Sample concentration device

Abstract

A controller for controlling the operations of an autosampler, a sample push unit, and a make-up unit includes a pump stop timing setting unit for setting a first timing T1 of completion of dilution of a sample, and a subsequent second timing T2 of completion of trapping of a sample in the trap column, a dilution control unit for causing a solvent delivery pump for make-up of the make-up unit to operate, and for stopping operation of the solvent delivery pump for make-up at the first timing T1 set by the pump stop timing setting unit, and a sample push control unit for causing a solvent delivery pump for sample push of the sample push unit to operate, and for stopping operation of the solvent delivery pump for sample push at the second timing T2 set by the pump stop timing setting unit.

Claims

1. A sample concentration device comprising: an autosampler for injecting a certain volume of sample; a trap column configured to trap the sample so that the sample is concentrated; a sample push unit for delivering a sample injected by the autosampler to the trap column by a solvent delivery pump for sample push; a make-up unit configured to send a diluent by a solvent delivery pump so that the diluent is merged to a sample pushed out by the sample push unit at a merging point provided upstream of the trap column; and a controller configured to control operations of the autosampler, the sample push unit, and the make-up unit, wherein the controller comprises a pump stop timing setting unit for setting a first timing T1 of completion of dilution of a sample, and a subsequent second timing T2 of completion of trapping of a sample in the trap column, a dilution control unit for causing the solvent delivery pump for make-up of the make-up unit to operate, and for stopping operation of the solvent delivery pump for make-up at the first timing T1 set by the pump stop timing setting unit, and a sample push control unit for causing the solvent delivery pump for sample push of the sample push unit to operate, and for stopping operation of the solvent delivery pump for sample push at the second timing T2 set by the pump stop timing setting unit, wherein the pump stop timing setting unit sets a timing calculated based on a sample sweep volume as the second timing T2, and the sample sweep volume is the volume necessary for the end of a tailing portion of a sample bulk to pass from the merging point through the inside of the trap column and for the sample to be fixed to the trap column.

2. The sample concentration device according to claim 1, wherein the pump stop timing setting unit sets a timing calculated based on a sample injection volume as the timing T1.

3. The sample concentration device according to claim 2, wherein the controller is configured to swiftly stop a time program and end a concentration operation after stopping operation of the solvent delivery pump for sample push at the second timing T2.

4. The sample concentration device according to claim 1, wherein the pump stop timing setting unit stores in advance a timing T1 calculated based on a maximum sample injection volume and a timing T2 calculated based on the sample sweep volume, and when notified of a sample injection volume by the autosampler, calculates a timing T1 based on the notified sample injection volume and takes the timing T1 as a set value of the timing T1, and when not notified of a sample injection volume by the autosampler, takes the timing T1 stored in advance as a set value.

5. The sample concentration device according to claim 4, wherein the controller is configured to swiftly stop a time program and end a concentration operation after stopping operation of the solvent delivery pump for sample push at the second timing T2.

6. The sample concentration device according to claim 1, comprising a probe for detecting a sample bulk end at a stage preceding the trap column, wherein the pump stop timing setting unit sets a timing calculated based on a timing of a detection signal of the probe as the timing T1.

7. The sample concentration device according to claim 6, wherein the controller is configured to swiftly stop a time program and end a concentration operation after stopping operation of the solvent delivery pump for sample push at the second timing T2.

8. The sample concentration device according to claim 1, wherein the controller is configured to swiftly stop a time program and end a concentration operation after stopping operation of the solvent delivery pump for sample push at the second timing T2.

Description

BRIEF DESCRIPTION OF DRAWING

(1) FIG. 1 is a schematic flow path diagram showing a first embodiment in a flow path state at the time of idling or a flow path state at the time of injection/sample trapping.

(2) FIG. 2 is a block diagram for describing functions of a controller of a sample concentration device of the present invention.

(3) FIG. 3 is a waveform diagram showing example fractionation of two component peaks by a preparative system for obtaining a sample for the sample concentration device.

(4) FIG. 4 is a schematic flow path diagram showing the present embodiment in a flow path state at the time of sample metering.

(5) FIG. 5 is a time chart showing an operation of the present embodiment.

(6) FIG. 6 is a schematic flow path diagram showing a second embodiment.

(7) FIG. 7 is a time chart showing an operation of the present embodiment.

