SECONDARY STAGE FLUID SEPARATION DEVICE DETACHABLY CONNECTABLE WITH PRIMARY STAGE FLUID SEPARATION DEVICE

Abstract

A secondary stage sample separation device for separating at least a portion of a fluidic sample includes a fluidic interface configured for forming a detachable fluidic coupling between a primary stage sample separation device and the secondary separation device so that the fluidic sample separated by the primary stage sample separation device is fluidically supplyable to the secondary stage sample separation device via the fluidic interface for further separation, wherein the secondary stage sample separation device is further configured for separating at least a portion of the supplied fluidic sample independent of a flow rate of the fluidic sample supplied from the primary stage sample separation device at the fluidic interface.

Claims

1. A secondary stage sample separation device for separating at least a portion of a fluidic sample, wherein the secondary stage sample separation device comprises: a fluidic interface configured for forming a detachable fluidic coupling between a primary stage sample separation device and the secondary separation device so that the fluidic sample separated by the primary stage sample separation device is fluidically supplyable to the secondary stage sample separation device via the fluidic interface for further separation; wherein the secondary stage sample separation device is further configured for separating at least a portion of the supplied fluidic sample independent of a flow rate of the fluidic sample supplied from the primary stage sample separation device at the fluidic interface.

2. The secondary stage sample separation device according to claim 1, comprising a flow rate adapter configured for performing an adaptation between the flow rate of the fluidic sample supplied by the primary stage sample separation device and a flow rate, in particular a smaller flow rate, according to which the secondary stage sample separation device is configured to operate with.

3. The secondary stage sample separation device according to claim 2, wherein the flow rate adapter is configured for performing the adaptation by splitting the fluidic sample supplied to the secondary stage sample separation device into a first flow path corresponding to the flow rate acceptable by the secondary stage sample separation device and used for further separation of at least a portion of the fluidic sample, and into a second flow path, in particular being drained to waste.

4. The secondary stage sample separation device according to claim 2, wherein the flow rate adapter is configured for performing the adaptation by buffering consecutive portions of the fluidic sample supplied by the primary stage sample separation device into a plurality of buffer volumes, in particular sample loops, and for consecutively forwarding the buffered portions of the fluidic sample in the various buffer volumes for the further separation.

5. The secondary stage sample separation device according to claim 2, wherein the flow rate adapter is configured for performing the adaptation by defining a flow rate to one or a plurality of buffer volumes, in a particular way, so as to park a specific representative portion of the fluidic sample relating to a region of interest in a separation spectrum, in particular in a chromatogram, for consecutively forwarding this buffered portion as the fluidic sample for the further separation.

6. The secondary stage sample separation device according to claim 2, wherein the flow rate adapter is configured for performing the adaptation by guiding at least a portion of the fluidic sample provided by the primary stage sample separation device into a selected one of a plurality of sample separation paths in the secondary stage sample separation device, each of the sample separation paths being operable in accordance with an assigned flow rate, so as to obtain a best match between the flow rate of the primary stage sample separation device with a corresponding flow rate assigned to the selected one of the multiple sample separation paths.

7. The secondary stage sample separation device according to claim 2, wherein the flow rate adapter comprises a modulator valve and a flow rate measurement unit for measuring a flow rate in the secondary stage sample separation device, wherein the modulator valve is controlled to switch in accordance with a measured flow rate so as to consecutively forward a predefined amount of the fluidic sample for further separation with each switch.

8. The secondary stage sample separation device according to claim 1, wherein the fluidic interface is configured for being fluidically coupled to a waste conduit of the primary stage sample separation device.

9. The secondary stage sample separation device according to claim 1, configured as a mobile secondary stage sample separation device, in particular as at least one of the group consisting of a transportable, a physically mobile, a roll-comprising, and a rollable secondary stage sample separation device.

10. The secondary stage sample separation device according to claim 1, comprising a cart, in particular having at least one wheel, by which the secondary stage sample separation device is movable, in particular by rolling, by a user.

11. The secondary stage sample separation device according to claim 1, comprising a processor configured for controlling the further sample separation by the secondary stage sample separation device without controlling operation of the sample separation by the primary stage sample separation device.

12. The secondary stage sample separation device according to claim 11, wherein the processor is configured for synchronizing the secondary stage sample separation device with the primary stage sample separation device based on a predefined reference peak resulting from the sample separation by the primary stage sample separation device.

