GB2591435A

GB2591435A - Sample injection in a combined chromatography system

Info

Publication number: GB2591435A
Application number: GB1915819.5A
Authority: GB
Inventors: Hruska Vlastimil; Steflova Jana; Seifried Martin
Original assignee: Agilent Technologies Inc
Current assignee: Agilent Technologies Inc
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2021-08-04
Anticipated expiration: 2039-10-31
Also published as: GB201915819D0; GB2591435B

Abstract

An injector, for a combined chromatography system comprising two separation units (e.g. an analytical column and a preparation column in parallel), has a valve switch with bypass loop 230. The injector 40 may inject a first sample fluid into the first mobile phase of the first separation unit, and inject the second sample fluid into the second mobile phase of the second separation unit. Sample fluids may be buffered in first and second sample loops 210, 220. In a first configuration, switching unit 200 may link the first pump 20 and the first separation unit; with the bypass loop 230 coupling second pump 120 and the second separation unit. In a second configuration, bypass loop 230 can be coupled between first pump 20 and the first separation unit; with the second sample loop 220 coupled between second pump 120 and second separation unit.

Description

SAMPLE INJECTION IN A COMBINED CHROMATOGRAPHY

SYSTEM

BACKGROUND ART

[0001] The present invention relates to sample injection in a combined chromatography system such as a combined analytical and preparative chromatography system.

[0002] For liquid separation in a chromatography system, a mobile phase comprising a sample fluid (e.g. a chemical or biological mixture) with compounds to be separated is driven through a stationary phase (such as a chromatographic column packing), thus separating different compounds of the sample fluid which may then be identified. The term compound, as used herein, shall cover compounds which might comprise one or more different components.

[0003] The mobile phase, for example a solvent, is pumped under high-pressure typically through a chromatographic column containing packing medium (also referred to as packing material or stationary phase). As the sample is carried through the column by the liquid flow, the different compounds, each one having a different affinity to the packing medium, move through the column at different speeds. Those compounds having greater affinity for the stationary phase move more slowly through the column than those having less affinity, and this speed differential results in the compounds being separated from one another as they pass through the column. The stationary phase is subject to a mechanical force generated in particular by a hydraulic pump that pumps the mobile phase usually from an upstream connection of the column to a downstream connection of the column. As a result of flow, depending on the physical properties of the stationary phase and the mobile phase, a relatively high-pressure drop is generated across the column.

[0004] The mobile phase with the separated compounds exits the column and passes through a detector, which registers and/or identifies the molecules, for example by spectrophotometric absorbance measurements. A two-dimensional plot of the detector measurements against elution time or volume, known as a chromatogram, may be made, and from the chromatogram the compounds may be identified. For each compound, the chromatogram displays a separate curve feature also designated as a -1 -"peak".

[0005] In preparative chromatography systems, a liquid as the mobile phase is provided usually at a controlled flow rate (e. g. in the range of 1 mL/min to thousands of mL/min, e.g. in analytical scale preparative LC in the range of 1 -5 mL/min and preparative scale in the range of 4-200 mL/min) and at pressure in the range of tens to hundreds bar, e.g. 20 -600 bar.

[0006] In high performance liquid chromatography (HPLC), a liquid as the mobile phase has to be provided usually at a very controlled flow rate (e. g. in the range of microliters to milliliters per minute) and at high-pressure (typically 20-100 MPa, 200- 1000 bar, and beyond up to currently 200 MPa, 2000 bar) at which compressibility of the liquid becomes noticeable.

[0007] In preparative chromatography systems used for chromatography fluidically separating samples at a larger volume, typically in the range of 0.1 mL to tens of mL, there often is a need for analysing a smaller volume of such sample prior to running the separation of the larger volume (e.g. in the sense of an "analytical scouting run"). For such purpose, an analytical chromatography system may be used for chromatographically separating smaller sample volumes, typically in the range of 10 uL -50 ul. Such analytical chromatography system may be an HPLC system.

[0008] The Agilent Dual Loop Sampler G2258A, by the applicant Agilent Technologies, Inc., provides a sampling unit for a combined analytical and preparative chromatography system allowing to inject sample into the analytical as well as the preparative chromatography system.

DISCLOSURE

[0009] It is an object of the invention to provide an improved sample injection into a combined chromatography system, such as an analytical and preparative (or general dual loop) chromatography system. The object is solved by the independent claim(s). Further embodiments are shown by the dependent claim(s).

[0010] According to an exemplary embodiment of the present invention, an injector for a combined chromatography system is provided comprising a first unit and a second unit. The first unit comprises a first pump (preferably a pumping system) and a first -2 -separation unit (preferably a chromatographic column). The first pump is configured for driving a first mobile phase through the first unit, and the first separation unit is configured for separating compounds of a first sample fluid in the first mobile phase. The second unit comprises a second pump (preferably a pumping system) and a second separation unit (preferably a chromatographic column). The second pump is configured for driving a second mobile phase through the second unit, and the second separation unit is configured for separating compounds of a second sample fluid in the second mobile phase. The second sample fluid may be the same as or different than the first sample fluid, and may be in a different volume scale.

[0011] The injector is configured for injecting the first sample fluid into the first mobile phase as well as for injecting the second sample fluid into the second mobile phase. The injector comprises a first sample loop, a second sample loop, and a bypass loop. The first sample loop is configured for receiving and buffering the first sample fluid and for injecting the buffered first sample fluid into the first mobile phase. The second sample loop is configured for receiving and buffering the second sample fluid and for injecting the buffered second sample fluid into the second mobile phase. A switching unit is fluidically coupled to the first pump, the first separation unit, the first sample loop, the second pump, the second separation unit, the second sample loop, and the bypass loop. The switching unit comprises a first switching configuration, wherein the first sample loop is coupled between the first pump and the first separation unit, and the bypass loop is coupled between the second pump and the second separation unit. The switching unit further comprises a second switching configuration, wherein the bypass loop is coupled between the first pump and the first separation unit, and the second sample loop is coupled between the second pump and the second separation unit. This allows to substantially independently from each other operate the first unit and the second unit. For example, one of the first sample loop and the second sample loop can be operated, e.g. filled with respective sample fluid, while the other is provided for sample injection (while being coupled between the respective pump and respective separation unit).

[0012] In one embodiment, in the first switching configuration, the switching unit is further configured for allowing to introduce second sample fluid into the second sample loop. -3 -

[0013] In one embodiment, in the second switching configuration, the switching unit is further configured for allowing to introduce first sample fluid into the first sample loop.

[0014] In one embodiment, the switching unit is configured to fluidically couple to at least one of a sampling pump and a sample source. In the first switching configuration, the switching unit couples at least one of the sampling pump and the sample source to the second sample loop in order to introduce second sample fluid (from the sample source) into the second sample loop. In the second switching configuration, the switching unit couples at least one of the sampling pump and the sample source to the first sample loop in order to introduce first sample fluid (from the sample source) into the first sample loop.

