Liquid chromatography tail liquid collecting device

Abstract

The invention relates to a liquid chromatogram tail liquid collecting device, which can accurately collect each chromatographic peak in HPLC (High Performance Liquid Chromatography) analysis by setting delay dead time, and has the advantages of small diffusion, small volume, low cost and the like.

Description

Technical Field

[0001] The invention relates to a tail liquid collecting device, belonging to the fields of medicine, food and chemistry, and in particular to a tail liquid collecting device for liquid chromatography. Background Art

[0002] Liquid chromatography is a type of separation and analysis technology, which is characterized by using liquid as the mobile phase. The high performance liquid chromatography (HPLC) system is mainly composed of a mobile phase storage bottle, an infusion pump, an injector, a chromatographic column, a detector and a recorder. High performance liquid chromatography is widely used in almost all fields of quantitative and qualitative analysis. Liquid chromatography can effectively separate the target main component from various impurity components, and quantify each component by integrating the detector signal.

[0003] In drug research, it is often necessary to obtain impurities with very low content in HPLC analysis for structural identification research. This usually requires the use of a dedicated preparative liquid chromatograph and a preparative column for preparation, but preparative liquid chromatography is expensive, and the consumable preparative chromatographic column is much more expensive than a conventional chromatographic column. In addition, due to the obvious differences in system dead volume and retention behavior of the preparative column, the HPLC conditions used in preparative liquid chromatography are usually not the same as those used in conventional analysis. This results in the peak positioning of preparative HPLC not necessarily being comparable to that of conventional analytical HPLC, which creates great difficulties in tracking and preparing impurities in conventional analytical HPLC.

[0004] Patent application No. 202021056964.5 provides a static injection and fraction collection device for use with a liquid chromatograph, wherein the fraction collection device is directly connected to a multi-channel switching valve at the detector outlet. The switching of the multi-channel switching valve usually takes several seconds, while the flow of the mobile phase is always ongoing. When the switching valve is located between two adjacent channels, the flow of the mobile phase has no outlet, which causes the pressure in the system to increase rapidly and then decrease during the switching of the multi-channel switching valve. This drastic change in pressure greatly increases the diffusion of the target fraction, making it difficult to collect pure target components, and in the process of switching to the target channel, the switching valve will inevitably pass through other channels and form passages with other channels, causing contamination to other channels. In addition, its cleaning pipeline requires cooperation with the liquid chromatograph end, and cannot be cleaned independently of the liquid chromatograph. When the system needs to be emptied, the connection with the detector can only be manually removed and the system can only be manually emptied. Summary of the invention

[0005] In view of the above-mentioned defects of the existing processing methods, the purpose of the present invention is to provide a liquid chromatography tail liquid collection device, which is connected to the tail of a conventional HPLC in the form of a small box. The diffusion is small during the collection process, and no cross contamination will occur during the switching process of the switching valve. It also has an online purge function, which can purge and collect the liquid in each branch pipe after the switching valve, which is conducive to collecting the precious impurity samples that are already few. There is no need to disconnect the connection with the HPLC during purging, cleaning and emptying, and it has no effect on the normal operation of the HPLC. In conventional HPLC analysis, effective separation of each impurity and the main component can be achieved, and the desired target impurity can be prepared during conventional analysis without the need for preparation of HPLC, and the separated target impurity is the impurity at the specified retention time in the conventional HPLC analysis, which greatly simplifies the impurity tracking and preparation in conventional HPLC analysis. This device can also realize the classified collection of chromatographic methanol, chromatographic acetonitrile and other chromatographic reagents, greatly reducing the difficulty of recycling and processing chromatographic pure reagents.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A tail liquid collection device comprises a first three-way solenoid valve (1), a second three-way solenoid valve (2), a third three-way solenoid valve (3), a multi-channel switching valve (4), a fourth three-way solenoid valve (5), a peristaltic pump (6), a one-way valve (7), a T-shaped three-way valve (8) and a controller (9), wherein the first three-way solenoid valve (1) is connected to a liquid chromatography detector (15), the second three-way solenoid valve (2) and the one-way valve (7), the second three-way solenoid valve (2) is connected to the first three-way solenoid valve (1), the peristaltic pump (6) and the third three-way solenoid valve (3), the third three-way solenoid valve (3) is connected to the second three-way solenoid valve (2), the multi-channel switching valve (4) and the T-shaped three-way valve (8), and the multi-channel switching valve (4) is located at the third three-way solenoid valve (3). Afterwards, switching is performed between the multiple channels to collect the flow fractions. The fourth three-way solenoid valve (5) is connected to the peristaltic pump (6), the cleaning liquid interface and the air interface to switch to the cleaning liquid or air. The peristaltic pump (6) is connected to the fourth three-way solenoid valve (5) and the second three-way solenoid valve (2) to extract the cleaning liquid or air to purge, clean or empty the pipeline. The one-way valve (7) is connected to the first three-way solenoid valve (1) and the T-shaped three-way valve (8) to prevent the liquid flow or air flow generated by the peristaltic pump from affecting the liquid chromatography. The T-shaped three-way valve (8) is connected to the one-way valve (7), the third three-way solenoid valve (3) and the waste liquid. The controller (9) performs the operations of cleaning the pipeline before cleaning, cleaning the channel, emptying the pipeline before emptying, emptying the channel, collecting and purging according to the user-set program.