13. The secondary stage sample separation device according to claim 1, comprising at least one of the following features: the secondary stage sample separation device is configured for receiving data indicative of the sample separation by the primary stage sample separation device and is configured for adapting the further sample separation by the secondary stage sample separation device in accordance with the received data; the secondary stage sample separation device comprises an interface detector at the fluidic interface configured for redetecting the fluidic sample separated by the primary stage sample separation device, in particular prior to the further separation of at least a portion of the fluidic sample by the secondary stage sample separation device; the fluidic interface is configured as one of the group consisting of a snap-fit connector, a fitting piece, in particular a male fitting piece or a female fitting piece, a lever-based connector, a bayonet connector and a screw connector.

14. The secondary stage sample separation device according to claim 1, comprising a modulator valve configured for dividing the fluidic sample supplied by the primary stage sample separation device into a plurality of consecutive fluid packets and for consecutively guiding individual ones of the fluid packets into an analytical path of the secondary stage sample separation device in which at least a part of the fluid packets of the fluidic sample are to be further separated.

15. The secondary stage sample separation device according to claim 14, comprising at least one of the following features: the analytical path comprises an analytical pump for pumping mobile phase to be mixed with the fluid packets and comprises a sample separation unit for further separating the fluidic sample in the mixture; the modulator valve comprises a plurality of buffer volumes, in particular sample loops, each for buffering a corresponding one of the fluid packets; the secondary stage sample separation device comprises a plurality of buffer volumes, in particular sample loops, each for buffering a corresponding one of the fluid packets, wherein the buffer volumes are provided separately from the modulator valve and fluidically coupled to the modulator valve.

16. The secondary stage sample separation device according to claim 1, wherein the secondary stage sample separation device is configured as one of the group consisting of: a chromatography sample separation device, in particular a liquid chromatography sample separation device, a gas chromatography sample separation device or a supercritical fluid chromatography sample separation device; and an electrophoresis sample separation device, in particular a capillary electrophoresis sample separation device.

17. A sample separation system for carrying out a multiple stage separation of a fluidic sample, wherein the sample separation system comprises: a primary stage sample separation device for separating a fluidic sample; a secondary stage sample separation device according to claim 1 detachably fluidically coupleable to the primary stage sample separation device via the fluidic interface and configured for separating at least a portion of the fluidic sample supplied and separated by the primary stage sample separation device.

18. The sample separation system according to claim 17, comprising at least one of the following features: the primary stage sample separation device is static; the secondary stage sample separation device is mobile; the sample separation system further comprises at least one further, in particular static, primary stage sample separation device configured for being alternatively fluidically coupleable to the secondary stage sample separation device via the fluidic interface; the primary stage sample separation device is a multiple stage sample separation device; the primary stage sample separation device is configured as one of the group consisting of a chromatography sample separation device, in particular a liquid chromatography sample separation device, a gas chromatography sample separation device or a supercritical fluid chromatography sample separation device, and an electrophoresis sample separation device, in particular a capillary electrophoresis sample separation device; at least one of the primary stage sample separation device and the secondary stage sample separation device comprises a pump configured for driving a mobile phase and the fluidic sample in the mobile phase; at least one of the primary stage sample separation device and the secondary stage sample separation device comprises a separation unit configured for separating at least a portion of the fluidic sample; at least one of the primary stage sample separation device and the secondary stage sample separation device comprises an injector configured for injecting the fluidic sample into the mobile phase; at least one of the primary stage sample separation device and the secondary stage sample separation device comprises a detector configured to detect separated fractions of at least a portion of the fluidic sample; at least one of the primary stage sample separation device and the secondary stage sample separation device comprises a fractioner unit configured to collect separated fractions of the fluidic sample; at least one of the primary stage sample separation device and the secondary stage sample separation device comprises a processor configured to process data related to the fluid separation; at least one of the primary stage sample separation device and the secondary stage sample separation device comprises a degassing apparatus for degassing mobile phase.