[0015] In one embodiment, the switching unit comprises a plurality of ports, each configured for fluidically coupling from or to the switching unit. The plurality of ports comprise: a first port for coupling to the first pump, a second port for coupling to one end of the first sample loop, a third port for coupling to the other end of the first sample loop, a fourth port for coupling to the first separation unit, a fifth port for coupling to one end of the bypass loop, a sixth port for coupling to the other end of the bypass loop, a seventh port for coupling to the second pump, an eighth port for coupling to one end of the second sample loop, a ninth port for coupling to the other end of the second sample loop, and a tenth port for coupling to the second separation unit. Preferably, the switching unit further comprises an eleventh ports and a twelfth port, each for coupling to the sampling pump, and a thirteenth port and a fourteenth port, each for coupling to the sample source.

[0016] In one embodiment, the switching unit further comprises a sampling switching unit configured for fluidically coupling the sampling pump to either one of the eleventh port or the twelfth port, and/or for fluidically coupling the sample source to either one of the thirteenth port or the fourteenth port.

[0017] In one embodiment, the switching unit comprises one or more of the following switching configurations: [0018] a third switching configuration for depressurising the first sample loop, wherein the first sample loop is coupled to a source of pressure for decreasing a pressure in the first sample loop to a pressure level between a high-pressure level -4 -present during injecting the first sample into the first mobile phase and a low-pressure level present during receiving the first sample into the first sample loop; [0019] a fourth switching configuration for depressurising the second sample loop, wherein the second sample loop is coupled to a source of pressure for decreasing a pressure in the second sample loop to a pressure level between a high-pressure level present during injecting the second sample into the second mobile phase and a low-pressure level present during receiving the second sample into the second sample loop; [0020] a fifth switching configuration for pressurising the first sample loop, wherein the first sample loop is coupled to a source of pressure for increasing a pressure in the first sample loop to a pressure level between a low-pressure level present during receiving the first sample into the first sample loop a high-pressure level present during injecting the first sample into the first mobile phase; and [0021] a sixth switching configuration for pressurising the second sample loop, wherein the second sample loop is coupled to a source of pressure for increasing a pressure in the second sample loop to a pressure level between a low-pressure level present during receiving the second sample into the second sample loop a high-pressure level present during injecting the second sample into the second mobile phase.

[0022] Preferably, the source of pressure is or comprises one or more of: the first pump, the second pump, the sampling pump, and an external pressure source.

[0023] In one embodiment, the switching unit comprises a rotational valve having a rotor and a stator configured for rotating relatively to each other. The rotational valve (also referred to as rotary valve) is preferably configured having two different positions representing two different switching configurations and may work in cluster with one or more solvent selection valves to achieve plural, preferably four, standard configurations (e.g. mainpass/bypass and analytical/preparative).

[0024] In one embodiment, the first pump and the second pump are embodied by a single pumping unit. Preferably, one or more valves may be used for adequately directing flow of the respective mobile phases. -5 -

[0025] According to another exemplary embodiment of the present invention, a combined chromatography system comprises a first unit comprising a first pump (preferably a pumping system) and a first separation unit (preferably a chromatographic column), the first pump being configured for driving a first mobile phase through the first unit, and the first separation unit being configured for separating compounds of a first sample fluid in the first mobile phase. A second unit comprises a second pump (preferably a pumping system) and a second separation unit (preferably a chromatographic column), the second pump being configured for driving a second mobile phase through the second unit, and the second separation unit being configured for separating compounds of a second sample fluid in the second mobile phase. The system further comprises an injector, according to any of the aforedescribed embodiments, being configured for injecting the first sample fluid into the first mobile phase as well as for injecting the second sample fluid into the second mobile phase.

[0026] The combined chromatography system preferably is a liquid chromatography system with both the first mobile phase and the second mobile phase being a liquid, preferably a solvent or solvent mixture.

[0027] In one embodiment of the injector and/or the combined chromatography system, the first unit is or comprises an analytical unit, and the second unit is or comprises a preparative unit. The first pump is an analytical pump and the first separation unit is an analytical separation unit, the analytical pump being configured for driving an analytical mobile phase through the analytical unit, and the analytical separation unit being configured for separating compounds of an analytical sample fluid in the analytical mobile phase. The second pump is a preparative pump and the second preparative separation unit is a preparative separation unit, the preparative pump being configured for driving a preparative mobile phase through the preparative unit, and the preparative separation unit being configured for separating compounds of a preparative sample fluid in the preparative mobile phase. The injector is configured for injecting the analytical sample fluid into the analytical mobile phase as well as for injecting the preparative sample fluid into the preparative mobile phase. The first sample loop is an analytical sample loop configured for receiving and buffering the analytical sample fluid, and for injecting the buffered analytical sample fluid into the analytical mobile phase. The second sample loop is a preparative sample loop configured for receiving and buffering the preparative sample fluid, and for injecting the buffered preparative sample -6 -fluid into the preparative mobile phase. The switching unit is fluidically coupled to the analytical pump, the analytical separation unit, the analytical sample loop, the preparative pump, the preparative separation unit, the preparative sample loop, and the bypass loop. In the first switching configuration, the analytical sample loop is coupled between the analytical pump and the analytical separation unit, and the bypass loop is coupled between the preparative pump and the preparative separation unit. In the second switching configuration, wherein the bypass loop is coupled between the analytical pump and the analytical separation unit, and the preparative sample loop is coupled between the preparative pump and the preparative separation unit.

[0028] Another exemplary embodiment of the present invention provides a method for sample injection into a combined chromatography system. The combined chromatography system comprises a first pump (preferably a pumping system) and a first separation unit (preferably a chromatographic column), the first pump being configured for driving a first mobile phase through the first unit, and the first separation unit being configured for separating compounds of a first sample fluid in the first mobile phase, and a second pump (preferably a pumping system) and a second separation unit (preferably a chromatographic column), the second pump being configured for driving a second mobile phase through the second unit, and the second separation unit being configured for separating compounds of a second sample fluid in the second mobile phase. The method comprises injecting the first sample fluid into the first mobile phase by coupling a first sample loop, containing the first sample fluid, between the first pump and the first separation unit, and coupling a bypass loop between the second pump and the second separation unit, and injecting the second sample into the second mobile phase coupling the second sample loop, containing the second sample fluid, between the second pump and the second separation unit, and by coupling the bypass loop between the first pump and the first separation unit.

[0029] In one embodiment the method comprises, prior to injecting the first sample fluid, coupling the first sample loop to a sample source, and receiving and buffering the first sample fluid into the first sample loop, and prior to injecting the second sample fluid, coupling the second sample loop to the sample source, and receiving and buffering the second sample fluid into the second sample loop.

[0030] In one embodiment the method comprises one or more of the following: -7 - [0031] after injecting a respective first sample fluid into the first mobile phase and prior to receiving a successive first sample into the first sample loop, depressurising the first sample loop, preferably by decreasing a pressure in the first sample loop to a pressure level between a high-pressure level present during injecting the first sample into the first mobile phase and a low-pressure level present during receiving the first sample into the first sample loop; [0032] after injecting a respective second sample fluid into the second mobile phase and prior to receiving a successive second sample into the second sample loop, depressurising the second sample loop, preferably by decreasing a pressure in the second sample loop to a pressure level between a high-pressure level present during injecting the second sample into the second mobile phase and a low-pressure level present during receiving the second sample into the second sample loop; [0033] after receiving a successive first sample into the first sample loop and prior to injecting a respective first sample fluid into the first mobile phase, pressurising the first sample loop, preferably by increasing a pressure in the first sample loop to a pressure level between a low-pressure level present during receiving the first sample into the first sample loop a high-pressure level present during injecting the first sample into the first mobile phase; [0034] after receiving a successive second sample into the second sample loop and prior to injecting a respective second sample fluid into the second mobile phase, pressurising the second sample loop, preferably by increasing a pressure in the second sample loop to a pressure level between a low-pressure level present during receiving the second sample into the second sample loop a high-pressure level present during injecting the second sample into the second mobile phase.

