LC system and method using column back flushing

Abstract

A liquid chromatography (LC) system 100 is disclosed herein, comprising: at least one fluid stream 11, 12, 13, the at least one fluid stream 11, 12, 13 comprising at least one HPLC column; a downstream valve 20, the downstream valve 20 being connected to the at least one fluid stream 11, 12, 13 and connectable to a detector 60 via a valve-to-detector conduit 30, wherein the at least one fluid stream 11, 12, 13 is connectable to the valve-to-detector conduit 30 via the downstream valve 20, and wherein the LC system 100 further comprises a downstream pump 40, the downstream pump 40 being fluidly connected to the downstream valve 20 and connectable to the at least one fluid stream 11, 12, 13 via the downstream valve 20, so as to back-flush and thereby clean the at least one HPLC column. A corresponding automated LC method is also disclosed herein.

Description

Technical Field

[0001] The present disclosure relates to an automated liquid chromatography system and method including back flushing of a liquid chromatography column. Background Art

[0002] Automated in vitro diagnostic analyzers are common in clinical laboratories and hospital settings. These devices have become increasingly complex due to added functionality and increased sample throughput. As a result, errors and failures can occur in multiple device components, increasing the likelihood of reduced analyzer efficiency and / or reduced reliability of measurement results. In particular, there is a growing interest in implementing mass spectrometry (more specifically, liquid chromatography (LC) coupled with mass spectrometry) for in vitro diagnostics in clinical laboratories, which adds complexity and technical challenges when it comes to automation.

[0003] The heavy workload placed on certain components of the system, particularly the LC system, may require frequent maintenance procedures.

[0004] In particular, as the sample injection volume increases, HPLC columns may experience a continuous degradation in their performance, mainly due to particle accumulation at the column head, resulting in increased background, shifted retention times, shortened column life, increased costs, and the need for frequent maintenance.

[0005] Backflushing an HPLC column can result in higher sample throughput, more uptime, less maintenance, lower costs, higher data quality, and longer lasting calibration. This is typically done by manually disconnecting the column from the flow system and reconnecting the outlet side of the column to the flow inlet to reverse the direction of flow through the column, but the liquid flow from the column is typically directed to waste in order not to contaminate the detector. This manual procedure can take 15-20 minutes or more per column, followed by re-equilibration and quality control, before the column is reconnected in its original orientation with the correct flow direction.

[0006] This manual procedure is laborious, time-consuming and requires intervention by external maintenance personnel or laboratory technicians, during which the analyzer or its components may be unavailable, incurring additional costs and introducing the risk of errors and malfunctions or even system damage. Summary of the invention

[0007] Against the foregoing background, embodiments of the present disclosure provide certain non-obvious advantages and advances over the prior art.In particular, the inventors have recognized a need for improvements in LC systems and methods that include column backflushing.

[0008] Although the embodiments of the present disclosure are not limited to specific advantages or functionality, it should be noted that the present disclosure provides an LC system and method that, among other functions, can also achieve automated HPLC column backwashing, thereby ensuring continued analytical performance of the system and extended HPLC column life, without the need for manual intervention, and thus improving user convenience. Other advantages are as follows: minimize system downtime, reduce costs, and eliminate the risk of errors, failures, and system damage.

[0009] In particular, a liquid chromatography (LC) system disclosed herein comprises: at least one fluid stream, the at least one fluid stream comprising at least one HPLC column; a downstream valve connected to the at least one fluid stream and connectable to a detector via a valve-to-detector conduit, wherein the at least one fluid stream is connectable to the valve-to-detector conduit via the downstream valve. The LC system further comprises a downstream pump, the downstream pump being fluidly connected to the downstream valve and connectable to the at least one fluid stream via the downstream valve, so as to back-flush and thereby clean the at least one HPLC column.

[0010] "Liquid chromatography or LC" is an analytical process that subjects a sample injected by a sample injector to chromatographic separation through an LC column in order to, for example, separate target analytes from matrix components, such as those remaining after sample preparation, which may still interfere with subsequent detection, such as mass spectrometry, and / or to separate target analytes from each other so that they can be detected separately. "High performance liquid chromatography" or HPLC, "ultra-high performance liquid chromatography" or UHPLC, "micro-liquid chromatography" or μLC, and "small-bore liquid chromatography" or small-bore LC are forms of liquid chromatography performed under pressure.

[0011] A "liquid chromatography system or LC system" is an analytical device or a module or unit in an analytical device for performing liquid chromatography analysis. An LC system may be embodied as a single channel system with one fluid stream or as a multichannel system with multiple fluid streams, which system may include one or more LC columns arranged in parallel and / or in series. An LC system may also include elements such as injectors, valves, liquid sources, fluid connections and components (e.g., for mixing liquids, degassing liquids, tempering liquids, etc.), one or more sensors (such as pressure sensors, temperature sensors, etc.), and in particular at least one LC pump. This list is not exhaustive.

[0012] According to an embodiment, the detector can be a mass spectrometer connected to the valve-to-detector conduit via an ionization source. However, the detector can be other instruments other than a mass spectrometer, such as an optical detector (e.g., a UV or fluorescence detector), an impedance detector, a conductivity detector, etc.

[0013] According to an embodiment, the LC system can be configured as an analysis module designed to prepare samples for mass spectrometry analysis and / or transfer prepared samples to a mass spectrometer, particularly for separating target analytes prior to detection by the mass spectrometer. Specifically, typically, during an LC run, the mass spectrometer can be set to scan a specific mass range. LC / MS data can be represented by adding the ion currents in the individual mass scans and plotting the "total" ion current as a plot of intensity points versus time. The resulting graph looks like an HPLC-UV trace with analyte peaks.