19. A method of carrying out a multiple stage separation of a fluidic sample, wherein the method comprises: fluidically coupling a primary stage sample separation device to a secondary stage sample separation device, in particular a secondary stage sample separation device according to claim 1, by attaching a fluidic interface of the secondary stage sample separation device to a fluid outlet of the primary stage sample separation device; carrying out a primary stage separation of the fluidic sample by the primary stage sample separation device; carrying out a secondary stage separation of at least a portion of the fluidic sample by the secondary stage sample separation device by further separating at least a portion of the separated fluidic sample provided at the fluidic interface; after carrying out the primary stage separation and the secondary stage separation, detaching the fluidic interface from the primary stage sample separation device to thereby fluidically decouple the secondary stage sample separation device from the primary stage sample separation device.

20. The method according to claim 19, further comprising: before the fluidically coupling, moving the secondary stage sample separation device, being configured as a mobile secondary stage sample separation device, towards the primary stage sample separation device, being configured as a static primary stage sample separation device; and after the detaching, moving the mobile secondary stage sample separation device away from the static primary stage sample separation device.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0046] 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 drawings. Features that are substantially or functionally equal or similar will be referred to by the same reference signs.

[0047] FIG. 1 illustrates a two-dimensional sample separation system according to an exemplary embodiment of the invention constituted by a static primary stage sample separation device and a mobile secondary stage sample separation device flexibly and detachably connected to one another mechanically and fluidically at a waste conduit of the primary stage sample separation device via a fluidic interface, and configured for conforming the flow rates between the two stages at the fluidic interface in a self-sufficient way and without the necessity of involving a user.

[0048] FIG. 2 illustrates a three-dimensional view of a mobile secondary stage sample separation device mounted on a cart according to an exemplary embodiment of the invention.

[0049] FIG. 3 illustrates a detailed construction of a secondary stage sample separation device according to an exemplary embodiment of the invention.

[0050] FIG. 4 illustrates a one dimensional separation result (in particular a chromatogram) of a primary stage sample separation device presently operating as a standalone device.

[0051] FIG. 5 illustrates a two-dimensional separation result (in particular a chromatogram) of a sample separation system according to an exemplary embodiment of the invention constituted by the primary stage sample separation device of FIG. 4 and a secondary stage sample separation device according to an exemplary embodiment of the invention detachably connected to the primary stage sample separation device.

[0052] FIG. 6 illustrates a two-dimensional sample separation system according to an exemplary embodiment of the invention constituted by a primary stage sample separation device and a secondary stage sample separation device flexibly and detachably connected to the primary stage sample separation device via a detachable fluidic interface.

[0053] FIG. 7 shows the sample separation system of FIG. 6 in another switching state of a modulator valve thereof.

[0054] FIG. 8 shows a portion of a secondary state sample separation device according to an exemplary embodiment in which a modulator valve is in fluid connection with a buffer valve in fluid connection with a plurality of buffer volumes in each of which a respective fluid packet coming from a primary stage sample separation device can be buffered.

[0055] FIG. 9 shows a portion of a secondary stage sample separation device according to an exemplary embodiment in which a modulator valve cooperates with two buffer valves each cooperating with a plurality of buffer volumes for temporarily storing a respective fluid packet.

[0056] FIG. 10 shows a pump of a secondary stage sample separation device according to an exemplary embodiment which allows to define and adapt a flow rate value of fluid flowing through the secondary stage sample separation device.

[0057] The illustration in the drawing is schematic.

[0058] Before, referring to the drawings, exemplary embodiments will be described in further detail, some basic considerations will be summarized based on which exemplary embodiments of the invention have been developed.

[0059] According to an exemplary embodiment of the invention, a second dimension sample separation device (or secondary stage sample separation device) with an assigned separation unit is provided which is configured to fit perfectly to any existing first dimension sample separation device (or primary stage sample separation device) on-the-fly.

[0060] The optimization of (U)HPLC methods for chromatographic resolution gains importance when samples become increasingly complex (i.e. having plenty of compounds). Yet frequently one would encounter evidence (such as a shoulder or tail on a chromatographic peak) or it is a fear that there might be a hidden component that co-elutes in parallel to a substance of interest. An important application example for such a scenario can be found in the pharmaceutical industry: The impurity profiling workflow seeks for impurities in the active pharmaceutical ingredient (API). Impurities have to be reported down to a level of 0.05% of the API. In this case it may be a huge effort to verify. Possibilities are the re-analysis of the sample using different HPLC column media or for example to use orthogonal separation techniques, like electrophoresis. It can be very helpful if a user has a two-dimensional liquid chromatography (2D-LC) system available. Still one would have to develop and optimize a complete 2D-LC method, dedicated for this actual application or a certain application class. The result can be a dramatic loss in performance and efficiency (increased effort and longer time-to-market) due to a potential loss in analysis speed and required optimization procedures. Especial in the initial learning phase, when a user is still doing method development, a sudden unexpected result may be disturbing (at least distracting). Slightest modifications may disrupt and the effect is gone. Even if a user switches from a one-dimensional separation device to a two-dimensional separation device by using the same type of column media, a user still faces the fact that the resolution may be different and the user may have lost the track.

