Abstract: A method for measuring a flow of a fluid in a tube includes heating the fluid in the tube with a heating element. A first signal is measured with a first temperature sensing element at a first location. A second signal is measured with a second temperature sensing element at a second location. At least one temperature signal is calculated based on the first signal and the second signal. The at least one temperature signal includes a difference temperature signal and a sum temperature signal. The difference temperature signal is calculated based on a difference between the second signal and the first signal. The sum temperature signal is calculated based on a sum of the second signal and the first signal. The flow is derived based on the difference temperature signal, the sum temperature signal, or a combination thereof.

Abstract: A method performed in a liquid chromatography system that includes a metering device pushing a sample into a trap column. The metering device sucks in the sample from a sample reservoir, wherein the sucking in the sample from a sample reservoir precedes the step of pushing the sample into the trap column. The liquid chromatography system also includes a trap column and a metering device (100), wherein the system (1000) is adapted to assume a configuration allowing the metering device (100) to push a sample into the trap column (6) and wherein the metering device (100) is adapted to push the sample into the trap column (6) in this configuration, wherein the system (1000) is adapted to assume a configuration allowing the sample to be sucked into the system (1000) by means of the metering device (100). Furthermore, the invention relates to a use of the liquid chromatography system (1000) for liquid chromatography, in particular of high pressure liquid chromatography.

Abstract: The present invention relates to a method comprising using an acoustic wave in a chromatography system. The present invention also relates to a corresponding system and a corresponding use. The system may comprise a surface acoustic wave assembly, wherein the surface acoustic wave assembly comprises a sender unit comprising a sender transducer for sending an acoustic wave and a detection unit for detecting the acoustic wave, a substrate configured for propagation of the acoustic wave, wherein the sender transducer is connected to the substrate, wherein the substrate comprises a substrate section for propagation of the wave from the sender transducer, wherein this substrate section comprises a substrate surface, wherein the surface acoustic wave assembly further comprises at least one channel for conducting fluid, wherein this channel is partly defined by the substrate surface.

Abstract: A control device of a piston pump unit comprising at least two piston-cylinder units that operate in a phase-shifted manner for the purpose of liquid chromatography and to a piston pump unit is described. The control device corrects fluctuations of the system pressure while switching from one piston cylinder unit to the respective other piston cylinder unit. The fluctuations can occur as a result of the cooling of the liquid medium that is heated in an adiabatic manner during a pre-compression phase in the working piston. The control unit controls the piston speed of at least one piston-cylinder unit during the transition phase depending on at least one characteristic, which is ascertained from chronologically previously detected pressure values, such that variations of the system pressure as a result of the cooling of the adiabatically heated medium are at least partially compensated for.

Abstract: A socket unit for a capillary connection system, especially for use in HPLC applications, includes a housing with a housing outer surface and a housing inner surface that define a housing axial cavity. The socket unit also includes a socket connecting mechanism adapted to engage with a corresponding plug connecting mechanism of a plug unit to connect the plug unit and the socket unit together, wherein the socket connecting mechanism is adapted for a predetermined number of discrete connection states between the socket unit and the plug unit.

Abstract: A method of introducing a sample into a separation column includes introducing the sample into a trap column, isolating the trap column from ambient atmosphere and pressurizing the trap column to a first pressure while the trap column is isolated from ambient atmosphere, providing a fluid connection between the trap column and the separation column after pressurizing the trap column to the first pressure, supplying the sample from the trap column to the separation column.

Abstract: The present invention relates to a method of operating a pump generating a flow of a fluid with a pressure, the method comprising operating the pump with a pump speed S satisfying the equation S=Ssimple(1+COR(t)); wherein S is the pump speed, Ssimple is the pump speed disregarding any compression and/or expansion of the fluid, t is a time, and COR(t) is a time dependent correction function; wherein the time dependent correction function COR(t) is a product of a corrective amplitude Acor and a time-dependent function f(t), i.e., COR(t)=Acor·ƒ(t); and wherein the corrective amplitude Acor is set based on a measure for the flow and a measure for the pressure. The present invention also relates to a corresponding use, a pump, a pump system and an HPLC system.

Abstract: The invention relates to a method for setting a gradient delay volume GDV of a liquid chromatography system for a chromatography run in liquid chromatography, in particular a high-performance liquid chromatography system, in which a desired value GDVtarget of a gradient delay volume of the liquid chromatography system is ascertained or predefined and, if the value GDVtarget deviates from a specific fixed value GDVactual of a liquid chromatography system, this value GDVtarget is set in a range 0??GDV=GDVtarget?GDVactual?Vmax of a volume of a volume adjustment device 5. Furthermore, the invention relates to an automatic sampler for carrying out such a method.

Abstract: A liquid chromatography system includes a separation column, a trap column, and a first switching valve. The first switching valve is adapted to assume a first switching position for bringing a sample into the trap column in a first flow direction. The switching valve is also adapted to assume a second switching position for fluidly connecting the trap column with the separation column and providing a flow from the trap column to the separation column in a second flow direction. The second flow direction is opposite to the first flow direction. The first switching valve is adapted to assume a third switching position for fluidly connecting the trap column, with the separation column and providing a flow from the trap column to the separation column in the first flow direction.