[0014] A "fluid stream" is a fluid path through which a liquid can flow; in particular, through which a sample from a sample injection point can be transferred to a detector (e.g., to a mass spectrometer or other detector); and through which a sample can undergo a chromatographic process. Fluid connections through different parts of the fluid stream can be discontinuous. This is because the fluid stream may include elements such as switch valves that can establish alternative connections and regulate fluid flow between different parts of the fluid stream at different times. The fluid stream may include at least one LC column. The at least one LC column may be interchangeable. In particular, the LC system may include more LC columns than fluid streams, wherein multiple LC columns may be selectable, for example interchangeably coupled to the same fluid stream. Capillaries may also be used to bypass LC columns. The fluid stream may include multiple substreams.

[0015] In particular, according to one or more embodiments of the present disclosure, an LC system may include multiple fluid streams connected to a downstream valve for directing flow from one fluid stream at a time to a detector.

[0016] "LC column" may refer to any of a column, cartridge, capillary, etc., used to perform separations of a chromatographic nature. The column is typically filled or loaded with a stationary phase through which a mobile phase is pumped to capture and / or separate and elute and / or transfer target analytes under selected conditions (e.g., based on the polarity or log P value, size or affinity of the target analyte, as is well known). The stationary phase may be particulate or beaded or a porous monolith. However, the term "column" may also refer to a capillary or channel that is not filled or loaded with a stationary phase but instead relies on the surface area of ​​the inner capillary wall or geometry to achieve separation. Column array chromatography provides an example in which the separation bed is formed by etching away the interstitial volume on a solid silicon wafer, leaving an array of columns. The resulting channels can be folded onto a smaller footprint by connecting the bed segments in series using optimized flow distributors that limit peak dispersion. This creates a stationary phase support structure that is organized in a reproducible, ordered pattern.

[0017] The LC column can be interchangeable with one or more other LC columns and / or operated in parallel or sequentially. The LC column can be, for example, a fast capture and elution LC column (or simply a "capture column"), an HPLC column or a UHPLC column, and can be a column of any size, including a micro LC column and a small-bore LC column, or a column array LC column. In the case of a capture column, a stationary phase can be selected that retains the target analyte, while any salts, buffers, detergents and other matrix components will not be retained and will be washed away. After this process, the analytes are usually eluted with a different mobile phase or solvent gradient, for example, in a backwash mode. Depending on the analyte, some analytes can be separated in some cases. On the other hand, if the analytes have the same mass (isobaric elements) and / or the ion spectra overlap in multiple reaction monitoring (MRM), a more extensive chromatographic separation is desirable when it comes to mass spectrometry. In this case, it may be advantageous to perform the separation in an HPLC or UHPLC column.

[0018] For purposes of the present disclosure, the at least one fluid flow comprises at least one HPLC column (where, for simplicity, the term "HPLC" may also include UHPLC or other high performance columns such as μ-LC and small pore columns), which, unlike a fast trap and elute LC column, does not typically undergo backflushing during an analytical run and typically requires manual intervention by disconnecting the column, reversing the direction of flow by reconnecting the column in a reverse orientation, and directing the flow to waste rather than to a detector in order to backflush the column for the sole purpose of washing the column.

[0019] A "liquid chromatography pump or LC pump" is a high-pressure pump that can vary in pressure capacity but produces a consistent and reproducible volume flow through an LC channel. Pressures in HPLC can typically be up to 60 MPa or about 600 atmospheres, while UHPLC and μ-LC systems have been developed to operate at even higher pressures (e.g. up to 140 MPa or about 1400 atmospheres), thus enabling the use of much smaller particle sizes (<2 μm) in LC columns. LC pumps can be configured as binary pumps or even quaternary pumps, for example, in cases where an elution gradient needs to be used by gradually changing the ratios between up to four elution solvents.

[0020] According to one embodiment, the LC pump may generate a pressure of 60 MPa to 140 MPa (typically 75 MPa to 100 MPa, and more typically 80 MPa).

[0021] According to one embodiment, the LC pump may be configured to operate at a flow rate between 1 μl / min and 500 μl / min or greater (typically up to 1500 μl / min), and more typically between 100 μl / min and 300 μl / min and with an accuracy of, for example, about ±5% or less.

[0022] The LC pump may include more than one pump head. For example, a binary pump includes two pump heads, and each pump head typically includes a primary pump head and a secondary pump head that cooperate with each other to pump liquid while maintaining a liquid pressure in the pump head approximately constant. In particular, each of the primary pump head and the secondary pump head is typically a syringe pump that includes a syringe-like cylinder having an inner wall surface and a plunger plug that can be translated through the cylinder, the plunger plug translating through the cylinder leaving a gap between the inner wall surface and the plunger plug.

[0023] The term "liquid" with respect to a fluid stream refers to a liquid commonly used in liquid chromatography, eg as a solvent or a mixture of solvents used, eg as a mobile phase or eluent (elution solvent), and is known in the art.