[0061] In order to overcome the above-mentioned shortcomings, an exemplary embodiment of the invention provides a secondary stage sample separation device that can be easily transported to aid in making the second dimension separation independent of a first (one) dimension method. For instance, an existing 1D-LC setup (as primary stage sample separation device) can be simply extended on-the-fly with a second dimension (i.e. the secondary stage sample separation device) that can be used as extension-analyzer that can automatically resolve additional features.

[0062] A secondary stage sample separation device according to an exemplary embodiment of the invention can include one of the following features:

[0063] a pump operable to ensure a predefinable flow rate the second dimension (see FIG. 10)

[0064] a set of columns (preferably such that show as much as possible orthogonal separation behavior) and mobile phases for scouting (see FIG. 3)

[0065] several sample loops with varying volumes (see FIG. 8 and FIG. 9)

[0066] capability of reading 1D-method or raw data from previous runs to align operation of the 2D extension

[0067] lose trigger cable for start indication, or analog pressure synchronization

[0068] inside T-piece with fluidic valve for flow calibration

[0069] According to an exemplary embodiment of the invention, a method of adding a second dimension separation (by providing a secondary stage sample separation device) to a running conventional system (i.e. the primary stage sample separation device) is provided, without a need to modify any hardware, software, firmware components or programmed methods of the existing system (i.e. of the primary stage sample separation device).

[0070] According to another exemplary embodiment of the invention, a second dimension subsystem (i.e. the secondary stage sample separation device) is provided, which can be attached to the outlet of an existing system (i.e. the primary stage sample separation device) to analyze the effluent in the second dimension. The subsystem can be compact, transportable, capable of being operated independently of the first dimension, whereas its operation may be synchronized (in particular as slave) to the first dimension at certain reference points. The subsystem may bear accessory means providing extended independence (for instance a flow splitter, an active flow splitter, a pump as shown in FIG. 10 which is capable of defining a desired flow rate, an independent system controller, etc.) and extended flexibility (such as a variable modulation loop appliance, a column and mobile phase scouting hardware, etc.).

[0071] In an embodiment, when connected to the outlet of an existing 2D-LC setup (as primary stage sample separation device), then the above described cart (as secondary stage sample separation device) actually forms the third dimension.

[0072] FIG. 1 illustrates a two-dimensional sample separation system 100 according to an exemplary embodiment of the invention.

[0073] The sample separation system 100 is constituted by a spatially static primary stage sample separation device 10 and a movable or mobile secondary stage sample separation device 90. They are flexibly and detachably connected to one another mechanically and fluidically via a waste conduit 58 of the primary stage sample separation device 10 and via a fluidic interface 89 of the secondary stage sample separation device 90. In the shown embodiment, the fluidic interface 89 can be a snap-fit connector. For accomplishing the fluidic and mechanical coupling of the primary stage sample separation device 10 and the secondary stage sample separation device 90 according to FIG. 1, the secondary stage sample separation device 90 can be moved towards the static primary sample separation device 10 and can be fluidically coupled in a detachable manner to the primary stage sample separation device 10 via the fluidic interface 89. The secondary stage sample separation device 90 may be movable by a user by driving the secondary sample separation device 90 using a cart 86. The cart 86 has a support and has wheels, wherein the various fluidic members of the secondary stage sample separation device 90 are mounted on the support and can be moved making use of the wheels of the cart 86. Thus, by coupling the secondary stage sample separation device 90 to the primary stage sample separation device 10, it is possible to temporarily establish two-dimensional sample separation system 100. Since the fluidic interface 89 can be a multipurpose fluidic interface, flexible combination of the secondary stage sample separation device 90 with one of different primary stage sample separation devices 10 is possible. The secondary stage sample separation device 90 is configured as to conform the flow rates between the two stages at the fluidic interface 89 in a self-sufficient way and without the necessity of involving a user.