[0035] Injection of the respective sample fluid into the respective mobile phase can be provided by either one or both of the well-known injector schemes, namely "loop injection" and "feed injection". In the loop injection scheme (also referred to as flow-through injection), as described e.g. in US20160334031A1, the respective sample loop is coupled between the respective pump and the respective separation unit, so that the respective mobile phase is flown through the sample loop. In the feed injection scheme, as described e.g. in US2017343520A1, the respective sample loop is fluidically coupled -8 -to the flow path between the respective pump and the respective separation unit, so that for sample injection a flow through the sample loop (containing the sample fluid to be injected) is combined with the flow of the mobile phase.

[0036] Embodiments of the present invention might be embodied based on most conventionally available HPLC systems, such as the Agilent 1220, 1260 and 1290 Infinity LC Series (provided by the applicant Agilent Technologies).

[0037] One embodiment of an HPLC system comprises a pumping apparatus having a piston for reciprocation in a pump working chamber to compress liquid in the pump working chamber to a high-pressure at which compressibility of the liquid becomes noticeable.

[0038] One embodiment of an HPLC system comprises two pumping apparatuses coupled either in a serial or parallel manner. In the serial manner, as disclosed in EP 309596 Al an outlet of the first pumping apparatus is coupled to an inlet of the second pumping apparatus, and an outlet of the second pumping apparatus provides an outlet of the pump. In the parallel manner, an inlet of the first pumping apparatus is coupled to an inlet of the second pumping apparatus, and an outlet of the first pumping apparatus is coupled to an outlet of the second pumping apparatus, thus providing an outlet of the pump. In either case, a liquid outlet of the first pumping apparatus is phase shifted, preferably essentially by 180 degrees, with respect to a liquid outlet of the second pumping apparatus, so that only one pumping apparatus is supplying into the system while the other is intaking liquid (e.g. from the supply), thus allowing to provide a continuous flow at the output. However, it is clear that also both pumping apparatuses might be operated in parallel (i.e. concurrently), at least during certain transitional phases e.g. to provide a smooth(er) transition of the pumping cycles between the pumping apparatuses. The phase shifting might be varied in order to compensate pulsation in the flow of liquid as resulting from the compressibility of the liquid. It is also known to use three piston pumps having about 120 degrees phase shift. Also other types of pumps are known and operable in conjunction with the present invention.

[0039] The separating device preferably comprises a chromatographic column providing the stationary phase. The column might be a glass, metal, ceramic or a composite material tube (e.g. with a diameter from 50 pm to 50 mm (and even larger) -9 -and a length of 1 cm to 1 m) or a microfluidic column (as disclosed e.g. in EP 1577012 A1 or the Agilent 1200 Series HPLC-Chip/MS System provided by the applicant Agilent Technologies. The individual components are retained by the stationary phase differently and separate from each other while they are propagating at different speeds through the column with the eluent. At the end of the column they elute at least partly separated from each other. During the entire chromatography process the eluent might be also collected in a series of fractions. The stationary phase or adsorbent in column chromatography usually is a solid material. The most common stationary phase for column chromatography is silica gel, followed by alumina. Cellulose powder has often been used in the past. Also possible are ion exchange chromatography, reversed-phase chromatography (RP), affinity chromatography or expanded bed adsorption (EBA). The stationary phases are usually finely ground powders or gels and/or are microporous for an increased surface, which can be especially chemically modified, though in EBA a fluidized bed is used.

[0040] The mobile phase (or eluent) can be either a pure solvent or a mixture of different solvents. It can also contain additives, i.e. be a solution of the said additives in a solvent or a mixture of solvents. It can be chosen e.g. to adjust the retention of the compounds of interest and/or the amount of mobile phase to run the chromatography. The mobile phase can also be chosen so that the different compounds can be separated effectively. The mobile phase might comprise an organic solvent like e.g. methanol or acetonitrile, often diluted with water. For gradient operation water and organic is delivered in separate containers, from which the gradient pump delivers a programmed blend to the system. Other commonly used solvents may be isopropanol, THF, hexane, ethanol and/or any combination therefor any combination of these with aforementioned solvents.

[0041] The sample fluid might comprise any type of process liquid, natural sample like juice, body fluids like plasma or it may be the result of a reaction like from a fermentation broth.

[0042] The fluid is preferably a liquid but may also be or comprise a gas and/or a supercritical fluid (as e.g. used in supercritical fluid chromatography -SFC -as disclosed e.g. in US 4,982,597 A). -10-

[0043] The pressure in the mobile phase might range from 2-200 MPa (20 to 2000 bar), in particular 10-150 MPa (100 to 1500 bar), and more particular 50-120 MPa (500 to 1200 bar).

[0044] The HPLC system might further comprise a detector for detecting separated compounds of the sample fluid, a fractionating unit for outputting separated compounds of the sample fluid, or any combination thereof. Further details of HPLC system are disclosed with respect to the aforementioned Agilent HPLC series, provided by the applicant Agilent Technologies.

[0045] Embodiments of the invention can be partly or entirely embodied or supported by one or more suitable software programs, which can be stored on or otherwise provided by any kind of data carrier, and which might be executed in or by any suitable data processing unit. Software programs or routines can be preferably applied in or by the control unit.

[0046] In the context of this application, the term "fluidic sample" or "sample fluid" may particularly denote any liquid and/or gaseous medium, optionally including also solid particles, which is to be analyzed. Such a fluidic sample may comprise a plurality of fractions of molecules or particles which shall be separated, for instance biomolecules such as proteins. Since separation of a fluidic sample into fractions involves a certain separation criterion (such as mass, volume, chemical properties, etc.) according to which a separation is carried out, each separated fraction may be further separated by another separation criterion (such as mass, volume, chemical properties, etc.), thereby splitting up or separating a separate fraction into a plurality of sub-fractions.

[0047] In the context of this application, the term "fraction" may particularly denote such a group of molecules or particles of a fluidic sample which have a certain property (such as mass, volume, chemical properties, etc.) in common according to which the separation has been carried out. However, molecules or particles relating to one fraction can still have some degree of heterogeneity, i.e. can be further separated in accordance with another separation criterion.

[0048] The term "separation unit" may particularly denote a fluidic member through which a fluidic sample is guided and which is configured so that, upon conducting the -11 -fluidic sample through the separation unit, the fluidic sample or some of its components will be at least partially separated into different groups of molecules or particles (called fractions or sub-fractions, respectively) according to a certain selection criterion. An example for a separation unit is a liquid chromatography column which is capable of selectively retarding different fractions of the fluidic sample.