MODE FOR CARRYING OUT THE INVENTION

Embodiment 1

(8) FIGS. 1 and 4 schematically show a sample concentration device of a first embodiment. The sample concentration device is a device for injecting a sample, and trapping (collecting) the sample in a trap column, and includes an autosampler 1 for injecting a certain volume of sample, a trap column 8, a sample push unit 5 for delivering a sample injected by the autosampler 1 to the trap column 8 by a solvent delivery pump 5a or 5b for sample push, a make-up unit 6 for compensating for a diluent by a solvent delivery pump 6a or 6b for make-up with respect to a sample pushed out by the sample push unit 5, and a controller 15 for controlling operations of the autosampler 1, the sample push unit 5, and the make-up unit 6.

(9) The sample concentration device is sometimes incorporated in a liquid chromatograph as a part of the liquid chromatograph. In such a case, the trap column 8 is separated from a concentration device and is connected to an analysis system by a flow path switching valve, and a sample trapped in the trap column 8 is eluted by a solvent delivery pump for elution, and is analyzed in the column. The sample concentration device of the present invention also includes such a mode, but in the embodiments, description of parts other than the concentration device is omitted.

(10) At the autosampler 1, a sample loop 4 is connected between two ports of a high-pressure valve 2, and a sampling needle 30 is connected to another port of the high-pressure valve 2, and a syringe pump 3, which is a metering pump, is connected to further another port of the high-pressure valve 2. The sample push unit 5 is connected to further another port of the high-pressure valve 2, and the trap column 8 is connected to further another port of the high-pressure valve 2.

(11) At the autosampler 1, a sample in a sample vial 32 is drawn by the syringe pump 3 from the sampling needle 30 into the sample loop 4 (FIG. 4), and the high-pressure valve 2 is switched, and thus, the sample drawn into the sample loop 4 is delivered to the trap column 8 by a solvent from the sample push unit 5 (FIG. 1).

(12) At the autosampler 1, a drain valve 13 is connected between the syringe pump 3 and the high-pressure valve 2. After an injection process, a mobile phase that is drawn into a metering flow path of the syringe pump 3 from the sample loop 4 at the time of drawing of the sample is discharged from the drain valve 13.

(13) At the autosampler 1, a rinsing port 34 for rinsing the sampling needle 30 is arranged, and a rinsing liquid 36 is connected to the syringe pump 3 via a switching valve 35. At the time of rinsing of the sampling needle 30 and the flow path from the high-pressure valve 2 to the sampling needle 30 in the injection state in FIG. 1, rinsing is performed by inserting the sampling needle 30 into the rinsing port 34 and drawing the rinsing liquid into the syringe pump 3 via the switching valve 35, and then, switching the switching valve 35, and discharging the rinsing liquid which was drawn into the syringe pump 3 from the sampling needle 30.

(14) The flow path structure (the connection method of the high-pressure valve 2, the sample loop 4, and the sampling needle 30) of the autosampler 1 may take another structure. For example, a structure is possible where the syringe pump 3 on a separate flow path is directly connected to the sampling needle 30, an injection port is connected to another port of the high-pressure valve 2, and a sample is pushed into the sample loop 4. Also, for example, a structure is possible where the sample loop 4 is connected to one port of the high-pressure valve 2 and the sampling needle 30 is directly connected at its tip end, where the syringe pump 3 on a separate flow path is connected to the sampling needle 30, and where an injection port is connected to another port of the high-pressure valve 2, and after a sample is drawn into the sample loop 4 from the sampling needle 30 by the syringe pump 3, the sampling needle 30 is inserted into the injection port and the total volume of the sample in the sample loop 4 is injected into the flow path (total volume injection method).

(15) Two solvent delivery pumps 5a and 5b for sample push are provided to the sample push unit 5, and since these solvent delivery pumps 5a and 5b are connected to the high-pressure valve 2 in parallel, one of two types of solvents or a mixture thereof may be supplied. However, the sample push unit 5 may alternatively be provided with only one solvent delivery pump.

(16) Four types of solvents may be drawn into each of the solvent delivery pumps 5a and 5b, but the number of solvents is not limited thereto, and any number of types may be used including one type.

(17) A three-way joint 7 is provided on the flow path through which a sample is transferred from the high-pressure valve 2 to the trap column 8, and the make-up unit 6 is connected via the three-way joint 7. The make-up unit 6 is for compensating for a diluent to dilute a sample.