[0024] "Downstream pump" is an auxiliary pump that is different from the LC pump at least in terms of function, and may be a multifunctional pump, including at least backwashing at least one HPLC column to clean it. Another possible function is to promote and accelerate the liquid exchange in the valve-to-detector conduit. In general, compared with the LC pump, the downstream pump is a low-pressure and high-volume (high flow rate) pump, which is fluidically connected to the downstream valve. Generally, according to the present disclosure, the downstream pump is also a low-precision pump, so it has a simpler structure and a lower price compared to the LC pump. According to an embodiment of the present disclosure, the downstream pump is a positive pressure pump. Via the fluid selection valve, any pump suitable for generating positive pressure can be used to actively extract washing liquid or mobile phase from the at least one HPLC column in the backwashing and / or through the valve-to-detector conduit. The liquid source, for example, a membrane pump / diaphragm pump, a single plunger high-speed pump, a syringe piston pump, a gear pump, etc. According to an embodiment, positive pressure and active extraction can be achieved by applying pneumatic pressure (e.g., by compressed gas, such as by a nitrogen source) to a sealed liquid container connected to the upstream air inlet valve.

[0025] According to an embodiment, the downstream pump is configured to extract the wash solution through the HPLC column and / or the valve-to-detector conduit at a flow rate higher than the fluid flow (e.g., several times higher, e.g., 5 times, 10 times, 20 times or more). For example, if it is a μ-LC with a typical flow rate of about 1 μL / min, a wash pump flow rate of 5 μL / min is already advantageous. If the flow rate of the fluid flow is about 100 μL / min, the effective flow rate of the downstream pump can be about 500 μL / min to 1000 μL / min or higher. According to some embodiments, a flow rate of up to 5000 μL / min of the downstream pump is possible. The flow rate can be variable, depending on whether the wash solution is directed to the HPLC column or the valve-to-detector conduit.

[0026] "Washing liquid" can be a liquid suitable for washing away and eventually dissolving the particles, adsorbed matrix components, etc. accumulated on the HPLC column head during multiple sample injection cycles. Washing liquid can be a liquid suitable for washing away and eventually dissolving the final traces of the sample from the valve-to-detector conduit, while also being compatible with the detector used (e.g., mass spectrometer). Washing liquid can be the same or similar to the eluting solvent used for chromatographic analysis, depending on the type of column, or the type of sample and the analyte passing through the column may be different. For example, for the analyte that is usually used for reverse phase chromatography, a suitable solvent can be an organic solvent, such as methanol, acetonitrile, tetrahydrofuran, and / or isopropanol. These solvents can also be mixed with each other and / or mixed with water. Acidic or alkaline additives can be added to adjust pH. Commonly used additives can include formic acid, ammonium formate, ammonium acetate, etc. For example, for the analyte that is usually used for normal phase chromatography, a suitable solvent can include heptane, chloroform, or 2-propanol mixed with a polar organic solvent (such as ethyl acetate). The wash fluids can be the same or different for backflushing the HPLC column and for washing the valve-to-detector conduit, respectively, depending on the HPLC column.

[0027] The term "valve" refers to a flow regulating device that controls, redirects, limits or cuts off a flow, particularly an LC switch valve, i.e., a porous valve that controls the flow between elements connected to a hole. This is usually achieved by moving one or more valve conduits to switch the communication between different elements. The element can be fluidly connected to the hole via another conduit (such as a pipe, a tube, a capillary, a microfluidic channel, etc.) and by fittings (such as screws / nuts and ferrules) or alternative liquid-tight seals, for example, held in place by a clamping mechanism. LC switch valves are generally capable of allowing liquid pressures to reach the order of magnitude used for HPLC or higher.

[0028] In particular, a "downstream valve" is an LC switching valve located downstream relative to the at least one HPLC column in the normal direction from the HPLC column to the detector. The downstream valve may include a hole for each fluid flow, a hole for the valve-to-detector conduit, one or more downstream pump holes, and one or more waste holes.

[0029] According to an embodiment, the downstream valve has an inner valve conduit with an inner diameter less than 0.6 mm, typically between about 0.5 mm and 0.2 mm, more typically about 0.4 mm, even more typically about 0.25 mm. However, the inner valve conduit may have other diameters within the commonly used range.

[0030] According to an embodiment, the downstream valve has a standard switching time of approximately 500 ms or less. However, the switching time can also be longer than 500 ms.

[0031] According to an embodiment, the LC system comprises a plurality of fluid streams connectable to the valve-to-detector conduit, optionally via a downstream valve.

[0032] According to an embodiment, a downstream pump may also be connected to the valve-to-detector conduit via the downstream valve in order to wash the valve-to-detector conduit.

[0033] According to an embodiment, a downstream pump is configured to be connected to a valve-to-detector conduit between two consecutive fluid flows so as to wash liquid from a previous fluid flow flowing out of the valve-to-detector conduit before liquid from a subsequent fluid flow enters the valve-to-detector conduit.

[0034] According to an embodiment, the downstream pump is connected to the downstream valve via a wash selector valve, wherein the wash selector valve is configured to be alternatively connected to any one of the at least one fluid flow via the downstream valve and to the valve-to-detector conduit.

[0035] The "wash selector valve" is an LC switching valve located between the downstream pump and the downstream valve, and includes a downstream pump inlet port, a wash outlet port for each backflushed fluid flow, wherein the fluid connection between the outlet ports and the corresponding fluid flows is made via the downstream valve, and finally via the downstream valve a waste outlet port connectable to the valve-to-detector conduit.

[0036] According to an embodiment, the wash select valve is connectable to the at least one fluid flow via a respective three-way valve fluidly connected to the downstream valve, the three-way valve comprising a wash select valve inlet aperture, a downstream valve outlet aperture and a waste outlet aperture.