[0074] The secondary stage sample separation device 90 is configured for further separating fractions of the fluidic sample into sub-fractions, which fractions are provided by the primary stage sample separation device 10 as a result of the initial separation of the fluidic sample. As will be described below in further detail, the sample separation system 100 is configured for carrying out two-dimensional liquid chromatography separation (2D-LC) of a fluidic sample.

[0075] Next, the operation of the primary stage sample separation device 10 will be explained. This operation can be a standalone operation, i.e. the primary stage sample separation device 10 may be operated completely independent of the optionally and flexibly connectable secondary stage sample separation device 90 when a single stage separation is sufficient. In such a standalone one-dimensional separation mode, waste conduit 58 is guided into a waste container 60 in which the separated fluidic sample is accumulated. In an extended two-dimensional separation mode as shown in FIG. 1, the waste conduit 58 is mechanically and fluidically connected to the fluidic interface 89, as indicated schematically by reference numeral 21 in FIG. 1.

[0076] When taken alone, the primary stage sample separation device 10 operates as a one dimensional liquid separation system, as follows: A first pump 20 receives a mobile phase as a whole or as individual components that get mixed together by the first pump 20, from a first solvent supply 25, typically via a first degasser 27, which degases and thus reduces the amount of dissolved gases in the mobile phase. The first pump 20as a mobile phase drivedrives the mobile phase through a first separating unit 30 (such as a chromatographic column) comprising a stationary phase. A first sampling unit 40 can be provided between the first pump 20 and the first separating unit 30 in order to subject or add (often referred to as sample introduction) a sample fluid (also denoted as fluidic sample) into the mobile phase. Switching of a fluidic valve 80 actually triggers the injection. The stationary phase of the first separating unit 30 is configured for separating compounds of the sample liquid. After detection of the separated fluidic sample by a first detector 50, the separated fluidic sample is further transported via waste conduit 58 and is then accumulated in the waste container 60.

[0077] A data processing unit 70, 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 primary stage sample separation device 10 in order to receive information and/or control operation. For example, the data processing unit 70 might control operation of the first pump 20 (for instance setting control parameters) and receive therefrom information regarding the actual working conditions (such as output pressure, flow rate, etc.). The data processing unit 70 might also control operation of the first solvent supply 25 (for instance setting the solvent/s or solvent mixture to be supplied) and/or the first degasser 27 (for instance 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 rate, vacuum level, etc.). The data processing unit 70 might further control operation of the first sampling unit 40 (for instance controlling sample injection or synchronization sample injection with operating conditions of the first pump 20). The first separating unit 30 might also be controlled by the data processing unit 70 (for instance selecting a specific flow path or column, setting operation temperature, etc.), and sendin returninformation (for instance operating conditions) to the data processing unit 70. Accordingly, the first detector 50 might be controlled by the data processing unit 70 (for instance with respect to spectral or wavelength settings, setting time constants, start/stop data acquisition), and send information (for instance about the detected sample compounds) to the data processing unit 70.

[0078] In contrast to the primary stage sample separation device 10, the secondary stage sample separation device 90 is not intended to be operated as a standalone device. In contrast to this, operation of the secondary stage sample separation device 90 in terms of sample separation requires mechanical and fluidic connection between the primary stage sample separation device 10 and the secondary sample separation device 90 via the fluidic interface 89, as shown in FIG. 1. When a user wants to extend the one-dimensional separation capability of the primary stage sample separation device 10, the user may detachably fluidically connect the fluidic interface 89 of the secondary stage sample separation device 90 to waste line 58 of the primary stage sample separation device 10.

[0079] In the coupled state as shown in FIG. 1, fluidic sample separated by the primary stage sample separation device 10 into fractions is fluidically supplied to the secondary stage sample separation device 90 for further separation of the fractions into sub-fractions. Advantageously, as will be described below in further detail, the secondary stage sample separation device 90 is configured for further separating the supplied fluidic sample independent or irrespective of a flow rate value of the fluidic sample supplied from the primary stage sample separation device 10 at the fluidic interface 89. Hence, a flow rate adaptation between the given flow rate of the primary stage sample separation device 10 and the adjustable flow rate taken up in the secondary sample separation device 90 is possible by means of a flow rate adapter 88. The latter is configured for performing an adaptation between the flow rate of the fluidic sample supplied by the primary stage sample separation device 10 and a flow rate according to which the secondary stage sample separation device 90 is configured to operate with.