Abstract: A sample pre-compression valve for liquid chromatography applications is described. The valve enables a sample pre-compression while the solvent pump continues to conduct solvent to the chromatography column. Furthermore, the sample pre-compression valve includes an INJECT position, a LOAD position and a PUMP PURGE position, in which all connecting grooves of the valve are flushed with liquid. A use of the sample pre-compression valve is described as part of a sampler for liquid chromatography applications.

Abstract: An adapter housing is described that can be used for high performance liquid chromatography, which can be releasably connected to a socket unit. The adapter housing includes a bore which passes through the adapter housing and a pre-column which can be arranged in the bore to protect the separation column from contaminants and/or to concentrate the fluid to be analyzed. A sealing element seals the adapter housing in relation to the socket unit at the end-face wall of a pilot bore.

Abstract: A sampler for liquid chromatography is described. The sampler includes an injection valve and a sample loop. The injection valve includes one waste port, two sample loop ports, and two high-pressure ports. The sample loop port includes a first loop part and a second loop part. The injection valve can be configured to have LOAD position and INJECT position. The injection valve can also be configured to have one or more additional positions such as a FULL PURGE position, a PUMP PURGE position, and a NEGATIVE PRESSURE position.

Abstract: A plug unit for connecting capillary tubes includes a plug housing that has an axial borehole, a plug capillary tube that projects through the axial borehole, and a sealing element that surrounds the plug capillary tube. The front end of the plug capillary tube is sealed by an elastic and/or plastic deformation of the sealing element against the capillary tube receptacle opening of a bushing unit. A hollow cylindrical pressure piece is provided that surrounds the sealing element in an axial region facing away from the end surface of the plug capillary tube, and the pressure piece has a rearward end side that faces away from the end surface of the plug capillary tube and that can be loaded by the plug housing with an axial pressure force when the plug unit and bushing unit are connected.

Abstract: A sample injection method for liquid chromatography is performed with an injection valve having a waste port, two sample loop ports, and two high-pressure ports. One high-pressure port can be connected to a pump and the other high-pressure port can be connected to a chromatography column. A sample loop is connected to one of the sample loop ports on one end and to a pump volume of a sample conveying device on the other end. A section of the sample loop can be separated to facilitate receiving a sample fluid in the sample loop. A control unit controls the injection valve and the sample conveying device. The sample injector allows a sample to be loaded into the sample loop and then pressurized to an operating pressure prior to injecting the sample into the chromatography column. The sample loop may also be isolated from the operating pressure for facilitating depressurization of the loop.

Abstract: The invention relates to a sampler for providing a sample for high-performance liquid chromatography, in which a volume of liquid to be taken up into a cylinder can be aspirated by means of a first drive and can be compressed to a high pressure level by means of a second drive independent of the first drive or can be decompressed from this level in a controlled manner.

Abstract: The invention relates to a seal for high pressure applications, in which a static and a dynamic sealing portion are separated from each other by a material thin point in such a manner that plastic flowing through the thin point is suppressed even if one of the two sealing portions is acted upon under high pressure as far as elastic compression.

Abstract: The invention relates to a sealing mechanism and to a method which forms the basis for the former and in which a clamping ring which loads a sealing element compensates for an operationally induced change in the volume which is available for the sealing element, as a result of which the sealing action of the sealing element can be maintained reliably even in the case of high operating pressures.

Abstract: A plug unit for connecting capillary tubes includes a plug housing that has an axial borehole, a plug capillary tube that projects through the axial borehole, and a sealing element that surrounds the plug capillary tube. The front end of the plug capillary tube is sealed by an elastic and/or plastic deformation of the sealing element against the capillary tube receptacle opening of a bushing unit. A hollow cylindrical pressure piece is provided that surrounds the sealing element in an axial region facing away from the end surface of the plug capillary tube, and the pressure piece has a rearward end side that faces away from the end surface of the plug capillary tube and that can be loaded by the plug housing with an axial pressure force when the plug unit and bushing unit are connected.

Abstract: A sample injection method for liquid chromatography is performed with an injection valve having a waste port, two sample loop ports, and two high-pressure ports. One high-pressure port can be connected to a pump and the other high-pressure port can be connected to a chromatography column. A sample loop is connected to one of the sample loop ports on one end and to a pump volume of a sample conveying device on the other end. A section of the sample loop can be separated to facilitate receiving a sample fluid in the sample loop. A control unit controls the injection valve and the sample conveying device. The sample injector allows a sample to be loaded into the sample loop and then pressurized to an operating pressure prior to injecting the sample into the chromatography column. The sample loop may also be isolated from the operating pressure for facilitating depressurization of the loop.

Abstract: A connector unit for connecting capillaries, for high-performance liquid chromatography includes a connector capillary, a connector housing, and an annular sealing element. The connector capillary projects through a bore of the connector housing. The annular sealing element is provided on a front end region of the connector capillary and which is composed of a plastically and/or elastically deformable material. The connector capillary has an inner shell composed of a plastically and/or elastically deformable material and an outer shell which engages around the inner shell. The inner shell has a radially outwardly extending front end region which, on its own or together with the annular sealing element can generate a seal between the front end region of the connector capillary and a bushing unit.