[0007] Preferably, the first three-way solenoid valve (1) and the second three-way solenoid valve (2) are connected to the same solenoid valve drive interface, and a high-low level signal of the controller (9) is used to realize simultaneous switching of situation one (the first three-way solenoid valve (1) is connected to the one-way valve (7), and the second three-way solenoid valve (2) is connected to the peristaltic pump (6)) and situation two (the first three-way solenoid valve (1) is connected to the second three-way solenoid valve (2), and the second three-way solenoid valve (2) is connected to the first three-way solenoid valve (1)), thereby improving the simultaneity of valve switching and further reducing the influence of the start of the peristaltic pump on the liquid chromatography.

[0008] Preferably, the tail liquid collection device further comprises an air filter (14), wherein the air filter (14) is located before the air interface of the fourth three-way solenoid valve (5) and filters the inhaled air to prevent dust particles from entering the system.

[0009] Preferably, the tail liquid collection device further comprises a detector, which is located after the multi-channel switching valve (4) and performs online monitoring of the collected fractions to verify the correctness of the collection.

[0010] Preferably, the tail liquid collector further comprises an organic solvent sensor, which monitors the concentration of organic solvent volatilized in the air and gives an alarm when the tail liquid is fully collected and overflows.

[0011] Preferably, the present invention can accurately collect each chromatographic peak in the liquid chromatography by measuring the inherent delayed dead time from the liquid chromatography detector (15) to the outlet of the multi-channel switching valve (4) or calculating the delayed dead time based on the inherent dead volume and flow rate.

[0012] Preferably, the delayed dead time determination method is as follows: the emptied device is connected to the rear end of a liquid chromatography detector (15), the first three-way solenoid valve (1) is connected to the second three-way solenoid valve (2), the second three-way solenoid valve (2) is connected to the third three-way solenoid valve (3), the third three-way solenoid valve (3) is connected to the multi-channel switching valve (4), the liquid chromatography pump is turned on at a flow rate set by the method, and timing (T1) is started at the same time, and the timing is stopped when the liquid flows out of the outlet of the multi-channel switching valve (T2), and the time difference between the two is the delayed dead time (T2-T1).

[0013] Preferably, the dead volume determination method is as follows: the device is completely emptied, a liquid pump is connected before the first three-way solenoid valve (1), the weight of water (W1) before the liquid pump is turned on is recorded, the first three-way solenoid valve (1) is connected to the second three-way solenoid valve (2), the second three-way solenoid valve (2) is connected to the third three-way solenoid valve (3), the third three-way solenoid valve (3) is connected to the multi-channel switching valve (4), the liquid pump is turned on, when liquid flows out from the outlet of the multi-channel switching valve (the outflow liquid returns to the source liquid), a delay of 10 seconds is made to allow complete filling, the weight of the outflow liquid (W2) and the remaining water (W3) is recorded, and the previous weight minus the remaining weight divided by the density of water 1.0 is the dead volume of the device ((W1-W2-W3) / 1.0). Beneficial Effects

[0014] (1) The diffusion of the present invention is small, the pressure is stable during operation, and there is no effect on HPLC.

[0015] (2) The present invention can perform purging, emptying and cleaning online without affecting the normal operation of HPLC.

[0016] (3) The present invention can be attached to the tail of HPLC during routine HPLC analysis (such as quality research or stability research) to separate and purify the main components and impurities.

[0017] (4) The present invention can realize the classified collection of methanol, acetonitrile and other chromatographic reagents, greatly reducing the difficulty of recovery.

[0018] (5) The present invention can achieve the removal of the main component for isocratic HPLC analysis (such as content determination), and the remaining mobile phase can still be reused.

[0019] (6) The present invention can purge the liquid in the pipeline after the multi-channel switching valve, making it convenient to collect samples.

[0020] (7) The present invention can conveniently and effectively clean and empty the pipelines in the entire device system, and even blow them dry when necessary, so as to prepare for the next separation and purification.