[0080] As can be taken from FIG. 1, the fluid coming from the primary stage sample separation device 10, after adaptation of the flow rate of the two stages by the flow rate adapter 88, is injected via a modulator valve 98 into an analytic path of the secondary sample separation device 90. Mobile phase is provided by a second solvent supply 82. The provided mobile phase can be degassed in a second degasser 84 and can be pumped by a second pump 92 of the secondary stage. At the modulator valve 98, the mobile phase is mixed with a fluid packet originating from the primary stage sample separation device 10. This fluid packet which may include one or more fractions of the fluidic sample is then further separated by liquid chromatography in a second separation unit 93, in particular a further chromatographic column, into sub-fractions. The separated sub-fractions, which can be desorbed from the second separation unit 93 by applying a mobile phase gradient can be detected in a second detector 95. If not a destructive detector (such as a mass spectrometer), the separated sub-fractions can be guided towards a second waste container 96 (alternatively a fraction collector). A second processor 97 of the secondary stage sample separation device 90 is configured for controlling only the secondary separation and does not cooperate with processor 70 of the primary stage sample separation device 10, so that both stages are controlled by a separate independently operating processor 70, 97 or processing routine.

[0081] FIG. 2 illustrates a three-dimensional view of a mobile secondary stage sample separation device 90 mounted on a cart 86 according to an exemplary embodiment of the invention. The individual fluidic components of the secondary stage sample separation device 90 are mounted on the card 86 as modules. A fluidic and mechanical connection to a primary stage sample separation device 10 (not shown) can be accomplished by a user by simply plugging fluidic interface 89 together with a free or open end of a waste conduit 58. A user interface 200, shown as a display, is provided as well which allows unidirectional or bidirectional communication between a user and the secondary stage sample separation device 90.

[0082] FIG. 3 shows a detailed view of a secondary stage sample separation device 90 according to an exemplary embodiment of the invention.

[0083] Downstream of the fluidic interface 89, the fluidic sample arriving from the primary stage sample separation device 10 (not shown in FIG. 3) can be redetected by an interface detector 308. More specifically, interface detector 308 is configured for redetecting the fluidic sample separated by the primary stage sample separation device 10 prior to the further separation of the fluidic sample by the secondary stage sample separation device 90. Knowledge of the way as to how fractions of the fluidic sample have been separated by the primary stage sample separation device 10 and as to how they arrive at the fluidic interface 89 allows the secondary stage sample separation device 90 to adjust its own operation parameters for the secondary separation synchronized to the primary separation. The interface detector 308 may in particular detect a reference peak expected from the primary stage so as to adapt timing of the secondary stage to a given separation timing of the primary stage.

[0084] At a fluidic T-piece 350 downstream of the interface detector 308, a part of the fluidic sample may be guided via a fluid restrictor 352 towards a waste 360, whereas another part (i.e. the rest) of the fluidic sample is guided towards a modulator valve 304. By configuring the fluid restrictor 352 to have an adjustable fluidic impedance or resistance, the individual amounts propagating towards waste 360 and towards modulator valve 304 can be adjusted in terms of flow rate adjustment between the two stages.

[0085] The modulator valve 304 is switchable under control of the control unit 97 (not shown in FIG. 3) so that, consecutively, individual fluid packets of the fluidic sample arriving from the primary stage and passing the fluidic T-piece 350 towards the modulator valve 304 can be injected into an analytical path of the secondary stage.

[0086] However, the analytical path is, according to FIG. 3, selectable. As can be taken from FIG. 3, one of three partially parallel flow paths 302 between the analytical pump 92 and one of a plurality of separation units 93 (for instance chromatographic columns of different dimensions and/or different separation characteristics) can be selected by correspondingly switching a selection valve 354 (which can be switched under control of the control unit 97). Thus, in dependence of the flow rate of the primary stage and/or in dependence or a required/selected separation characteristic, an appropriate one of the individual flow paths 302, each having a different dimension and therefore supporting a respective other flow rate, can be selected.