[0049] In the context of this application, the terms "pump", "fluid drive" or "mobile phase drive" may particularly denote any kind of pump or fluid flow source or supply which is configured for conducting a mobile phase and/or a fluidic sample along a fluidic path. A corresponding fluid supply system may be configured for metering two or more fluids in controlled proportions and for supplying a resultant mixture as a mobile phase. It is possible to provide a plurality of solvent supply lines, each fluidically connected with a respective reservoir containing a respective fluid, a proportioning appliance interposed between the solvent supply lines and the inlet of the fluid drive, the proportioning appliance configured for modulating solvent composition by sequentially coupling selected ones of the solvent supply lines with the inlet of the fluid drive, wherein the fluid drive is configured for taking in fluids from the selected solvent supply lines and for supplying a mixture of the fluids at its outlet. More particularly, one fluid drive can be configured to provide a mobile phase flow which drives or carries the fluidic sample through a respective separation unit, whereas another fluid drive can be configured to provide a further mobile phase flow which drives or carries the fluidic sample or its parts after treatment by respective separation unit, through a further separation unit.

[0050] In the context of this application, the term "buffer" or "buffering" may be understood in the sense of temporarily storing or maintaining a dedicated fluid volume.

BRIEF DESCRIPTION OF DRAWINGS

[0051] Other objects and many of the attendant advantages of embodiments of the present invention will be readily appreciated and become better understood by reference to the following more detailed description of embodiments in connection with the accompanied drawing(s). Features that are substantially or functionally equal or similar will be referred to by the same reference sign(s). The illustration in the drawing is schematically. -12-

[0052] Figure 1 shows a combined analytical and preparative chromatography system 5.

[0053] Figure 2 shows in greater detail an embodiment of the injector 40.

[0054] The present invention is not limited to a combined analytical and preparative chromatography system but may be applied to any kind of combined chromatography system having a common injector, preferably in a "dual-loop" configuration with each chromatography system having a dedicated sample loop for sample injection. For the sake of better understanding, the embodiment of a combined analytical and preparative chromatography system shall be explained in the following.

[0055] Figure 1 shows a combined analytical and preparative chromatography system 5 comprising an analytical unit 10 and a preparative unit 15, in accordance with embodiments of the present invention.

[0056] The analytical unit 10 comprises an analytical pump 20 which receives an analytical mobile phase from an analytical solvent supply 25, typically via an analytical degasser 27 which degases the analytical mobile phase and thus reduces the amount of dissolved gases in it. The analytical pump 20 -as a mobile phase drive -drives the analytical mobile phase through an analytical separation unit 30 (such as a chromatographic column) comprising a respective stationary phase. An injector 40 (also referred to as sample introduction apparatus, sample injector, sample dispatcher, etc.) is provided between the analytical pump 20 and the analytical separation unit 30 in order to subject or add (often referred to as sample introduction) portions of one or more analytical sample fluids into the flow of the analytical mobile phase. The stationary phase of the analytical separation unit 30 is adapted for separating compounds of the analytical sample fluid, e.g. a liquid. An analytical detector 50 is provided for detecting separated compounds of the analytical sample fluid. An analytical fractionating unit 60 can be provided for outputting separated compounds of sample fluid.

[0057] The preparative unit 15 comprises a preparative pump 120 which receives a preparative mobile phase from a preparative solvent supply 125, typically via a 30 preparative degasser 127 which degases the preparative mobile phase and thus reduces the amount of dissolved gases in it. The preparative pump 120 -as a mobile -13-phase drive -drives the preparative mobile phase through a preparative separation unit 130 (such as a chromatographic column) comprising a respective stationary phase. The injector 40 also fluidically couples between the preparative pump 120 and the preparative separation unit 130 in order to subject or add (often referred to as sample introduction) portions of one or more preparative sample fluids into the flow of the preparative mobile phase. The stationary phase of the preparative separation unit 130 is adapted for separating compounds of the preparative sample fluid, e.g. a liquid. A preparative detector 150 is provided for detecting separated compounds of the preparative sample fluid. A preparative fractionating unit 160 can be provided for outputting separated compounds of sample fluid.

[0058] While the mobile phase (of each or both of the analytical mobile phase and the preparative mobile phase) can be comprised of one solvent only, it may also be mixed of plurality of solvents. Such mixing might be a low-pressure mixing and provided upstream of the respective pump 20/120, so that the respective pump 20/120 already receives and pumps the mixed solvents as the respective mobile phase. Alternatively, the pump 20/120 might be comprised of plural individual pumping units, with plural of the pumping units each receiving and pumping a different solvent or mixture, so that the mixing of the respective mobile phase (as received by the respective separation unit 30/130) occurs at high-pressure und downstream of the respective pump 20/120 (or as part thereof). The composition (mixture) of the respective mobile phase may be kept constant over time, the so-called isocratic mode, or varied over time, the so-called gradient mode.

[0059] A data processing unit 170, which can be a conventional PC or workstation, might be coupled (as indicated by the dotted arrows) to one or more of the devices in the analytical unit 10 in order to receive information and/or control operation. For example, the data processing unit 170 might control operation of the respective pumps 20 and 120 (e.g. setting control parameters) and receive therefrom information regarding the actual working conditions (such as output pressure, flow rate, etc. at an outlet of the pump). The data processing unit 170 might also control operation of the respective solvent supplies 25 and 125 (e.g. monitoring the level or amount of the solvent available) and/or the respective degassers 27 and 127 (e.g. setting control parameters such as vacuum level) and might receive therefrom information regarding the actual working conditions (such as solvent composition supplied over time, flow -14-rate, vacuum level, etc.). The data processing unit 170 might further control operation of the injector 40 (e.g. controlling sample introduction or synchronization of the sample introduction with operating conditions of the respective pump 20/120). The respective separation units 30 and 130 might also be controlled by the data processing unit 170 (e.g. selecting a specific flow path or column, setting operation temperature, etc.), and send -in return -information (e.g. operating conditions) to the data processing unit 170. Accordingly, the respective detectors 50 and 150 might be controlled by the data processing unit 170 (e.g. with respect to spectral or wavelength settings, setting time constants, start/stop data acquisition), and send information (e.g. about the detected sample compounds) to the data processing unit 170. The data processing unit 170 might also control operation of the respective fractionating units 60 and 160 (e.g. in conjunction with data received from the respective detector 50/150) and provides data back. Finally the data processing unit might also process the data received from the system or its part and evaluate it in order to represent it in adequate form prepared for further interpretation.

[0060] Figure 2 shows in greater detail an embodiment of the injector 40 shown together with certain representatives features of the combined analytical and preparative chromatography system 5 as far as required for better illustration. The injector 40 is configured for injecting the analytical sample fluid into the analytical mobile phase as well as for injecting the preparative sample fluid into the preparative mobile phase. It is clear that the analytical sample fluid and the preparative sample fluid may be different or the same fluid, the latter e.g. in order to analyse a smaller volume of such sample fluid in the analytical unit 10 prior to running separation of larger volume of the sample fluid in the preparative unit 15.

[0061] The injector 40 comprises a switching units 200, an analytical sample loop 210, a preparative sample loop 220, a bypass loop 230, a sampling switching unit 240, and a sampling pump 250, which are fluidically coupled with each other e.g. by respective fluidic conduits is also explained in more detail in the following.