[0021] (8) The device of the present invention has low cost, occupies very little space, and is easy to move. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the tail liquid collection device embodiment 1 of the present invention. In the figure: 1. three-way solenoid valve, 2. second three-way solenoid valve, 3. third three-way solenoid valve, 4. multi-channel switching valve, 5. fourth three-way solenoid valve, 6. peristaltic pump, 7. one-way valve, 8. T-type three-way valve, 9. controller, 10. fraction collection bottle, 11. air, 12. cleaning solution, 13. waste liquid collection bottle, 14. air filter, 15. liquid chromatography detector.

[0023] Figure 2 Schematic diagram of the chromatographic peak of the tail liquid collection device of the present invention in Example 1 In the figure: the target chromatographic peaks to be collected are in the box, and the number of each chromatographic peak and the corresponding target retention time are marked on the box in the form of "chromatographic peak number: starting retention time-ending retention time". Implementation

[0024] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Example

[0025] like Figure 1 As shown, a tail liquid collection device includes a first three-way solenoid valve, a second three-way solenoid valve, a third three-way solenoid valve, a multi-channel switching valve, a fourth three-way solenoid valve, a peristaltic pump, a one-way valve, a T-type three-way valve, an air filter, and a controller.

[0026] The working procedure of the tail liquid collection device is as follows: Clean the front-end pipeline: connect the fourth three-way solenoid valve (5) to the cleaning liquid (12), connect the second three-way solenoid valve (2) to the peristaltic pump (6), connect the third three-way solenoid valve (3) to the T-type three-way valve (8), turn on the peristaltic pump (6), pump in the cleaning liquid to clean the pipeline, and stop the peristaltic pump (6).

[0027] Cleaning each channel: the multi-channel switching valve (4) is switched to the channel to be cleaned, the fourth three-way solenoid valve (5) is connected to the cleaning liquid (12), the second three-way solenoid valve (2) is connected to the peristaltic pump (6), the third three-way solenoid valve (3) is connected to the multi-channel switching valve (4), the peristaltic pump (6) is turned on, the cleaning liquid is pumped into the channel, and the peristaltic pump (6) is stopped. In this way, each channel is cleaned.

[0028] Empty the front-end pipeline: connect the fourth three-way solenoid valve (5) to the air filter (14), connect the second three-way solenoid valve (2) to the peristaltic pump (6), connect the third three-way solenoid valve (3) to the T-type three-way valve (8), open the peristaltic pump (6), pump air into the pipeline, and stop the peristaltic pump (6).

[0029] Empty each channel: the multi-channel switching valve (4) is switched to the channel to be cleaned, the fourth three-way solenoid valve (5) is connected to the air filter (14), the second three-way solenoid valve (2) is connected to the peristaltic pump (6), the third three-way solenoid valve (3) is connected to the multi-channel switching valve (4), the peristaltic pump (6) is turned on, air is pumped into the channel, and the peristaltic pump (6) is stopped. In this way, each channel is emptied.

[0030] Tail liquid collection: The user sets the retention time of each peak in the liquid chromatography and the corresponding target channel, such as Figure 2 As shown, the settings are as follows: Under normal conditions, the first three-way solenoid valve (1) is connected to the second three-way solenoid valve (2), and the second three-way solenoid valve (2) is connected to the third three-way solenoid valve (3). After the sample is injected into the liquid chromatograph, the external interrupt of the controller (9) is triggered, and the controller (9) starts to execute timing. When the delayed dead time + peak start time (for example, for peak 1, it is 3.2 + 3.7 = 6.9 minutes after the trigger timing) is reached, the third three-way solenoid valve (3) is connected to the T-type three-way valve (8), and the multi-channel switching valve (4) is switched to the target channel 1. When the multi-channel switching valve (4) is switched, the third three-way solenoid valve (3) is connected to the multi-channel switching valve (4) to perform fraction collection. When the delayed dead time + peak end time (for example, for peak 1, it is 3.2 + 4.4 = 7.6 minutes after the trigger timing) is reached, the third three-way solenoid valve (3) is connected to the T-type three-way valve (8), and the multi-channel switching valve is switched to other channels 6 (to collect other fractions). In this way, accurate collection of each chromatographic peak is achieved.

[0031] Purge: After the execution sequence collection is completed, the first three-way solenoid valve (1) is connected to the one-way valve (7), and then the front pipeline is emptied according to the aforementioned method of "emptying the front pipeline". After the emptying is completed, the multi-channel switching valve (4) is switched to the channel that needs to be purged, the fourth three-way solenoid valve (5) is connected to the air filter (14), the second three-way solenoid valve (2) is connected to the peristaltic pump (6), and the third three-way solenoid valve (3) is connected to the multi-channel switching valve (4). The peristaltic pump (6) is turned on to pump air into the channel to purge it, and the peristaltic pump (6) is stopped. In this way, each channel is purged.