[0087] Furthermore, adaptation of the flow rate between the two stages is also possible by switching the modulator valve 304 in such a manner that individual fluid packets originating from the primary stage can be buffered temporarily in one of a plurality of buffer volumes 300, configured as separate sample loops. Moreover, a flow rate measurement unit 306 may be provided for measuring a flow rate in the secondary stage sample separation device 90. The modulator valve 304 may be controlled to switch in accordance with a measured flow rate so as to consecutively forward a predefined amount of the fluidic sample for further separation with each switch. Hence, the flow rate measurement unit 306 may measure the flow rate and may supply measurement data to the processor 97 so as to control the flow rate adaptation. Thus, the fluid packets may be supplied packet-wise for further separation by firstly buffering them in one of the buffer volumes 300, and by an appropriately timed switching of the modulator valve 304 so that a new fluidic packet is only injected into one of the analytical paths when appropriate.

[0088] As can be taken from a detail 380 in FIG. 3, as an alternative to the integration of the individual buffer volumes 300 or sample loops in the modulator valve 304, a plurality of buffer volumes 300 may be also provided separately from the modulator valve 304. It is possible to dimension the accommodation volumes of the buffer volumes 300 identical. It is however also possible to dimension them differently so as to obtain sample loops of varying accommodation volume.

[0089] It can be furthermore taken from FIG. 3 that a further possibility of adapting the flow rates of the two stages to one another is the provision of a schematically illustrated flow rate adaptation pump 370 (for instance of the type shown in FIG. 10) which is operable so that only a desired flow rate is allowed to flow through the fluidic interface of the secondary stage.

[0090] FIG. 4 illustrates a one dimensional detection chromatogram 410 of a primary stage sample separation device 10 presently operating as a standalone device. FIG. 5, in addition to one dimensional chromatograms 410 and zooms thereof, illustrates a two-dimensional detection chromatogram 510 of a sample separation system 100 according to an exemplary embodiment of the invention constituted by the primary stage sample separation device 10 according to FIG. 4 and a secondary stage sample separation device 90 according to an exemplary embodiment of the invention detachably connected to the primary stage sample separation device 10. More specifically, FIG. 4 illustrates a diagram 400 having an abscissa 402 along which a retention time (or a retention volume) is plotted, and having an ordinate 404, along which a detection signal of a chromatographic experiment is plotted. It can be seen that a peak region 420 indeed has several sub-peaks 412, 414, 416, which can be distinguished by a secondary stage separation as shown in FIG. 5, which illustrates the result of the second dimension analysis, compare additional diagram 500.

[0091] FIG. 4 and FIG. 5 in particular illustrate the independence of the second dimension when using a 2D-cart architecture by adding a secondary stage sample separation device 90 to a primary stage sample separation device 10. FIG. 4 illustrates a one dimensional chromatogram 410, specifically the zoom or peak portion 420, (Width, W=0.5 min) showing the co-eluting peaks 412, 414, 416. As can be taken from FIG. 5, the one dimensional setup is extended using a 2D-cart including adaptation pump 370 which defines a flow rate in a flow path, whose flow is set to a predefinable value (for instance 50 L/min) that allows to fill a split portion of the peak portion 420 into a 40 L loop 520 in a quantitative manner without having to lower the flow rate in the first dimension. The flow rate of the first dimension continues to be 480 L/min, which makes the volume of the peak region 420 about 240 L.

[0092] FIG. 6 illustrates a two-dimensional sample separation system 100 according to an exemplary embodiment of the invention constituted by a primary stage sample separation device 10 and a secondary stage sample separation device 90 flexibly and detachably connected to the primary stage sample separation device 10 via a detachable fluidic interface 89. FIG. 7 shows the sample separation system 10 of FIG. 6 in another switching state of a modulator valve 304 thereof.

[0093] As can be taken from FIG. 6 and FIG. 7, the modulator valve 304 has in this case two buffer volumes 300, 301 connected to various ports thereof so that fluid packets originating from the primary stage can be buffered in the buffer volumes 300, 301 before being supplied to the analytical path of the secondary stage, i.e. between second pump 92 and second separation unit 93. In the switching state of the modulator valve 304 according to FIG. 6, the buffer volume 300 on the upper right-hand side is presently filled with new fluidic sample flowing from the first dimension into the second dimension, whereas the other buffer volume 301 on the lower left-hand side is presently in the fluidic path between the second pump 92 and the second separation unit 93, i.e. fluidic sample previously stored in this other buffer volume 301 is presently further separated. In the switching state of the modulator valve 304 according to FIG. 7, the buffer volume 301 on the lower left-hand side is presently filled with new fluidic sample flowing from the first dimension into the second dimension, whereas the buffer volume 300 on the upper right-hand side is presently in the fluidic path between the second pump 92 and the second separation unit 93, i.e. fluidic sample previously stored in this buffer volume 300 is presently further separated.