[0062] The analytical sample loop 210 is configured for receiving and buffering the analytical sample fluid, and for injecting the buffered analytical sample fluid into the analytical mobile phase. Accordingly, the analytical sample loop 210 is preferably selected to accommodate a desired volume of the analytical sample fluid to be injected. -15-

[0063] The preparative sample loop 220 is configured for receiving and buffering the preparative sample fluid, and for injecting the buffered preparative sample fluid into the preparative mobile phase. Accordingly, the preparative sample loop 220 is preferably selected to accommodate a desired volume of the preparative sample fluid to be injected. While the accommodation volume of the preparative sample loop 220 may be the same or similar to the accommodation volume of the analytical sample loop 210, the accommodation volume of the preparative sample loop 220 in preferred embodiments is chosen to be significantly larger than the accommodation volume of the analytical sample loop 210 in order to allow injecting significantly larger volumes of sample fluid into the preparative mobile phase (than what is typically required for injecting into the analytical mobile phase). In an example, the accommodation volume of the analytical sample loop 210 may be selected in the range of 10 uL -50 uL, and the accommodation volume of the preparative sample loop 220 may be selected in the range of 0.1 mL -tens of mL. In one embodiment, the analytical loop volume has an accommodation volume of about 450 uL, but only about 10-50 uL of sample fluid can be injected, "the rest" are typically plugs.

[0064] The bypass loop 230 is configured for either coupling the analytical pump 20 to the analytical separation unit 30, or for coupling the preparative pump 120 to the preparative separation unit 130. The bypass loop 230 may be selected to be a short as possible and having a minimal accommodation volume, e.g. substantially resulting from the actual dimension within the switching unit 200. In other words, the bypass loop 230 may not require an accommodation volume at all, i.e. beyond the technical requirements, because sample buffering may not be required in certain embodiments. In a preferred embodiment, the bypass loop 230 may be shortcut or groove between respective valve ports. However, adequate loops similar to the analytical sample loop 210 and/or the preparative sample loop 220, but preferably with significantly larger accommodation volume, may be applied as well.

[0065] The switching unit 200 is fluidically coupled to the analytical pump 20, the analytical separation unit 30, the analytical sample loop 210, the preparative pump 220, the preparative separation unit 120, the preparative sample loop 130, and the bypass loop 230. In one embodiment, analytical and preparative pumps can be physically embodied by one single pump supporting both analytical and preparative flows. An additional valve may then be added to adequately support flow direction. -16-

[0066] In the embodiment of Figure 2, the switching unit 200 comprises a rotational valve 260 having a rotor and a stator (not shown in greater detail in Figure 2) configured for rotating relatively to each other and allowing to define certain switching configurations, as well known in the art. Figure 2 only schematically illustrates the valve 260 having two different switching configurations. It is clear to the skilled person that other valve embodiments and configurations can be applied accordingly. Also, other valve types than rotational valves can be applied accordingly, such as translatory valves providing a translatory movement typically between a movable member and a stator.

[0067] The exemplary embodiment of the rotational valve 260 shown in Figure 2 is a so-called "2/14-valve" and comprises 2 different switching configurations and 14 ports A-N, each port being configured for fluidically coupling from or to the switching unit 200. More specifically, the analytical pump 20 is coupled to a first port A. One end of the analytical sample loop 210 is coupled to a second port B, while the other end of the analytical loop 210 is coupled to a third port C. A forth port D couples to the analytical separation unit 30. The bypass loop 230 is coupled on one end to a fifth port E and on the other end to a sixth port F. A seventh port G is coupled to the preparative pump 120. The preparative sample loop 220 is coupled on one end to an eighth port H and on the other end to a ninth port I. A tenth port J is coupling to the preparative separation unit 130.

[0068] The rotational valve 260 in the embodiment of Figure 2 further comprises seven grooves 261-267, each groove allowing to fluidically coupled two adjacent ports together. While the ports A-N are preferably part of the stator of the valve 260, the grooves 261-267 are preferably part of the rotor of the valve 260, so that by rotating the rotor (by an angle of 360%14 in either direction), the valve 260 can be operated between two different switching configurations, namely a first and a second switching configurations.

[0069] In the first switching configuration of the valve 260, the analytical sample loop 210 is coupled between the analytical pump 20 and the analytical separation unit 30, 30 and the bypass loop 230 is coupled between the preparative pump 120 and the preparative separation unit 130. In the second switching configuration, the bypass loop 230 is coupled between the analytical pump 20 and the analytical separation unit 30, -17-and the preparative sample loop 220 is coupled between the preparative pump 120 and the preparative separation unit 130.

[0070] In the embodiment of Figure 2, the valve 260 is depicted in the second switching configuration, so that groove 261 is coupling between ports A and F, groove 5 262 is coupling between ports B and K, groove 263 is coupling between ports M and C, ..., and groove 267 is coupling between ports H and G. By rotating On either direction) the valve 260 into the next position, namely the first switching configuration (not shown in Figure 2), the groove 261 will be coupling between ports A and B, the groove 262 will be coupling between the ports K and M, ..., and the groove 267 will be coupling 10 between the ports G and F. [0071] In the first switching configuration, the analytical unit 10 is operating in an injection and/or analysing mode, i.e. the analytical sample buffered in the analytical sample loop 210 will be injected into the analytical mobile phase and transported towards the analytical separation unit 30 for chromatographic separation thereof. At the same time, the preparative sample loop 220 is switched off from the pressure path between the preparative pump 120 and the preparative separation unit 130 in the preparative unit 15, e.g. for loading the preparative sample loop 220 with a preparative sample fluid, as will be explained later.

[0072] Accordingly, in the second switching configuration, the preparative unit 15 is operating in an injection and/or analysing mode, i.e. the preparative sample buffered in the preparative sample loop 220 will be injected into the preparative mobile phase and transported towards the preparative separation unit 130 for chromatographic separation thereof. At the same time, the analytical sample loop 210 is switched off from the pressure path between the analytical pump 20 and the analytical separation unit 30 in the analytical unit 10, e.g. for loading the analytical sample loop 210 with an analytical sample fluid, as will be explained later.

[0073] The sampling switching unit 240 is configured for fluidically communicating between the sampling pump 250, a sample source 270, the analytical sample loop 210, and the preparative sample loop 220, in particular in order to fill a respective one of the 30 sample loops with respective sample fluid. The sample source 270 may be or comprise a needle to aspirate a sample fluid from any kind of source such as a vessel, container, -18-online sampling conduit, et cetera.

[0074] In the embodiment of Figure 2, the sampling switching unit 240 is embodied as translatory valve having six ports P-U and two grooves 241 and 242 allowing to fluidically couple between respective two ports. It goes without saying that other valve configurations and types may be applied accordingly and as readily known to the skilled person.