(18) Two solvent delivery pumps 6a and 6b are also provided to the make-up unit 6, and since these solvent delivery pumps 6a and 6b are connected to the high-pressure valve 2 in parallel, one of two types of solvents or a mixture thereof may be supplied as a diluent. However, the make-up unit 6 may alternatively be provided with only one solvent delivery pump. Four types of solvents may be drawn into each of the solvent delivery pumps 6a and 6b, but the number of solvents is not limited thereto, and any number of types may be used including one type.

(19) The controller 15 may be realized by a dedicated computer of the concentration device or of a liquid chromatograph in which the concentration device is installed, or may be realized by a general-purpose personal computer. Moreover, it may be realized by both the dedicated computer and the personal computer.

(20) The autosampler 1, the sample push unit 5, the make-up unit 6, and the controller 15 may be integrated, or they may be separate units.

(21) The functions of the controller 15 are the structures shown in FIG. 2. A pump stop timing setting unit 20 sets a first timing T1 of completion of dilution of a sample, and a subsequent second timing T2 of completion of trapping of a sample in the trap column 8. A dilution control unit 22 causes the solvent delivery pumps 6a and 6b of the make-up unit 6 to operate, and stops the operations of the solvent delivery pumps 6a and 6b at the first timing T1 set by the pump stop timing setting unit 20. A sample push control unit 24 causes the solvent delivery pumps 5a and 5b of the sample push unit 5 to operate, and stops the operations of the solvent delivery pumps 5a and 5b at the second timing T2 set by the pump stop timing setting unit 20.

(22) In this embodiment, the pump stop timing setting unit 20 sets the timing T1 based on the sample injection volume. Specific description will be given later, but as an example, the pump stop timing setting unit 20 stores in advance a timing T1 calculated based on the maximum sample injection volume, and when notified of a sample injection volume by the autosampler 1, calculates a timing T1 based on the notified sample injection volume and takes the timing T1 as the set value of the timing T1, and when not notified of a sample injection volume by the autosampler 1, takes the timing T1 stored in advance as the set value.

(23) FIG. 1 shows the state of the high-pressure valve 2 at the time of idling and at the time of sample trapping. At the time of sample metering, the high-pressure valve 2 is rotated to be in the state in FIG. 4.

(24) A control method according to the present embodiment for performing sample concentration will be described with reference to the time chart in FIG. 5.

(25) First, an instrument method for controlling the sample concentration device is downloaded from the controller 15 to the autosampler 1, the sample push unit 5, the make-up unit 6, and other necessary units (Download method).

(26) The instrument method includes, in addition to parameters for controlling the autosampler 1, the sample push unit 5, and the make-up unit 6, a time program, a pre-treatment program, and the like.

(27) The time program and the pre-treatment program may be executed by the controller 15, or by each of the autosampler 1, the sample push unit 5, and the make-up unit 6.

(28) One of the parameters for controlling the sample push unit 5 and the make-up unit 6 is the dilution rate. The dilution rate is normally determined based on the flow rate ratio of the sample push unit 5 and the make-up unit 6.

(29) As other parameters for controlling the sample push unit 5 and the make-up unit 6, there are the first timing T1 and the second timing T2 that are set by the pump stop timing setting unit 20. The first timing T1 is the timing of stopping the operations of the solvent delivery pumps 6a and 6b for make-up. To determine this first timing T1 according to the sample injection volume, the sample injection volume is multiplied by, for example, a factor such as the tailing factor of a sample bulk.

(30) The second timing T2 is the timing of stopping the operations of the solvent delivery pumps 5a and 5b for sample push. To determine this second timing T2, for example, a sample sweep volume (the volume necessary for fixation of a sample) that is dependent mainly on the volume of the trap column 8 is taken into account.

(31) The pre-treatment program is a program including sequential executable commands included in the instrument method, and includes as necessary, in addition to operations such as addition/mixing of an additive or dilution at the sample vial 32, discharging of a mobile phase in the metering flow path of the syringe pump 3 after injection, and rinsing of the sampling needle 30 and the flow path from the high-pressure valve 2 to the sampling needle 30, an operation of rewriting the sample position for drawing a sample at the autosampler 1 and the volume to be drawn that are normally specified in a batch table.