[0032] The collected fractions were analyzed using the same chromatograph and the same chromatographic method. The results showed that the collected fractions of the present invention were target fractions, and the chromatographic peaks of the collected fractions corresponded one to one with the chromatographic peaks of the original sample.

Claims

1. A liquid chromatography tail liquid collection device, comprising a first three-way solenoid valve (1), a second three-way solenoid valve (2), a third three-way solenoid valve (3), a multi-channel switching valve (4), a fourth three-way solenoid valve (5), a peristaltic pump (6), a one-way valve (7), a T-shaped three-way valve (8) and a controller (9), wherein the first three-way solenoid valve (1) is connected to a liquid chromatography detector (15), the second three-way solenoid valve (2) and the one-way valve (7), the second three-way solenoid valve (2) is connected to the first three-way solenoid valve (1), the peristaltic pump (6) and the third three-way solenoid valve (3), the third three-way solenoid valve (3) is connected to the second three-way solenoid valve (2), the multi-channel switching valve (4) and the T-shaped three-way valve (8), and the multi-channel switching valve (4) is located at the third three-way solenoid valve (3) Afterwards, switching is performed between the multiple channels to collect the flow fractions. The fourth three-way solenoid valve (5) is connected to the peristaltic pump (6), the cleaning liquid interface and the air interface to switch to the cleaning liquid or air. The peristaltic pump (6) is connected to the fourth three-way solenoid valve (5) and the second three-way solenoid valve (2) to extract the cleaning liquid or air to purge, clean or empty the pipeline. The one-way valve (7) is connected to the first three-way solenoid valve (1) and the T-type three-way valve (8) to prevent the liquid flow or air flow generated by the peristaltic pump from affecting the liquid chromatography. The T-type three-way valve (8) is connected to the one-way valve (7), the third three-way solenoid valve (3) and the waste liquid. The controller (9) performs the operations of cleaning the pipeline before cleaning, cleaning the channel, emptying the pipeline before emptying, emptying the channel, collecting and purging according to the user-set program.

2. A liquid chromatography tail liquid collecting device according to claim 1, characterized in that: The first three-way solenoid valve (1) and the second three-way solenoid valve (2) are connected to the same solenoid valve drive interface, and a high-low level signal of the controller (9) is used to realize simultaneous switching between situation one (the first three-way solenoid valve (1) is connected to the one-way valve (7), and the second three-way solenoid valve (2) is connected to the peristaltic pump (6)) and situation two (the first three-way solenoid valve (1) is connected to the second three-way solenoid valve (2), and the second three-way solenoid valve (2) is connected to the first three-way solenoid valve (1)).

3. A liquid chromatography tail liquid collecting device according to claim 1-2, characterized in that: The liquid chromatography tail liquid collection device also includes a detector, which is located after the multi-channel switching valve (4).

4. A liquid chromatography tail liquid collecting device according to claims 1-3, characterized in that: The liquid chromatography tail liquid collection device can accurately collect each chromatographic peak in the liquid chromatography by setting the inherent delayed dead time from the liquid chromatography detector (15) to the outlet of the multi-channel switching valve (4).

5. A liquid chromatography tail liquid collecting device according to claim 4, characterized in that: The inherent delayed dead time determination method is as follows: the emptied device is connected to the rear end of a liquid chromatography detector (15); the first three-way solenoid valve (1) is connected to the second three-way solenoid valve (2); the second three-way solenoid valve (2) is connected to the third three-way solenoid valve (3); the third three-way solenoid valve (3) is connected to a multi-channel switching valve (4); the liquid chromatography pump is turned on at a set flow rate and timing is started at the same time (T1); when the liquid flows out of the outlet of the multi-channel switching valve, the timing is stopped (T2); the time difference between the two is the delayed dead time (T2-T1).

6. A liquid chromatography tail liquid collecting device according to claim 4, characterized in that: The inherent delayed dead time is calculated based on the inherent dead volume and flow rate. The inherent dead volume is determined by completely draining the device, connecting a liquid pump before the first three-way solenoid valve (1), recording the weight of water (W1) before starting the liquid pump, connecting the first three-way solenoid valve (1) to the second three-way solenoid valve (2), connecting the second three-way solenoid valve (2) to the third three-way solenoid valve (3), connecting the third three-way solenoid valve (3) to the multi-channel switching valve (4), and starting the liquid pump. When liquid flows out of the outlet of the multi-channel switching valve (the outflow liquid returns to the source liquid), delay 10 seconds to allow complete filling, record the weight of the outflow liquid (W2) and the remaining water (W3), and the previous weight minus the remaining weight divided by the density of water 1.0 is the dead volume of the device ((W1-W2-W3) / 1.0).

Images