[0037] The LC system may include a controller configured to automatically backflush the at least one HPLC column at regular times and / or upon detecting a pressure rise in the at least one fluid stream above a predetermined threshold and / or upon detecting a performance degradation below a predetermined threshold, for example, by monitoring data such as an increase in signal background, changes in analyte retention time, changes in peak shape, etc. when using the at least one HPLC column.

[0038] According to an embodiment, the controller is further configured to manage, by controlling any one or more of the downstream valves, the wash selection valve, and the three-way valve: the fluid flow-detector connection time, i.e., the connection time between the at least one fluid flow and the valve-to-detector conduit; the downstream pump-detector connection time, i.e., the connection time between the downstream pump and the valve-to-detector conduit; and the downstream pump-fluid flow connection time, i.e., the connection time between the at least one fluid flow and the downstream pump.

[0039] According to an embodiment, the fluid flow-to-detector connection time is fixed and is the same for each fluid flow. In addition, the downstream pump-to-detector connection time is fixed and is a part of the fluid flow-to-detector connection time, so that continuous switching operation is performed at least temporarily at a fixed speed. If the downstream pump-to-detector connection time is 20% or less (typically 10% or less, or more typically 5% or less) of the fluid flow-to-detector connection time, this may be particularly beneficial for the downstream pump to adjust conditions such as flow rate and / or washing liquid to minimize the downstream pump-to-detector connection time. In absolute terms, the downstream pump-to-detector connection time can be as short as a few seconds, typically 5s or less, more typically 3s or less.

[0040] As used herein, the term "controller" may refer to a central processing unit (such as a microprocessor), a microcontroller, a reduced instruction set circuit (RISC), an application-specific integrated circuit (ASIC), a logic circuit, and any other circuit or processor capable of performing the functions / methods described herein.

[0041] The controller may be integrated into the analysis system, or may be an independent logical entity that communicates with the analysis system via a direct connection, either wired or wireless, or indirectly via a communication network (e.g., a wide area network, such as the Internet or a local area network or intranet of a health care provider) via a network interface device, either wired or wireless. In some embodiments, the processor may be integrated with the data management unit, for example, implemented on a computing device (such as a desktop computer, a laptop, a smart phone, a tablet computer, a PDA, etc.). The processor may be composed of a server computer and / or distributed / shared across / among multiple analysis systems. In addition, the analysis system may include a communication interface, such as a wireless, wireless, infrared, cellular, ) remote devices, servers and cloud-based elements that communicate with the controller or communicate via a remote PC / server or cloud-based system. The controller can also be configured to control the analysis system so that the workflow and workflow steps are performed by the analysis system. In particular, the processor can communicate and / or cooperate with the scheduler and / or data manager to take into account the incoming test commands and / or received test commands and a large number of predetermined process operations associated with executing the test commands and manage the different connection times and the opening and closing of valves.

[0042] According to another embodiment of the present disclosure, an automated LC method is also disclosed herein, which includes fluidically connecting at least one fluid flow including at least one HPLC column to a downstream valve so as to connect the at least one fluid flow to a detector via a valve-to-detector conduit; the method further includes (via a downstream valve) fluidly connecting a downstream pump to the at least one fluid flow so as to back-flush and thereby clean the at least one HPLC column.

[0043] According to an embodiment, the LC method comprises connecting a plurality of fluid streams to the valve-to-detector conduit, optionally via a downstream valve.

[0044] According to an embodiment, the LC method comprises connecting a downstream pump to the valve-to-detector conduit via a downstream valve in order to purge the valve-to-detector conduit.

[0045] According to an embodiment, an LC method includes connecting a downstream pump to a valve-to-detector conduit between two consecutive fluid flows so as to wash liquid from a previous fluid flow flowing out of the valve-to-detector conduit before liquid from a subsequent fluid flow enters the valve-to-detector conduit.

[0046] According to an embodiment, the LC method comprises connecting a downstream pump to the downstream valve via a wash selection valve, and alternatively connecting the wash selection valve to any one of the at least one fluid stream and to the valve-to-detector conduit via the downstream valve.

[0047] According to an embodiment, the LC method comprises connecting a wash select valve to the at least one fluid stream via a corresponding three-way valve fluidly connected to a downstream valve, the three-way valve comprising a wash select valve inlet aperture, a downstream valve outlet aperture and a waste outlet aperture.

[0048] According to an embodiment, the LC method includes automatically backflushing the at least one HPLC column at regular times and / or upon detecting a pressure rise in the at least one fluid stream above a predetermined threshold and / or upon detecting a performance drop below a predetermined threshold, for example, by monitoring data such as signal background increase, analyte retention time change, peak shape change, etc. when using the at least one HPLC column.

[0049] According to an embodiment, the LC method includes automatically managing, by a controller, switching on or off any one or more of a downstream valve, a wash selection valve, and a three-way valve: a fluid flow-detector connection time, i.e., a connection time between the at least one fluid flow and a valve-to-detector conduit; a downstream pump-detector connection time, i.e., a connection time between the downstream pump and the valve-to-detector conduit; and a downstream pump-fluid flow connection time, i.e., a connection time between the at least one fluid flow and the downstream pump.

[0050] According to an embodiment, the method may further include automatically managing: the fluid flow connection time, i.e., the connection time between each fluid flow and the valve-to-detector conduit; and the washing pump connection time, i.e., the connection time between the washing pump and the valve-to-detector conduit by controlling the switching of the flow selection valve.