[0094] FIG. 8 shows a portion of a secondary stage sample separation device 90 according to an exemplary embodiment in which modulator valve 304 is in fluid connection with a buffer valve 800 in fluid connection with a plurality of buffer volumes 301 in each of which a respective fluid packet coming from a primary stage sample separation device 10 can be buffered. FIG. 8 shows the modulator valve 304 with buffer valve 800 which can serve in this case six buffer volumes 301 (see numbers 1 to 6 at the buffer valve 800). The switching state according to FIG. 8 corresponds to the switching state according to FIG. 6. The modulator valve 304 further cooperates with the buffer valve 800, which is in direct fluid connection with the individual buffer volumes 301 so that the fluid packets can be temporarily stored in a respectively free one of the buffer volumes 301 and can be subsequently switched individually and one after the other into the analytical path of the secondary stage.

[0095] FIG. 9 shows a portion of a secondary stage sample separation device 90 according to an exemplary embodiment in which modulator valve 304 cooperates with two buffer valves 800, 900 each cooperating with a plurality of buffer volumes 300, 301 for temporarily storing a respective fluid packet. FIG. 9 hence shows an alternative configuration in which one modulator valve 304 cooperates with two packet parking valves 800, 900. Each of the packet parking valves 800, 900 serves six buffer volumes 300, 301 (see numbers 1 to 6 at the buffer valves 800, 900). Hence, any desired number of buffer volumes 300, 301 can be implemented following the principle of FIG. 8 and FIG. 9, so that basically any adaptation of a larger flow rate of the primary stage as compared to a smaller flow rate of the secondary stage is possible.

[0096] FIG. 10 shows a flow rate adaptation pump 370 of a secondary stage sample separation device 90 according to an exemplary embodiment which allows to adapt to a flow rate value of fluid flowing through the fluidic interface 89 of the secondary stage sample separation device 90 by defining the flow rate passing through T-piece 350 towards modulator valve 304. Details of a possible construction of the flow rate adaptation pump 370 are disclosed in GB 2,490,673, which is hereby incorporated by reference in its entirety (see in particular FIG. 5A to FIG. 5F thereof).

[0097] The flow rate adaptation pump 370 is operable so that only a desired flow rate is allowed to flow through the fluidic interface 89 of the secondary stage. In particular, a flow rate between a fluid inlet 1002 and a fluid outlet 1004 can be adjusted by the flow rate adaptation pump 370 under control of the control unit 97. The fluid with the adjustable flow rate flows via the fluid inlet 1002 through a flow rate adaptation valve 1006 and from there into a working chamber 1008 of a first piston pump 1010. A first piston 1012 reciprocates within the working chamber 1008 under control of the control unit 97. In the present scenario, the fluid flows into the working chamber 1008 with a flow rate which is defined by the motion pattern of the first piston 1012. Thus, the velocity according to which the first piston 1012 moves within the first working chamber 1008 under control of the control unit 97 defines the allowed flow rate at this moment. When the first piston 1012 has moved within the first working chamber 1008 up towards an end position in which it is not capable of receiving any further fluid, the flow rate adaptation valve 1006 is switched by the control unit 97 so that the first working chamber 1008 can be emptied towards the fluid outlet 1004 by an inverse motion of the first piston 1012. New fluid from the fluid inlet 1002 can now be accommodated in a second working chamber 1018 of a second piston pump 1020. In the period in which the fluid has been received in the first working chamber 1008, other fluid which has been previously filled into the second working chamber 1018 of the second piston pump 1020 has been guided towards the fluid outlet 1004 by a controlled motion of a second piston 1022. During the corresponding motion of the second piston 1022, the second working chamber 1018 has been emptied. This procedure can be repeated continuously. Thus, with a coordinated switching of the flow rate adaptation valve 1006 and a corresponding control of the movement of the pistons 1012, 1022, all under control of the control unit 97, the flow rate of the fluid flowing between the fluid inlet 1002 and the fluid outlet 1004 can be precisely defined.

[0098] It should be noted that the term comprising does not exclude other elements or features and the a or an does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.