[0075] In the embodiment of Figure 2, the sampling switching unit 240 is depicted in a switching configuration wherein the sampling pump 250 is coupled to port T (e.g. via an external conduit 278), and port S is coupled (e.g. via an external conduit 280) to an eleventh port K of the valve 260. A twelfth port L (of the valve 260) is coupled (e.g. via an external conduit 282) to port U of the sampling switching unit 240. The sample source 270 is coupled to a port O. Port P is coupled (e.g. via an external conduit 284) to a thirteenth port M (of the valve 260), while a fourteenth port N (of the valve 260) is coupled (e.g. via an external conduit 286) to a port R of the sampling switching unit 240.

[0076] It is clear that other connecting schemes as well is valve configurations can be applied accordingly, e.g. dependent on the respective injection operation principle. In the shown embodiment of Figure 2, a one-directional positioning of the respective sample fluid into the respective sample loop is applied, so that sample fluid is only drawn but not pushed. In an alternative embodiment, the sampling switching unit 240 is not required because the injector 40 comprises two needle-seat configurations providing the selection between respective sample loops. In another embodiment, a different injection principle is applied in that the sample fluid is first drawn into a respective sample loop or other buffer loop inside the injector 40 (which may be shared for both sample loops) and the sample fluid is then pushed through the needle seat (e.g. to a valve and) to the respective sample loop. In such embodiment, the ports M and N can be directly connected to the individual seats, and ports K and L can be provided as waste lines. In general, ports K, L, M, N are preferably applied for selecting the loop mode (e.g. analytical or preparative injection mode) and delivering the sample into the selected sample loop.

[0077] In the second switching configuration as illustrated in Figure 2, the sampling -19-pump 250 is coupled via conduit 278, the groove 242, and the conduit 282 to port L which is coupled via groove 266 to port N, which in turn is coupled to the sample source 270 via the conduit 286, the groove 241, and an external conduit 288. This allows the sampling pump 250 to draw sample from the sample source 270 into one or 5 more of the conduits 288, 286, and 282. The drawn in sample can then be positioned into either one of the analytical sample loop 210 or the preparative sample loop 220, depending on the respective switching configurations of the valve 260 and the sampling switching unit 240. For positioning the drawn in sample into the analytical loop 210, the sampling switching unit 240 is switched into a position wherein groove 242 is coupling 10 between ports S and land groove 241 is coupling between ports 0 and P. [0078] In the first switching configuration (when valve 260 as shown in Figure 2 is moved to the next position), sample can be drawn in from the sample source 270 by switching the sampling switching unit 240 so that groove 242 is coupling between ports T and S, and groove 241 is coupling between ports 0 and P. Thus, the sampling pump 252 is coupled to port K which is coupled via a respective one of the grooves 261-267 to port M, which in turn is coupled to the sample source 270 via the groove 241. This allows the sampling pump 250 to draw sample from the sample source 270 into one or more of the conduits 288, 284, and 280. The drawn in sample can then be positioned into either one of the analytical sample loop 210 or the preparative sample loop 220, depending on the respective switching configurations of the valve 260 and the sampling switching unit 240. For positioned the drawn in sample into the preparative loop 220, the sampling switching unit 240 is switched into the other position wherein groove 242 is coupling between ports U and T and groove 241 is coupling between ports 0 and R. [0079] Alternatively or in addition to the aforedescribed scheme for loading sample fluid from the sample source 270 into a respective one of the analytical sample loop 210 and the preparative sample loop 220, the valve 265 together with the sampling switching unit 240 can be operated so that sample fluid from the sample source 270 is directly drawn into the respective sample loop (i.e. either the analytical sample loop 210 and the preparative sample loop 220), so that no additional push or other positioning movement is required. This may also allow moving the sample fluid not beyond the respective sample loop and/or to avoid overfilling of the respective sample loop (i.e. introducing more sample fluid into the respective sample loop than the actual accommodation volume of such sample loop).

-20 - [0080] It is to be understood that each sample loop (i.e. the analytical sample loop 210 and the preparative sample loop 220) is typically operated between two substantially different pressure levels. A high-pressure level applies when the respective sample loop is coupled between the respective pump and respective separation unit, e.g. during injecting the respective sample into the respective mobile phase. A low-pressure level applies when the respective sample loop is decoupled from the respective pump e.g. for receiving the respective sample. While the high-pressure level may be in the range of several hundred bar (e.g. 600 bar) and currently up to 2000 bar, the low-pressure level may be close to ambient and e.g. in the range of 1-50 bar, preferably about or maximum 2 bar. When switching the sample loop from the high-pressure level to or towards the low-pressure level, any remaining fluid in the sample loop (which is typically fully filled at this time) may expand in volume On particular when the fluid had been compressed under the influence of the high-pressure level). Such volume expansion may provide stress and may even lead to damages to other components in the system 5.

[0081] In order to avoid or reduce damages resulting from switching between the high-pressure level and the low-pressure level, the respective sample loop is preferably depressurised by decreasing pressure in the sample loop to a pressure level between the high-pressure level and the low-pressure level. It goes without saying that the sample loop is preferably depressurised to or close to the low-pressure level in order to minimise potential damages.

[0082] In the same way, the respective sample loop may also be preferably pressurised before being switched between the respective pump and separation unit, e.g. by increasing pressure in the sample loop to a pressure level between the low-pressure level and the high-pressure level. Preferably, the sample loop is compressed to or close to the high-pressure level.

[0083] Pressurising and/or depressurising a respective sample loop can be provided in plural ways, e.g. by using one of the pressure sources already present in the system 5, such as one of the analytical pump 20 or the preparative pump 120, or the sampling pump 250. Alternatively or in addition, an external pressure source (not shown in Figure 2) may also be applied. Pressurising and/or depressurising can be provided by adequately switching the valve 260 and/or the sampling switching unit 240 and -21 -operating the respective pressure source(s).

[0084] In one embodiment, operation of the injector 40 is provided by first depressurising the analytical sample loop 210 when being in the first switching configuration. The analytical pump 20 is operated to ramp down its flow to or close to zero, and the injector 40 waits until pressure drops below a certain limit (e.g. 20 bar).

The valve 260 is then switched into the second switching configuration, so that the analytical pump 20 is coupled directly via the bypass loop 230 to the analytical separation unit 30, and the analytical sample loop 210 is accordingly switched off from between the analytical pump 20 and the analytical separation unit 30. At the same time, the sampling switching unit 240 is switched in order to connect the sampling pump 250 through the analytical sample loop 210 to the sample source 270, thus allowing the sampling pump 250 to draw sample and position it into the analytical sample loop 210. The valve 260 can then be switched back into the first switching configuration to inject the buffered analytical sample in the analytical unit 10. After the analysis, the sampling path may be cleaned (e.g. by use of the sampling pump 250).

[0085] Accordingly, operation of the injector 40 can be provided by first depressurising the preparative sample loop 220 when being in the second switching configuration. The preparative pump 120 is operated to ramp down its flow to or close to zero, and the injector 40 waits until pressure drops below a certain limit (e.g. 10 bar).

The valve 260 is then switched into the first switching configuration, so that the preparative pump 120 is coupled directly via the bypass loop 230 to the preparative separation unit 130, and the preparative sample loop 220 is accordingly switched off from between the preparative pump 120 and the preparative separation unit 130. At the same time, the sampling switching unit 240 is switched in order to connect the sampling pump 250 through the analytical sample loop 210 to the sample source 270, thus allowing the sampling pump 250 to draw sample and position it into the preparative sample loop 220. The valve 260 can then be switched back into the second switching configuration to inject the buffered preparative sample in the preparative unit 15. After the analysis, the sampling path may be cleaned (e.g. by use of the sampling pump 250).