[0051] According to another embodiment, the fluid flow connection time may be fixed and the same for each fluid flow, and wherein the wash pump connection time is fixed and is a fraction of the fluid flow connection time, thereby at least temporarily performing a continuous on-off operation at a fixed speed.

[0052] Other and further objects, features and advantages will appear from the following description of exemplary embodiments in conjunction with the accompanying drawings and the appended claims.It should be noted that the scope of the claims is defined by the references therein rather than by the specific discussion of the features and advantages set forth in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The following detailed description of embodiments of the present disclosure may be best understood when read in conjunction with the following drawings, in which like structures are represented by like reference numerals, and in which:

[0054] Figure 1A Schematically shown is an LC system comprising a downstream pump connected to a downstream valve and a first step of an LC method comprising using the downstream pump.

[0055] Figure 1B Schematically shows Figure 1A The same LC system and the second step of the same method were used.

[0056] Figure 1C Schematically shows Figure 1A The same LC system and the third step of the same method were used.

[0057] Figure 1D Schematically shows Figure 1A The same LC system and the fourth step of the same method are Figure 1B The LC system and method were the same.

[0058] Figure 1E Schematically shows Figure 1A The same LC system and the fifth step of the same method were used.

[0059] Figure 1F Schematically shows Figure 1A The same LC system and the same method step 6 in Figure 1B and Figure 1D The LC system and method were the same.

[0060] Figure 2A Schematically shows Figures 1A to 1F The same LC system in FIG. 1 and the first step of a method for backflushing the fluid flow using a downstream pump.

[0061] Figure 2B Schematically shows Figure 2A The same LC system and the second step of the same method were used.

[0062] Figure 2C Schematically shows Figure 2A The same LC system and the third step of the same method were used.

[0063] Figure 3A Schematically shows Figures 1A to 1E Further aspects of the LC systems and methods.

[0064] Figure 3B Schematically shows Figure 3A The same LC system in FIG. 2A to FIG. 2C Further aspects of the method.

[0065] The skilled person will appreciate that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size of some elements in the drawings may be magnified relative to other elements to help enhance understanding of the embodiments of the present disclosure. DETAILED DESCRIPTION

[0066] Combination Figures 1A to 1F as well as FIG. 2A to FIG. 2C A schematic example of a liquid chromatography (LC) system 100 is shown, the system comprising a plurality of fluid streams 11, 12, 13 optionally connectable to a common detector 60 via a downstream valve 20, the downstream valve being connected to the detector 60 via a valve-to-detector conduit 30, each fluid stream 11, 12, 13 comprising at least one HPLC column. The LC system 100 further comprises a downstream pump 40 fluidly connected to the downstream valve 20, the downstream pump being configured to be connected to the valve-to-detector conduit 30 between two consecutive fluid streams 11, 12; 12, 13; 13, 11 so as to wash liquid from a preceding fluid stream flowing out of the valve-to-detector conduit 30 before liquid from a subsequent fluid stream enters the valve-to-detector conduit 30.

[0067] In particular, in this case, the downstream valve 20 comprises: a fluid flow hole 21, 22, 23 for each fluid stream 11, 12, 13, respectively; and a waste hole 21', 22', 23' for each fluid stream 11, 12, 13, respectively, and leading to the waste 50, wherein the waste hole 21', 22', 23' can function as a downstream pump inlet hole 21', 22', 23' connectable to the fluid stream 11, 12, 13, respectively, via the downstream pump inlet hole 21', 22', 23', for backflushing and thus cleaning the fluid stream 11, 12, 13. The downstream valve 20 further comprises a valve-to-detector conduit hole 25, which is connected to the valve-to-detector conduit 30 and alternatively connectable to each of the fluid streams 11, 12, 13, respectively, via the fluid flow holes 21, 22, 23. The downstream valve 20 further comprises an additional downstream pump inlet port 24 which can also be connected to the valve-to-detector conduit 30 via the valve-to-detector conduit port 25, and a downstream pump waste port 24' which when connected to the downstream pump inlet port 24 leads to the waste 50. It should be clear that this is only an example, and the number of ports and connections as well as the order of switching between fluid flows can be adjusted as required and according to the number of fluid flows.

[0068] In this example, the downstream pump 40 is connected to four wash liquid containers, which contain corresponding wash liquids 41, 42, 43, 44, such as, for example, water, acetonitrile, methanol, tetrahydrofuran or isopropanol, which can be drawn alone or mixed with each other in any combination and ratio, depending on, for example, LC conditions, type of HPLC column, kind of sample and / or analyte flowing therein, and desired washing effect. In particular, the wash pump 40 can be configured to use the corresponding upstream LC pump (not shown). Figures 1A to 1F as well as FIG. 2A to FIG. 2C ) is drawn through the valve-to-detector conduit 30 and / or through the fluid streams 11 , 12 , 13 in backwash mode at a flow rate 45 that is higher than the flow rate 15 of the fluid streams 11 , 12 , 13 .

[0069] The downstream pump 40 is connected to the downstream valve 20 via a wash selection valve 70. The wash selection valve 70 is configured to alternatively connect the downstream pump 40 to any one of the fluid streams 11, 12, 13 via the downstream valve 20 and to the valve-to-detector conduit 30. In particular, the wash selection valve 70 is connectable to the fluid streams 11, 12, 13 via fluid stream wash holes 71, 72, 73 leading to the respective three-way valves 16, 17, 18, the three-way valves being fluidly connected to the downstream valve 20 via the downstream pump inlet holes 21', 22', 23', respectively, each of the three-way valves 16, 17, 18 including a wash selection valve inlet hole, a downstream valve outlet hole, and a waste outlet hole leading to the waste 50. The wash selection valve 70 further includes a valve-to-detector conduit wash hole 74 connected to the downstream valve 20 via the downstream pump inlet hole 24.

