7B. The recovery rate of the sample when changing the set temperature of the temperature control unit 49 from 3 ° C. to 60 ° C. was evaluated. The flow rate of methanol is 1 ml / min, the flow rate of carbon dioxide is 4 ml / min, 20 μL of caffeine with a concentration of 2 mg / mL is injected as a sample, and the peak area of the detection signal of the UV detector 22 obtained at that time is measured. (This measured value is referred to as a first measured value.) Then, the solvent (methanol) containing caffeine was recovered from the fluid flowing out from the outlets 50a and 50b of the pipes 50 and 52 on the outlet side of the temperature control unit 49. Methanol was further added to the recovered solvent to adjust to 1 mL, and 20 μL of the adjusted solvent was again injected into the apparatus, and the peak area was measured (this measured value was the second measured value). That said.)

  In this experiment, if the ratio between the first measurement value and the second measurement value (second measurement value / first measurement value) is 1/50, a recovery rate of 100% is obtained. Since the measurement includes an error, it may exceed 100%. FIG. 9 shows the relationship between the set temperature of the temperature adjustment unit 49 and the sample recovery rate obtained by this experiment. When the orifice part 46 is not provided (in the case of FIG. 7B), the recovery rate when the set temperature of the temperature adjustment part 49 is 3 ° C. was 106.1%, but as the set temperature is increased, The recovery rate decreased, and when the set temperature was 60 ° C., only a recovery rate of 2.7% was obtained. Regarding the sample recovery rate, similarly to the methanol recovery rate, the recovery rate is high when the set temperature of the temperature control unit 49 is low, and the recovery rate is low when the set temperature of the temperature control unit 49 is high. Therefore, it is considered that when the fluid temperature becomes high and methanol evaporates, the sample is also lost.

  On the other hand, when the orifice part 46 is provided (in the case of FIG. 7A), the recovery rate is 107.7% when the set temperature of the temperature adjustment part 49 is 5 ° C., and the orifice part 46 is provided. As in the case where there is no temperature, the recovery rate of the sample tends to decrease as the set temperature of the temperature control unit 49 increases, but when the set temperature of the temperature control unit 49 is 60 ° C., a recovery rate of 89% is obtained. I was able to. From the above, in order to improve the recovery rate of the sample, it is effective to lower the temperature of the recovered fluid, and it is shown that providing the orifice part 46 is one of the means. .

  Further, when the flow rate of carbon dioxide is relatively large (for example, 10 ml / min to 150 ml / min), the fluid temperature is sufficiently lowered by the heat of vaporization of carbon dioxide, so that the cooling means 36 described in the above embodiment, Even if 40 and 46 are not used, it is considered that evaporation of methanol is suppressed and a high sample recovery rate can be obtained. Therefore, an experiment was conducted to evaluate the methanol recovery rate when the flow rate of carbon dioxide was changed without providing the cooling means as described above.

  In this experiment, an apparatus having the same configuration as in FIG. 7B is used, but since the flow rate of methanol is large, a tube having an inner diameter of 6 mm and a length of 15 cm is connected to the outlet of the pipe from which the fluid flows out, while preventing methanol from scattering. did. The recovery rate of methanol when the flow rate of carbon dioxide is 10 ml / min, 20 ml / min, 50 ml / min, 100 ml / min, 150 ml / min, and the temperature of the temperature adjusting unit 49 is set to 10 ° C. to 60 ° C. at each flow rate. Asked.

  The result of this experiment is shown in FIG. When the set temperature of the temperature control unit 49 was 10 ° C., 100% methanol recovery was obtained at all flow rates. Although the recovery rate decreases as the set temperature rises, it can be seen that when the flow rate is large, the rate of decrease in the recovery rate is small compared to when the flow rate is small, and the influence from the set temperature of the temperature controller 49 is small. It was. When the flow rate of carbon dioxide is large, the fluid is actively cooled by the heat of vaporization of carbon dioxide, so that the evaporation of methanol is sufficiently suppressed as in the case of using a cooling means, and the recovery rate is considered to be improved. . From the above results, when the flow rate of carbon dioxide is relatively large (for example, 10 ml / min to 150 ml / min), the fluid between the pressure control valve 24 and the collection container can be used without using a cooling means such as an orifice. Without heating, it was confirmed that the evaporation of the modifier can be suppressed by the heat of vaporization of carbon dioxide, and the recovery rate of the sample can be improved.