[0086] As the embodiment of Figure 2 is substantially symmetrical or mirrored for the analytical unit 10 and the preparative unit 15, operation thereof may also be -22 -substantially symmetrical or mirrored. For the sake of better understanding, one of the analytical pump 20 and the preparative pump 120 shall be referred to as pump A, while the other pump shall be referred to as pump B. The respective separation unit coupled to or to be coupled to that pump A shall be referred to as separation unit A, and the other separation unit coupled to or to be coupled to that pump B shall be referred to as separation unit B. Accordingly, the respective sample loop (either the analytical sample loop 210 or the preparative sample loop 220) coupled to pump A shall be referred to as sample loop A, while the other sample loop shall be referred to as sample loop B. Using this nomenclature, preferred modes of operation in an embodiment can be described as the following: [0087] (1) Pump A is fluidically coupled to separation unit A through sample loop A, so that sample loop A is pressurized. Pump B is fluidically coupled to separation unit B through bypass loop 230. Sample loop B decoupled from pump B, so that sample loop B is depressurized. Optionally, sample loop B may be coupled to waste for full depressurization (e.g. by switching of sampling switching unit 240).

[0088] (2) Pump A ramps down to depressurize sample loop A. [0089] (3) Switching valve 260 so that pump B is fluidically coupled to separation unit B through sample loop B, so that sample loop B is or will be pressurized. Pump A is fluidically coupled to separation unit A through bypass loop 230. Sample loop A is decoupled from pump A, so that sample loop A is or will be depressurized. Optionally, sample loop A may be coupled to waste for full depressurization (e.g. by switching of sampling switching unit 240).

[0090] Repeat (1)-(3) starting with state (3) and exchanging A with B, or vice versa.

[0091] As apparent from the description above, the switching unit 200 preferably mirrors the connections and functions of the analytical unit 10 and the preparative unit 15. This leads to a clearer coupling scheme. However, it is clear that other connections and functions can be applied accordingly.

[0092] Also, while the valve 260 and the sampling switching unit 240 are shown in the embodiment of Figure 2 as individual valves, it is clear that both may be incorporated into a single valve. Alternatively, more than two valves may be applied to -23 -provide the switching functionality of the valve 260 and/or the sampling switching unit 240 of the embodiment of Figure 2.

[0093] In the aforedescribed embodiment of Figure 2, injection of the respective sample fluid into the respective mobile phase is provided by "loop injection", wherein the respective sample loop is coupled between the respective pump and the respective separation unit, so that the respective mobile phase is flown through the sample loop. In an alternative embodiment, not shown in Figure 2, a feed injection scheme, as described e.g. in US2017343520A1, wherein the respective sample loop is fluidically coupled to the flow path between the respective pump and the respective separation unit, so that for sample injection a flow through the sample loop (containing the sample fluid to be injected) is combined with the flow of the mobile phase. In a further embodiment, both injection schemes, namely loop injection and feed injection, can be applied alternatively.

