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 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: 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 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 includes a stator and a rotor. The stator includes multiple connection ports. The rotor has predetermined switching positions and interacts with the stator to form a fluidic connection or a fluidic disconnection of predetermined connection ports. The rotor can be mounted rotatably via a bearing and pressing device loaded with a predefined pressing force in a direction of the stator. The bearing and pressing device includes a compensation element to load the rotor and transmit the pressing force. The compensation element is configured to make an elastic flexural deformation so that the compensation element loads the rotor when the rotor is wobbling with respect to an axis of rotation.

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: A sample injector for liquid chromatography includes 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 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 sample injector for liquid chromatography includes 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 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: 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: A switching valve includes a stator and a rotor. The stator includes multiple connection ports. The rotor has predetermined switching positions and interacts with the stator to form a fluidic connection or a fluidic disconnection of predetermined connection ports. The rotor can be mounted rotatably via a bearing and pressing device loaded with a predefined pressing force in a direction of the stator. The bearing and pressing device includes a compensation element to load the rotor and transmit the pressing force. The compensation element is configured to make an elastic flexural deformation so that the compensation element loads the rotor when the rotor is wobbling with respect to an axis of rotation.

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 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: An autosampler for high-performance liquid chromatography (HPLC) with a high-pressure injection valve (1, 2) having improved life, particularly in high pressure operation. The geometry of the valve components and the connections of the high-pressure injection valve are provided such that the switching processes do not take place in a deleterious direction. The grooves in rotor (2) and/or the port opening cross sections (131, 151) in stator (1) and the rotational direction are selected such that fluid flows from grooves under high pressure in the direction of narrow, substantially pressure-free ports are avoided. This applies in particular to the switching process from INJECT to LOAD, since the sample loop contains a relatively large dead volume of compressed fluid. In addition, the valve can be controlled according to the invention in such a manner that an appropriate time is available for reducing harmful or undesired pressure differences.

Abstract: The invention relates to a plug unit for connecting capillary tubes, especially for high-performance liquid chromatography, with a plug housing that has an axial borehole, with a plug capillary tube that projects through the axial borehole of the plug housing, and with a sealing element that has an annular cross section and that surrounds the plug capillary tube, and 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 the bushing unit, wherein the plug housing is constructed so that it can be connected detachably to a bushing unit, wherein the front end of the plug capillary tube projects into a capillary tube receptacle opening of the bushing unit when the plug unit and bushing unit are connected and with its end surface essentially aligned opposite a front end of a bushing capillary tube or a bushing capillary tube opening of the bushing unit, and the sealing element is loaded directly or indirect

Abstract: The invention relates to a plug unit 3 for connecting capillary tubes, especially for high-performance liquid chromatography, with a plug capillary tube 10 that projects through a hole of a plug housing 20, wherein the plug housing 20 is constructed so that it can be connected detachably to a bushing unit 5, wherein the front end of the plug capillary tube 10 projects into a capillary tube receptacle opening 53 of the bushing unit 5 when the plug unit 3 and bushing unit 5 are connected, and with its end face essentially aligned opposite a front end of a bushing capillary tube 57 or a bushing capillary tube opening 55 of the bushing unit 5 and the end face of which is butted against, and wherein the plug housing 20 applies a force, with its end face facing the end of the plug capillary tube 10, directly or indirectly on an annular sealing element 40 surrounding the plug capillary tube 10 in the region of the front end of the plug capillary tube 10 when the plug unit 3 and bushing unit 5 are connected such that

Abstract: The invention pertains to a sample injector for liquid chromatography, particularly for high performance liquid chromatography, with a controllable injection valve (3) that features at least one waste port (12) for discharging fluid under low pressure, two sample loop ports (13, 16) and two high-pressure ports (14, 15) for supplying and discharging fluid under high pressure, wherein one high-pressure port (15) can be connected to a pump (40) and the other high-pressure port (14) can be connected to a chromatography column (41), with a sample loop (44, 51, 52) that comprises a first sample loop section (51) that is connected to one of the sample loop ports (16) on one end and to a pump volume (V) of a sample conveying device (5) on the other end, as well as a second sample loop section (44, 52) that is connected to the other sample loop port (13) on one end and to the pump volume (V) of the sample conveying device (5) on the other end.

Abstract: The invention concerns a capillary-like connector to conduct liquid, in particular, for liquid chromatography, wherein the connector 50, 55 has changing inside cross sections in shape and/or position in the direction of a main flow direction, and an arrangement for liquid chromatography with at least one such capillary-like connector 50, 55.

Abstract: The invention relates to an autosampler for high-performance liquid chromatography (HPLC) with a high-pressure injection valve (1, 2) that has a considerably improved service life in comparison to the prior art, particularly in operation at very high pressures. This objective is achieved according to the invention by adapting the geometry of the valve components in such a manner and establishing the connections of the high-pressure injection valve in such a manner that the switching processes do not take place in a direction that reduces the service life. The grooves (81, 83, 85; 61, 63, 65; 21, 23, 25) in rotor (2) and/or the port opening cross sections (131, 151) in stator (1) and the rotational direction are selected such that fluid flows from grooves (81, 83, 85; 61, 63, 65; 21, 23, 25) under high pressure in the direction of narrow, substantially pressure-free ports (11, 12, 13, 16) are avoided.