(32) The time program is a program for determining the timings (analysis elapsed time of command execution) of controlling the operations of the autosampler 1, the sample push unit 5, the make-up unit 6, and other necessary units after output of a start signal (after an analysis is started), and includes the timings of controlling the operations of the sample push unit 5 and the make-up unit 6 using parameters T1 and T2.

(33) Next, the controller 15 downloads, to the autosampler 1, sample information such as the position of the vial (sample vial) of a sample, the injection volume, and the like (Download sample information).

(34) Then, the controller 15 instructs the autosampler 1 to start the pre-treatment program (Run pre-treatment program).

(35) According to the contents of the pre-treatment program, the autosampler 1 switches the high-pressure valve 2 to the sample metering position (the state in FIG. 4), and starts a sample drawing operation.

(36) After the sample drawing operation, the autosampler 1 transmits to the controller 15, according to the contents of the pre-treatment program, an event signal for starting the time program (Event signal), and the controller 15 starts the time program (Run time program). The event signal may be a digital signal generated by software, or may be an analog signal such as a relay signal.

(37) The controller 15 receives the event signal, and causes the sample push unit 5, the make-up unit 6, and other necessary units to perform an analysis operation including execution of the time program (Start pumps).

(38) This is taken as the start time of the time program.

(39) According to the contents of the pre-treatment program, at the time of switching the high-pressure valve 2 to the injection position (the state in FIG. 1), the autosampler 1 notifies the controller 15 of an injection start signal and the sample injection volume (Injection Signal/Injection Volume). This is taken as a timing T0.

(40) The controller 15 calculates the parameter T1 for stopping the make-up unit 6 with respect to the injection volume which has been notified.

(41) The parameters T1 and T2 to be calculated are, for example, as follows.

(42) The injection start notification time is taken as T0. The elapsed time

(43) (T0+T1) of the time program for stopping the solvent delivery pump of the make-up unit 6 is
(T0+T1)=T0+V+?Ft/M(1),
where

(44) V: sample injection volume which has been notified,

(45) Ft: tailing factor,

(46) M: flow rate of sample push unit 5.

(47) The elapsed time (T0+T1+T2) of the time program for stopping the solvent delivery pump of the sample push unit 5 is
(T0+T1+T2)=T0+T1+Vs/M(2),
where

(48) Vs: sample sweep volume.

(49) Then, according to the calculated parameters T1 and T2, the controller 15 stops the make-up unit 6 when, after injection, dilution becomes unnecessary, and then, stops the sample push unit 5 after the sample is fixed to the trap column 8.

(50) As an example, the make-up unit 6 is stopped after the lapse of time T0 (the time of sample injection) from the output of an event signal (start of the time program) and also after the lapse of time T1, and then the sample push unit 5 is stopped after the lapse of time T2.

(51) In the embodiment, T1 that is calculated by using the maximum sample injection volume and T2 that is calculated by using the sample sweep volume are stored, and the time program is created based on the T1 and T2 that are stored. In the case where a sample injection volume is notified by the autosampler 1, and the value is not zero, operation is performed based on the T1 that is calculated by using the notified sample injection volume and the T2 that is calculated by using the sample sweep volume. In the case where the sample injection volume is not notified, or the value of the notified sample injection volume is zero, operation is performed based on the T1 that is calculated by using the maximum sample injection volume and the T2 that is calculated by using the sample sweep volume. This is because there may be an analysis operation where the autosampler 1 does not operate.

(52) Additionally, the injection volume to be notified by the autosampler 1 may be the sample volume input by the controller 15, or in the case where addition/mixing of an additive or dilution is performed by the pre-treatment program, this may be taken into account with respect to the volume.

(53) Furthermore, the controller 15 may use, as the sample volume, the sample volume input to the controller 15 as it is, instead of the injection volume notified by the autosampler 1, or may use an injection volume calculated based on the contents of the pre-treatment program or the parameters of the instrument method.

(54) Additionally, the sample concentration device of this embodiment assumes delivery of a large volume, and thus is an embodiment according to which the time program is started in the pre-treatment program to start delivery by the solvent delivery pump, and then a sample is injected after the delivery becomes stable, but it is needless to say that sample injection may be swiftly performed by starting delivery during idling, before the pre-treatment program is started, starting the time program, in the pre-treatment program, at the same time as injection is enabled, and starting delivery by the solvent delivery pumps of the sample push unit 5 and the make-up unit 6.