[0070] The LC system 100 further comprises a controller 90 configured to automatically back-flush the HPLC columns of the respective fluid streams 11, 12, 13 at regular times and / or upon detecting a pressure rise in the at least one fluid stream above a predetermined threshold and / or upon detecting a performance drop below a predetermined threshold.

[0071] The controller 90 is further configured to manage, by controlling the downstream valve 20, the wash selection valve 70, the three-way valves 16, 17, and 18: the fluid flow-detector connection time, i.e., the connection time between the fluid flows 11, 12, 13 and the valve-to-detector conduit 30; the downstream pump-detector connection time, i.e., the connection time between the downstream pump 40 and the valve-to-detector conduit 30; and the downstream pump-fluid flow connection time, i.e., the connection time between the fluid flows 11, 12, 13 and the downstream pump 40.

[0072] Continue to combine Figures 1A to 1F as well as FIG. 2A to FIG. 2C A LC method is schematically shown, the method comprising fluidly connecting at least one fluid stream 11, 12, 13 comprising at least one HPLC column to a downstream valve 20 so as to connect the at least one fluid stream 11, 12, 13 to a detector 60 via a valve-to-detector conduit 30; the method further comprises fluidly connecting a downstream pump 40 to the at least one fluid stream 11, 12, 13 via the downstream valve 20 so as to back-flush and thereby clean the at least one HPLC column.

[0073] The LC method further comprises connecting the plurality of fluid streams 11 , 12 , 13 to a valve-to-detector conduit 30 , optionally via a downstream valve 20 .

[0074] The LC method further comprises connecting a downstream pump 40 to the valve-to-detector conduit 30 via the downstream valve 20 in order to wash the valve-to-detector conduit 30 .

[0075] The LC method further includes connecting a downstream pump 40 to a valve-to-detector conduit 30 between two consecutive fluid streams 11, 12; 12, 13; 13, 11 so as to wash liquid in a previous fluid stream flowing out of the valve-to-detector conduit 30 before liquid from a subsequent fluid stream enters the valve-to-detector conduit 30.

[0076] The LC method further comprises connecting the downstream pump 40 to the downstream valve 20 via the wash selector valve 70 , and alternatively connecting the wash selector valve 70 to any one of the at least one fluid stream 11 , 12 , 13 and to the valve-to-detector conduit 30 via the downstream valve 20 .

[0077] In particular, the LC method comprises connecting a wash selector valve 70 to the at least one fluid stream 11, 12, 13 via a respective three-way valve 16, 17, 18 fluidly connected to the downstream valve 20, the three-way valve 16, 17, 18 comprising a wash selector valve inlet port, a downstream valve outlet port and a waste outlet port.

[0078] According to an embodiment, the LC method further comprises automatically backflushing the at least one HPLC column at regular times and / or upon detecting a pressure rise in the at least one fluid stream above a predetermined threshold and / or upon detecting a performance drop of the at least one HPLC column below a predetermined threshold.

[0079] The LC method may further include automatically managing, by means of the controller 90, the switching of one or more of the downstream valve 20, the wash selection valve 70, the three-way valves 16, 17, 18: the fluid flow-to-detector connection time, i.e., the connection time between the at least one fluid flow 11, 12, 13 and the valve-to-detector conduit 30; the downstream pump-detector connection time, i.e., the connection time between the downstream pump 40 and the valve-to-detector conduit 30; and the downstream pump-fluid flow connection time, i.e., the connection time between at least one fluid flow 11, 12, 13 and the downstream pump 40.

[0080] In particular, Figure 1A The first step of the method is shown, wherein the downstream valve 20 is switched to connect and direct fluid stream 11 to the valve-to-detector conduit 30, but direct the other fluid streams 12, 13 to waste 50 via waste ports 22', 23' and three-way valves 17, 18, respectively. Wash fluid from the downstream pump 40 is also directed to waste 50 via the downstream valve 20, the wash selection valve 70 is connected to the downstream pump inlet port 24 via the valve-to-detector conduit wash port 74, and the downstream pump inlet port 24 is connected to the downstream pump waste port 24'.

[0081] Figure 1BThe second step of the method is shown, in which the downstream valve 20 is switched to connect the downstream pump 40 to the valve-to-detector conduit 30 by connecting the downstream pump inlet port 24 directly to the valve-to-detector conduit port 25, but directing all fluid flows 11, 12, 13 to waste 50 via waste ports 21', 22', 23' and three-way valves 16, 17, 18, respectively.

[0082] Figure 1C The third step of the method is shown, in which the downstream valve 20 is switched to connect the fluid stream 12 to the valve-to-detector conduit 30, but direct the other fluid streams 11, 13 to waste 50 via waste ports 21', 23' and three-way valves 16, 18, respectively. Figure 1A The downstream pump waste port 24 ′ of the downstream valve 20 is shown to direct wash fluid from the downstream pump 40 to waste 50 as well.

[0083] Figure 1D The fourth step of the method shown is the same as Figure 1B The second step is the same as in .

