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 fluidic plug unit for liquid-conducting components, in particular for high-performance liquid chromatography, includes a plug housing that has a plug region with a front plug region and a rear plug region which is adjoined thereto in an axial direction. The plug unit is designed for connection to a bushing unit. In a connected state of the plug unit and bushing unit, an annular space, which is substantially closed on all sides, is formed for a sealing element of the plug unit, the annular space being bounded by an outer wall of the front plug region and an inner wall of the receiving recess of the bushing unit.

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: A method for producing a fluidic connection component for chromatography is described. A connection component includes a main body and at least one insert held in the main body. The main body is prefabricated with an aperture for the at least one insert. The at least one insert is connected to the main body securely and fluidically tightly by a thermal process and by making use of a thermal expansion of the main body and/or of the insert that occurs during the thermal process. The method may include a thermally induced change in volume of the main body and/or of the insert that is retained after completion of the thermal process. The material and the geometry of the main body and of the insert and the thermal process are chosen such that, after completion of the thermal treatment, there is a secure and fluidically tight connection.

Abstract: A plug unit and system for connecting capillary tubes, especially for high-performance liquid chromatography, with a plug capillary tube projecting through a hole of a plug housing, which is detachably connectable to a bushing unit. The plug capillary tube front end projects into a capillary tube receptacle in the bushing unit with its end face essentially aligned opposite a front end of a bushing capillary tube or a bushing capillary tube opening of the bushing unit, the end face of which is butted against. The plug housing applies a force, with its end face facing the plug capillary tube end, directly or indirectly on an annular sealing element surrounding the plug capillary tube in the region of the front end of the plug capillary tube such that the front end of the plug capillary tube is sealed through deformation of the sealing element against the capillary tube receptacle opening.

Abstract: A high-pressure switching valve includes a stator and a rotor. The stator includes a plurality of ports where each port is connected at one end to a port connection and having at another end a predetermined port opening cross section at a stator end face of the stator. The rotor includes a rotor end face and at least one or a plurality of grooves. The rotor can be configured to have a rotary position with respect to the stator where two predetermined port opening cross sections connect to one of the grooves in a pressure-tight manner. The rotor and the stator can be pressed together in a sealing manner at the rotor end face and the stator end face in regions away from the port opening cross sections and the at least one or a plurality of grooves. The rotor and the stator each include a hard material. The rotor can be configured to wobble or tilt with respect to a rotational axis of the rotor.

Abstract: The invention relates to a flow cell for absorption detection, in which a tube through which flow is to pass is held at its opposite ends in a supporting flange in each case and is suspended in a substantially cantilevered manner, the two supporting flanges being connected rigidly to each other in order to avoid stresses accidentally introduced into the tube.

Abstract: The invention relates to a connector unit for connecting capillaries, in particular for high-performance liquid chromatography, wherein a sealing element sealing the capillary protrudes at least partially into the interior of the capillary, while a portion of the sealing element that protrudes axially from the capillary can be subjected to a compressive force that is introduced via the capillary to obtain an axial or radial plastic and/or elastic deformation.

Abstract: A sample-taking unit having a sampling unit and a hold-down device which is movable relative thereto in a parallel manner, said sample-taking unit including a self-holding mechanism which, as a result of a self-locking effect, automatically fixes the hold-down device in a lowered fixing position against an upward movement until the self-locking effect is removed again as a result of the self-holding mechanism being acted upon with a detaching force, preferably as a result of contact between the sampling unit and a clamping element of the self-holding mechanism.

Abstract: The invention relates to a method for feeding a sample into an analysis branch of a liquid chromatography system, in particular a high-performance liquid chromatography system. A solvent or a solvent mixture from at least one solvent branch is supplied as volume flow {dot over (A)} into the analysis branch. At least one sample from at least one sample branch is fed as volume flow ? into the analysis branch within a predetermined time interval. The volume flow {dot over (A)} is reduced to an extent during the predetermined time interval, and a volume flow ? resulting from the sum of the volume flows {dot over (A)} and ? remains substantially constant in the analysis branch. The invention further relates to a sampler for carrying out a method of this kind.