  As described above, the present invention is characterized in that the fluid that has passed through the pressure control valve is guided to the recovery container in a state in which the temperature is the temperature at which the modifier exists as a liquid. In order to recover the liquid in a liquid state, the fluid flowing out from the piping as disclosed in Patent Document 1 and Patent Document 2 is caused to flow down along the inner peripheral surface of the container, thereby utilizing centrifugal force. You may implement in combination with the method etc. which promote liquefaction of a modifier.

2 Carbon dioxide feed channel 4 Methanol feed channel 6,10 Pump 8 Carbon dioxide 12 Methanol 14 Mixer 16 Analysis channel 17 Drain 18 Sample injection part 20 Separation column 22 Detector 24 Pressure control valve 26A, 26B, 26C Sample Recovery mechanism 28 Control section 30 Switching valve 32, 50, 54 Fluid introduction flow path 32a, 32b, 32c, 32d, 32e Piping 34 Recovery container 36 Cooling means 38 Coiled portion 40 Low temperature thermostat 46 Orifice section 47 Joint 48a, 48b fixed Member 49 Temperature control part

Claims (10)

A sample recovery mechanism for recovering a liquid phase by separating a fluid flowing out from an analysis flow path of a supercritical fluid device into a gas phase and a liquid phase,
A collection container for collecting the fluid flowing out from the analysis flow path;
A fluid introduction part having a pipe connecting between the outlet of the analysis flow path and the recovery container, and introducing the modifier in the fluid introduced into the recovery container to a temperature at which the modifier exists as a liquid; A sample recovery mechanism.   The sample recovery mechanism according to claim 1, wherein the fluid introduction unit includes a cooling unit that cools the fluid upstream of the recovery container in the pipe.   The sample recovery mechanism according to claim 2, wherein the cooling means includes a Peltier element, and a portion cooled by the Peltier element comes into contact with a section of the pipe to cool the section.   The sample recovery mechanism according to claim 2, wherein the cooling means is a low-temperature thermostatic chamber that has a space for accommodating a section of the piping and maintains the inside of the space at a cooling temperature.   The sample recovery mechanism according to claim 2, wherein the cooling means sprays carbon dioxide for cooling on a section of the pipe.   The sample recovery mechanism according to claim 2, wherein the cooling means is an orifice portion in which the inner diameter of the pipe is narrowed to be smaller than the other part of the pipe. An analysis flow path in which a mixed fluid of carbon dioxide and a modifier flows as a mobile phase;
A sample introduction part for introducing a sample into the analysis flow path;
A separation column that is provided on the downstream side of the sample introduction part on the analysis flow path and separates the sample introduced from the sample introduction part for each component;
A detector that is provided further downstream of the separation column on the analysis flow path and detects a sample component separated by the separation column;
A pressure control valve that controls the pressure in the analysis flow path downstream of the detector of the analysis flow path to a pressure at which the mobile phase is in a supercritical state;
A supercritical fluid device comprising: the sample recovery mechanism according to any one of claims 1 to 6, which recovers a mobile phase that has passed through the pressure control valve. The sample recovery mechanism includes a plurality of recovery containers, and further includes a channel switching valve configured to selectively connect any one of the recovery containers to the outlet of the analysis channel. Prepared,
The flow path switching valve based on the detection signal of the detector so that the outlet of the analysis flow path is connected to a desired recovery container while the fluid containing the sample to be collected flows out of the analysis flow path. The supercritical fluid device according to claim 7, further comprising a control unit that controls the switching operation of. The flow rate of the carbon dioxide is 10 ml / min or more,
There is no heating mechanism for heating the fluid that has passed through the pressure control valve to a temperature higher than 10 ° C. between the pressure control valve and the sample recovery mechanism,
The supercritical fluid device according to claim 7 or 8, wherein the sample recovery mechanism does not include a cooling means for cooling the fluid.   The supercritical fluid device according to any one of claims 7 to 9, further comprising a temperature sensor that detects a temperature of a fluid guided to the recovery container by the sample recovery mechanism.

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