[0084] Figure 1E The fifth step of the method is shown, in which the downstream valve 20 is switched to connect the fluid stream 13 to the valve-to-detector conduit 30, but direct the other fluid streams 11, 12 to waste 50 via waste ports 21', 22' and three-way valves 16, 17, respectively. Figure 1A and Figure 1C The downstream pump waste port 24 ′ of the downstream valve 20 is shown to direct wash fluid from the downstream pump 40 to waste 50 as well.

[0085] In from Figure 1A The first step before starting from scratch, Figure 1F The sixth step of the method shown is Figure 1B The second step and Figure 1B Same as step 4 in .

[0086] Figure 2A A further step of the method is schematically shown, in which the downstream pump 40 is used to backwash the fluid flow 11. In particular, the wash selection valve 70, the downstream valve 20 and the three-way valve 16 are switched so that the downstream pump 40 is connected to the fluid flow 11 via the fluid flow wash hole 71, the three-way valve 16, the downstream pump inlet hole 21' and the fluid flow hole 21. At the same time, the fluid flow 12 is connected to the valve-to-detector conduit 30 via the fluid flow hole 22 and the valve-to-detector conduit 25, but the fluid flow 13 is directed to the waste 50 via the fluid flow hole 23, the waste hole 23' and the three-way valve 18, respectively. It should be noted that the flow direction 15 of the fluid flow 11 is Figure 2A In the reverse direction.

[0087] Figure 2BA further step of the method is schematically shown, in which the downstream pump 40 is used to backwash the fluid flow 12. In particular, the wash selection valve 70, the downstream valve 20 and the three-way valve 17 are switched so that the downstream pump 40 is connected to the fluid flow 12 via the fluid flow wash hole 72, the three-way valve 17, the downstream pump inlet hole 22' and the fluid flow hole 22. At the same time, the fluid flow 11 is connected to the valve-to-detector conduit 30 via the fluid flow hole 21 and the valve-to-detector conduit 25, but the fluid flow 13 is directed to the waste 50 via the fluid flow hole 23, the waste hole 23' and the three-way valve 18, respectively. It should be noted that the flow direction 15 of the fluid flow 12 is Figure 2B In the reverse direction.

[0088] Figure 2C A further step of the method is schematically shown, in which the downstream pump 40 is used to backwash the fluid flow 13. In particular, the wash selection valve 70, the downstream valve 20 and the three-way valve 18 are switched so that the downstream pump 40 is connected to the fluid flow 13 via the fluid flow wash hole 73, the three-way valve 18, the downstream pump inlet hole 23' and the fluid flow hole 23. At the same time, the fluid flow 11 is connected to the valve-to-detector conduit 30 via the fluid flow hole 21 and the valve-to-detector conduit 25, but the fluid flow 12 is directed to the waste 50 via the fluid flow hole 22, the waste hole 22' and the three-way valve 17, respectively. It should be noted that the flow direction 15 of the fluid flow 13 is in Figure 2C In the reverse direction.

[0089] Figure 3A Schematically shows Figures 1A-1E In particular, the LC system 100 further comprises a flow cell for each fluid stream 11 (for simplicity, Figure 3A 1 , an upstream LC pump 10 for a fluid flow (only one fluid flow is shown), in particular comprising a binary LC pump, comprising two pump heads 9, 9' merging into a fluid flow 11 via an upstream valve 8. In this example, the upstream pump 8 is implemented as an 8-port / two-way valve, comprising two upstream pump inlet ports 1, 1' fluidly connected to the pump heads 9, 9', respectively, two upstream pump outlet ports 2, 2' leading to the fluid flow 11, two upstream pump waste ports 3, 3' respectively directing the liquid drawn by the pump heads 9, 9' to waste 50, and two back-flushing waste ports 4, 4'. Figure 3A The method comprises switching the upstream valve 8 such that the upstream pump inlet apertures 1 , 1 ′ are connected to the upstream pump outlets 2 , 2 ′, respectively, so as to direct the liquid flow from the upstream LC pump 10 via the upstream valve 8 in the normal flow direction 15 to the fluid stream 1 .

[0090] Figure 3B Schematically shows Figure 3A The same LC system 100 and Figures 2A-2CIn particular, the method comprises switching the upstream valve 8 so that the upstream pump inlet holes 1, 1' are connected to the upstream pump waste holes 3, 3', respectively, so as to guide the liquid pumped by the pump heads 9, 9' to the waste. In addition, the upstream pump outlet holes 2, 2' are connected to the backwash waste holes 4, 4', respectively, so as to guide the liquid flow from the downstream pump via the fluid flow 11 in the reverse flow direction 15 to the waste 50.

[0091] In the foregoing description, many specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it is apparent to one of ordinary skill in the art that specific details are not required to practice what is taught herein. In other cases, well-known materials or methods are not described in detail to avoid obscuring the present disclosure.

[0092] In particular, modifications and variations of the disclosed embodiments are of course possible in light of the above description. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced in a manner other than that specifically designed in the above examples.

[0093] Throughout this specification, references to "one embodiment", "an embodiment", "an example" or "an instance", "an aspect" or "an aspect" mean that the specific features, structures or characteristics described in connection with the embodiment, example or aspect are included in at least one embodiment. Therefore, the phrases "in one embodiment" or "in an embodiment", "an example" or "an instance", "an aspect" or "an aspect" appearing in various places throughout this specification do not necessarily all refer to the same embodiment, example or aspect.

[0094] Furthermore, the particular features, structures or characteristics may be combined in any suitable combinations and / or sub-combinations in one or more embodiments or examples or aspects.