Embodiment 2

(55) FIG. 6 schematically shows a sample concentration device of a second embodiment.

(56) One aspect that is different from the first embodiment is that a sample end detection probe 16 is provided at a stage preceding the trap column 8, and the end of a sample that is introduced into the trap column 8 is detected. Another difference is that, since the sample end detection probe 16 is provided, the pump stop timing setting unit 20 at the controller 15 shown in FIG. 2 is configured to set the timing T1 based on the timing of the detection signal of the probe 16. Other aspects such as the flow path structure are the same as in the first embodiment, and detailed description of the same parts will be omitted.

(57) The sample end detection probe 16, for example, detects a change in the physical property between a mobile phase and a sample solvent. As the physical property, an optical property such as a refractive index may be cited, and the sample end detection probe 16 in this case optically detects a change in such an optical property.

(58) The controller 15 detects the end of a sample bulk by taking the output of the sample end detection probe 16 as an input.

(59) As a parameter for controlling the make-up unit 6 according to sample end detection by the sample end detection probe 16, for example, a delay time from passing of the end of a sample bulk to passing of a tailing portion, a parameter for tuning the detection sensitivity for a change in the physical property between a mobile phase baseline and a sample solvent, and the like may be cited.

(60) A control method according to the present embodiment for performing sample concentration will be described with reference to the time chart in FIG. 7. The difference to the sample concentration control method according to the first embodiment is that, in the present embodiment, control is performed based on a sample end detection event by the sample end detection probe 16 instead of the injection timing of the autosampler 1.

(61) The controller 15 calculates the parameters for stopping the sample push unit 5 and the make-up unit 6 in response to a sample end detection event (Event signal) from the sample end detection probe 16.

(62) The parameters to be calculated are, for example, as follows.

(63) The sample end detection time is taken as T0. Time 0 indicates the start of the time program. Time (T0+T1) for stopping the solvent delivery pump of the make-up unit 6 is
(T0+T1)=T0+delay time(3).

(64) The delay time is a temporal margin for guaranteeing passing of the end of a sample bulk to passing of the tailing portion.

(65) The time (T0+T1+T2) for stopping the solvent delivery pump of the sample push unit 5 is
(T0+T1+T2)=T0+T1+Vs/M(2a),
and is, in form, the same as Equation (2). Here, as defined above, Vs is the sample sweep volume, and M is the flow rate of the sample push unit 5.

(66) It is also possible to use, as the sample end detection probe 16, or as an alternative device of the sample end detection probe 16, an optical detector such as an UV (ultraviolet) detector.

(67) Also in this embodiment, the controller 15 may be realized by a dedicated computer of the concentration device or of a liquid chromatograph in which the concentration device is installed, or may be realized by a general-purpose personal computer. Moreover, it may be realized by both the dedicated computer and the personal computer.

(68) The autosampler 1, the sample push unit 5, the make-up unit 6, the controller 15, and the sample end detection probe 16 may be integrated, or they may be separate units.

Embodiment 3

(69) Normally, the analysis time is a fixed time that is specified as a part of the analysis conditions, or that is specified as the end time of the time program. The analysis time includes a sample concentration time.

(70) When it is not notified of a sample injection volume or a notified sample injection volume is zero, a sample concentration device of the third embodiment is terminated at the end time of the time program set in advance, and when it is notified of a sample injection volume, it is normally terminated at the same time as the sample push unit 5 is stopped. To this end, the controller 15 swiftly stops the time program and ends the concentration operation after stopping the operation of the solvent delivery pumps 5a and 5b for sample push at the second timing T2.

EXPLANATION OF REFERENCE LETTERS

(71) 1: Autosampler 2: High-pressure valve 3: Syringe pump 4: Sample loop 5: Sample push unit 6: Make-up unit 7: Three-way joint 8: Trap column 9: Fraction component for vial #1 (only component A) 10: Fraction component for vial #2 (only component A) 11: Fraction component for vial #3 (components A and B) 12: Fraction component for vial #4 (only component A) 13: Drain valve 15: Controller 16: Sample detection end probe 20: Pump stop timing setting unit 22: Dilution control unit 24: Sample push control unit 34: Rinsing port 35: Switching valve 36: Rinsing liquid