Abstract: A control arrangement for controlling a piston pump unit for liquid chromatography, in particular high-performance liquid chromatography, is described. The piston pump unit has at least two piston-cylinder units which operate cyclically in a phase-offset manner and generate, at an outlet port, a predetermined flow of a liquid medium to be delivered. A system pressure is established at the outlet port, irrespective of an associated fluid load resistance. The control arrangement is configured to record the pressure in the cylinder volume of at least a first of the at least two piston-cylinder units. During a measurement phase of the compression phase of the first piston-cylinder unit or during a measurement phase of the decompression phase of the first piston-cylinder unit, the control arrangement stops the drive device for the first piston-cylinder unit for a predetermined time period and in the process records measurement data which characterize the time profile of the pressure.

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 switching valve is described that has a stator which is arranged in a housing and which has multiple connection ports. The switching valve also has a rotatable rotor which is arranged in the housing and which, in predetermined switching positions defined by associated angular positions, interacts with the stator for the fluidic connection or separation of predetermined connection ports. The rotor is rotatably mounted, and acted on with a predefined pressing force in the direction of the stator, by means of a bearing and pressing device arranged in the housing. The bearing and pressing device has a spring device which exerts a load on the rotor or on an element that is capable of performing a wobbling movement.

Abstract: The invention relates to a positioning means for a flow cell used for optical detection, comprising a base having at least one contact face, the contact face being provided to make contact with the end of the flow cell, wherein the base has at least one reference face, which is to be aligned and/or positioned relative to the flow channel of a flow cell, and wherein the base is designed to receive a connecting piece in such a way that the latter assumes a predefined attitude and alignment relative to the flow channel.

Abstract: The invention relates to a switching valve for liquid chromatography having a stator in which multiple ports are formed. Each port is formed by in each case one duct which is connected at one end to in each case one connection port and which, at the other end, has a predetermined port opening cross section at a stator face surface of the stator. The switching valve includes a rotor which has a rotor face surface which interacts with the stator face surface and in which are formed at least one or more grooves. Depending on the rotational position of the rotor with respect to the stator, in at least one predetermined switching position, the switching valve connects respective predetermined port opening cross sections in a pressure-tight manner. The switching valve further includes a drive device for driving the rotor in rotation, and a device for detecting the rotational position of the rotor, which device generates a signal corresponding to the absolute or relative position of the rotor.

Abstract: A switching valve includes a stator and a rotor. The stator includes multiple connection ports. The rotor having predetermined switching positions and interacts with the stator to form a fluidic connection or a fluidic disconnection of predetermined connection ports. The rotor being mounted rotatably via a bearing and pressing device, where the bearing and pressing device is arranged in the housing and loaded with a predefined pressing force in a direction of the stator. The bearing and pressing device includes a spring unit, being supported against a receiving part mounted to rotate about a rotor axis. The receiving part is coupled rotationally conjointly to the rotor and has a drive region which faces away from the stator and is coupled to an output of a drive device.

Abstract: Methods of volume measurement of a liquid are described. During extraction or feed of the liquid, at least two time points of the altered volume of the liquid is measured. Respective hydrostatic pressures are measured at these time points. The pressure difference is determined and the current volume of the liquid present in the container is determined.

Abstract: A plug unit and system for connecting capillary tubes, especially for high-performance liquid chromatography, with a plug capillary tube projecting through a hole of a plug housing, which is detachably connectable to a bushing unit. The plug capillary tube front end projects into a capillary tube receptacle in the bushing unit with its end face essentially aligned opposite a front end of a bushing capillary tube or a bushing capillary passage opening of the bushing unit, the end face of which is butted against. The plug housing applies a force, with its end face facing the plug capillary tube end, directly or indirectly on an annular sealing element surrounding the plug capillary tube in the region of the front end of the plug capillary tube such that the front end of the plug capillary tube is sealed through deformation of the sealing element against the capillary tube receptacle opening.

Abstract: A switching valve, in particular for controlling a fluid subject to high pressure is described. The switching valve has at least one valve unit, which includes a valve seat element and a switching element guided movably in a guide element, wherein the valve seat element and the switching element interact to provide a switching valve function. The valve seat element and the guide element are provided in a housing. The valve seat element, the guide element and the housing form a through flow channel for the fluid to be controlled. An elastically and/or plastically deformable sealing body is provided in a fully enclosed space between the inner wall of the housing and the outer walls of the valve seat element and of the guide element. The sealing body can be subject to a predetermined pressure to seal off the through flow channel from the housing and subject the valve seat element and the guide element to an inward-directed preload.

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.