Claims

1. A liquid chromatography (LC) system (100), comprising - a plurality of fluid streams (11, 12, 13), said fluid streams (11, 12, 13) comprising at least one HPLC column distinct from a fast trapping and elution LC column, a downstream valve (20) connected to the fluid flow (11, 12, 13) and connectable to a detector (60) via a valve-to-detector conduit (30), wherein the fluid flow (11, 12, 13) is alternatively connectable to the valve-to-detector conduit (30) via the downstream valve (20), in The LC system (100) further comprises a downstream pump (40) which is fluidically connected to the downstream valve (20) and optionally connectable to the fluid stream (11, 12, 13) via the downstream valve (20) for backflushing and thereby cleaning the at least one HPLC column, and which is also connectable to the valve-to-detector conduit (30) via the downstream valve (20) for washing the valve-to-detector conduit (30), wherein the downstream pump (40) is configured to be connected to the valve-to-detector conduit (30) between two consecutive fluid streams in order to wash liquid from a preceding fluid stream flowing out of the valve-to-detector conduit (30) before liquid from a subsequent fluid stream enters the valve-to-detector conduit (30), wherein the downstream pump (40) is connected to the downstream valve (20) via a wash selection valve (70), and wherein the wash selection valve (70) is configured to optionally connect to the valve-to-detector conduit (30) via the downstream valve (20) Connected to any one of the fluid streams (11, 12, 13) and to the valve-to-detector conduit (30).

2. The LC system (100) according to claim 1, wherein the wash selection valve (70) is connectable to the fluid stream (11, 12, 13) via a corresponding three-way valve (16, 17, 18) fluidly connected to the downstream valve (20), the three-way valve (16, 17, 18) comprising a wash selection valve inlet port, a downstream valve outlet port, and a waste outlet port.

3. The LC system (100) according to claim 2, comprising a controller (90), which is configured to automatically backflush the at least one HPLC column at regular intervals and / or upon detecting a pressure rise in the fluid flow above a predetermined threshold and / or upon detecting a performance drop of the at least one HPLC column below a predetermined threshold.

4. The LC system (100) according to claim 3, wherein the controller (90) is further configured to manage the fluid flow-to-detector connection time, i.e., the connection time between the fluid flow (11, 12, 13) and the valve-to-detector conduit (30), the downstream pump-to-detector connection time, i.e., the connection time between the downstream pump (40) and the valve-to-detector conduit (30), and the downstream pump-to-fluid flow connection time, i.e., the connection time between the fluid flow (11, 12, 13) and the downstream pump (40), by controlling the switching of any one or more of the downstream valve (20), the wash selection valve (70), and the three-way valve (16, 17, 18).

5. The LC system (100) according to claim 1, comprising a controller (90), wherein the controller (90) is configured to automatically backflush the at least one HPLC column at regular intervals and / or upon detecting a pressure rise in the fluid flow above a predetermined threshold and / or upon detecting a performance drop of the at least one HPLC column below a predetermined threshold.

6. An automated LC method, the method comprising fluidly connecting a plurality of fluid streams (11, 12, 13) comprising at least one HPLC column distinct from a fast trap and elution LC column to a downstream valve (20) for connecting the fluid streams (11, 12, 13) to a detector (60) optionally via a valve-to-detector conduit (30), the method further comprising fluidly connecting a downstream pump (40) to the fluid streams (11, 12, 13) optionally via the downstream valve (20) for backflushing and thereby cleaning the at least one HPLC column, and connecting the downstream pump (40) to the valve-to-detector conduit (30) in order to wash the valve-to-detector conduit (30), The method comprises connecting the downstream pump (40) to the valve-to-detector conduit (30) between two consecutive fluid flows so as to wash liquid from a previous fluid flow flowing out of the valve-to-detector conduit (30) before liquid from a subsequent fluid flow enters the valve-to-detector conduit (30), the method further comprising connecting the downstream pump (40) to the downstream valve (20) via a wash selection valve (70), and alternatively connecting the wash selection valve (70) to any one of the fluid flows (11, 12, 13) and to the valve-to-detector conduit (30) via the downstream valve (20).

7. The LC method according to claim 6, comprising connecting the wash selection valve (70) to the fluid stream (11, 12, 13) via a corresponding three-way valve (16, 17, 18) fluidly connected to the downstream valve (20), the three-way valve (16, 17, 18) comprising a wash selection valve inlet port, a downstream valve outlet port and a waste outlet port.

8. LC method according to claim 7, comprising automatically backflushing the at least one HPLC column at regular intervals and / or upon detecting a pressure rise in the fluid stream (11, 12, 13) above a predetermined threshold and / or upon detecting a decrease in the performance of the at least one HPLC column below a predetermined threshold.

9. The LC method according to claim 7 or 8, comprising automatically managing the fluid flow-to-detector connection time, i.e., the connection time between the fluid flow (11, 12, 13) and the valve-to-detector conduit (30), the downstream pump-to-detector connection time, i.e., the connection time between the downstream pump (40) and the valve-to-detector conduit (30), and the downstream pump-to-fluid flow connection time, i.e., the connection time between the fluid flow (11, 12, 13) and the downstream pump (40) by controlling the switch of any one or more of the downstream valve (20), the wash selection valve (70), and the three-way valve (16, 17, 18) by the controller (90).

10. LC method according to claim 6, comprising automatically backflushing the at least one HPLC column at regular intervals and / or upon detecting a pressure rise in the fluid stream (11, 12, 13) above a predetermined threshold and / or upon detecting a performance drop of the at least one HPLC column below a predetermined threshold.

Images