-24 -

Claims

CLAIMS1. An injector (40) for a combined chromatography system (5) comprising a first unit (10) and a second unit (15), wherein the first unit (10) comprises a first pump (20) and a first separation unit (30), the first pump (20) being configured for driving a first mobile phase through the first unit (10), and the first separation unit (30) being configured for separating compounds of a first sample fluid in the first mobile phase, and the second unit (15) comprises a second pump (120) and a second separation unit (130), the second pump (120) being configured for driving a second mobile phase through the second unit (15), and the second separation unit (130) being configured for separating compounds of a second sample fluid in the second mobile phase, the injector (40) being configured for injecting the first sample fluid into the first mobile phase as well as for injecting the second sample fluid into the second mobile phase, and comprising: a first sample loop (210) configured for receiving and buffering the first sample fluid, and for injecting the buffered first sample fluid into the first mobile phase, a second sample loop (220) configured for receiving and buffering the second sample fluid, and for injecting the buffered second sample fluid into the second mobile phase, a bypass loop (230), and a switching unit (200) being fluidically coupled to the first pump (20), the first separation unit (30), the first sample loop (210), the second pump (120), the second separation unit (130), the second sample loop (220), and the bypass loop (230), wherein the switching unit (200) comprises a first switching configuration, wherein the first sample loop (210) is coupled between the first pump (20) and the first separation unit (30), and the bypass loop -25 - (230) is coupled between the second pump (120) and the second separation unit (130), and a second switching configuration, wherein the bypass loop (230) is coupled between the first pump (20) and the first separation unit (30), and the second sample loop (220) is coupled between the second pump (120) and the second separation unit (130).
2. The injector (40) of claim 1 or any of the above claims, wherein in the first switching configuration, the switching unit (200) is further configured for allowing to introduce second sample fluid into the second sample loop (220).
3. The injector (40) of claim 1 or any of the above claims, wherein in the second switching configuration, the switching unit (200) is further configured for allowing to introduce first sample fluid into the first sample loop (210).
4. The injector (40) of claim 1 or any of the above claims, wherein: the switching unit (200) is configured to fluidically couple to at least one of a sampling pump (250) and a sample source (270), wherein in the first switching configuration, the switching unit (200) couples at least one of the sampling pump (250) and the sample source (270) to the second sample loop (220) in order to introduce second sample fluid into the second sample loop (220), and in the second switching configuration, the switching unit (200) couples at least one of the sampling pump (250) and the sample source (270) to the first sample loop (210) in order to introduce first sample fluid into the first sample loop (210).
5. The injector (40) of claim 1 or any of the above claims, wherein: the switching unit (200) comprises a plurality of ports, each configured for fluidically coupling from or to the switching unit (200), wherein the plurality of ports comprise: a first port for coupling to the first pump (20), -26 -a second port for coupling to one end of the first sample loop (210), a third port for coupling to the other end of the first sample loop (210), a forth port for coupling to the first separation unit (30), a fifth port for coupling to one end of the bypass loop (230), a sixth port for coupling to the other end of the bypass loop (230), a seventh port for coupling to the second pump (120), an eighth port for coupling to one end of the second sample loop (220), a ninth port for coupling to the other end of the second sample loop (220), and a tenth port for coupling to the second separation unit (130).
6. The injector (40) of the preceding claim as far as referred to claim 5, the switching unit (200) further comprising: an eleventh port and a twelfth port, each for coupling to the sampling pump (250), and a thirteenth port and a fourteenth port, each for coupling to the sample source (270).
7. The injector (40) of the preceding claim, the switching unit (200) further comprising: a sampling switching unit (200) configured for fluidically coupling the sampling pump (250) to either one of the eleventh port or the twelfth port, and/or for fluidically coupling the sample source (270) to either one of the thirteenth port or the fourteenth port.
8. The injector (40) of claim 1 or any of the above claims, wherein the switching unit (200) comprises at least one of: a third switching configuration for depressurising the first sample loop (210), wherein the first sample loop (210) is coupled to a source of pressure for -27 -decreasing a pressure in the first sample loop (210) to a pressure level between a high-pressure level present during injecting the first sample into the first mobile phase and a low-pressure level present during receiving the first sample into the first sample loop (210); a fourth switching configuration for depressurising the second sample loop (220), wherein the second sample loop (220) is coupled to a source of pressure for decreasing a pressure in the second sample loop (220) to a pressure level between a high-pressure level present during injecting the second sample into the second mobile phase and a low-pressure level present during receiving the second sample into the second sample loop (220); a fifth switching configuration for pressurising the first sample loop (210), wherein the first sample loop (210) is coupled to a source of pressure for increasing a pressure in the first sample loop (210) to a pressure level between a low-pressure level present during receiving the first sample into the first sample loop (210) a high-pressure level present during injecting the first sample into the first mobile phase; a sixth switching configuration for pressurising the second sample loop (220), wherein the second sample loop (220) is coupled to a source of pressure for increasing a pressure in the second sample loop (220) to a pressure level between a low-pressure level present during receiving the second sample into the second sample loop (220) a high-pressure level present during injecting the second sample into the second mobile phase.
9. The injector (40) of the preceding claim, wherein the source of pressure is or comprises one or more of: the first pump (20), the second pump (120), the sampling pump (250), and an external pressure source.
10. The injector (40) of claim 1 or any of the above claims, comprising at least one of: the switching unit (200) comprises a rotational valve having a rotor and a stator configured for rotating relatively to each other; the first pump (20) and the second pump (120) are embodied by a single pumping unit.
-28 - 11. A combined chromatography system (5), comprising: a first unit (10) comprising a first pump (20) and a first separation unit (30), the first pump (20) being configured for driving a first mobile phase through the first unit (10), and the first separation unit (30) being configured for separating compounds of a first sample fluid in the first mobile phase, a second unit (15) comprising a second pump (120) and a second separation unit (130), the second pump (120) being configured for driving a second mobile phase through the second unit (15), and the second separation unit (130) being configured for separating compounds of a second sample fluid in the second mobile phase, and an injector (40), according to any of the above claims, being configured for injecting the first sample fluid into the first mobile phase as well as for injecting the second sample fluid into the second mobile phase.
12. The injector (40) and/or the combined chromatography system (5) according to any one of the above claims, wherein the combined chromatography system (5) is a liquid chromatography system with both the first mobile phase and the second mobile phase being a liquid, preferably a solvent or solvent mixture.
13. The injector (40) and/or the combined chromatography system (5) according to any one of the above claims, wherein the first unit (10) is or comprises an analytical unit (10) and the second unit (15) is or comprises a preparative unit (15), wherein the first pump (20) is an analytical pump (20) and the first separation unit (30) is an analytical separation unit (30), the analytical pump (20) being configured for driving an analytical mobile phase through the analytical unit (10), and the analytical separation unit (30) being configured for separating compounds of an analytical sample fluid in the analytical mobile phase, and the second pump (120) is a preparative pump (120) and the second preparative separation unit (130) is a preparative separation unit (130), the preparative pump (120) being configured for driving a preparative mobile phase through the preparative unit (15), and the preparative separation unit (130) being configured -29 -for separating compounds of a preparative sample fluid in the preparative mobile phase, the injector (40) is configured for injecting the analytical sample fluid into the analytical mobile phase as well as for injecting the preparative sample fluid into the preparative mobile phase, the first sample loop (210) is an analytical sample loop (210) configured for receiving and buffering the analytical sample fluid, and for injecting the buffered analytical sample fluid into the analytical mobile phase, the second sample loop (220) is a preparative sample loop (220) configured for receiving and buffering the preparative sample fluid, and for injecting the buffered preparative sample fluid into the preparative mobile phase, the switching unit (200) is fluidically coupled to the analytical pump (20), the analytical separation unit (30), the analytical sample loop (210), the preparative pump (120), the preparative separation unit (130), the preparative sample loop (220), and the bypass loop (230), in the first switching configuration, the analytical sample loop (210) is coupled between the analytical pump (20) and the analytical separation unit (30), and the bypass loop (230) is coupled between the preparative pump (120) and the preparative separation unit (130), and in the second switching configuration, wherein the bypass loop (230) is coupled between the analytical pump (20) and the analytical separation unit (30), and the preparative sample loop (220) is coupled between the preparative pump (120) and the preparative separation unit (130).
14. A method for sample injection into a combined chromatography system (5) comprising: a first pump (20) and a first separation unit (30), the first pump (20) being configured for driving a first mobile phase through the first unit (10), and the first separation unit (30) being configured for separating compounds of a first sample fluid in the first mobile phase, and -30 -a second pump (120) and a second separation unit (130), the second pump (120) being configured for driving a second mobile phase through the second unit (15), and the second separation unit (130) being configured for separating compounds of a second sample fluid in the second mobile phase, the method comprising: injecting the first sample fluid into the first mobile phase by coupling a first sample loop (210), containing the first sample fluid, between the first pump (20) and the first separation unit (30), and coupling a bypass loop (230) between the second pump (120) and the second separation unit (130), and injecting the second sample into the second mobile phase coupling the second sample loop (220), containing the second sample fluid, between the second pump (120) and the second separation unit (130), and by coupling the bypass loop (230) between the first pump (20) and the first separation unit (30).
15. The method of the preceding method claim, further comprising: prior to injecting the first sample fluid, coupling the first sample loop (210) to a sample source (270), and receiving and buffering the first sample fluid into the first sample loop (210), and prior to injecting the second sample fluid, coupling the second sample loop (220) to the sample source (270), and receiving and buffering the second sample fluid into the second sample loop (220).
16. The method of the preceding method claim, further comprising at least one of: after injecting a respective first sample fluid into the first mobile phase and prior to receiving a successive first sample into the first sample loop (210), depressurising the first sample loop (210), preferably by decreasing a pressure in the first sample loop (210) to a pressure level between a high-pressure level present during injecting the first sample into the first mobile phase and a low-pressure level present during receiving the first sample into the first sample loop (210); after injecting a respective second sample fluid into the second mobile phase and prior to receiving a successive second sample into the second sample loop (220), -31 -depressurising the second sample loop (220), preferably by decreasing a pressure in the second sample loop (220) to a pressure level between a high-pressure level present during injecting the second sample into the second mobile phase and a low-pressure level present during receiving the second sample into the second sample loop (220); after receiving a successive first sample into the first sample loop (210) and prior to injecting a respective first sample fluid into the first mobile phase, pressurising the first sample loop (210), preferably by increasing a pressure in the first sample loop (210) to a pressure level between a low-pressure level present during receiving the first sample into the first sample loop (210) a high-pressure level present during injecting the first sample into the first mobile phase; after receiving a successive second sample into the second sample loop (220) and prior to injecting a respective second sample fluid into the second mobile phase, pressurising the second sample loop (220), preferably by increasing a pressure in the second sample loop (220) to a pressure level between a low-pressure level present during receiving the second sample into the second sample loop (220) a high-pressure level present during injecting the second sample into the second mobile phase.
17. A software program or product, preferably stored on a data carrier, for controlling or executing the method of any of the above method claims, when run on a data processing system such as a computer.-32 -