The present disclosure describes a differential refractometer for gradient chromatography. In an exemplary embodiment, the differential refractometer includes a solvent delay volume, an eluent flow meter coupled to an eluent inlet of a sample cell, a solvent flow regulator coupled to an outlet of the solvent delay volume and coupled to a solvent inlet of a reference cell, an instrument controller configured to receive the eluent flow rate from the eluent flow meter, configured to receive the solvent flow rate from the solvent flow regulator, configured to receive a flow rate ratio from a flow rate ratio data source, wherein the flow rate ratio indicates a ratio of the eluent flow rate to the solvent flow rate, and an optical bench configured to measure a difference between a refractive index of the eluent present in the sample cell and a refractive index of the solvent present in the reference cell.

An LC system includes a liquid delivery checker configured to execute a liquid delivery check mode of setting a predetermined flow rate to a liquid delivery pump and operating the liquid delivery pump at a timing different from analysis of a sample in order to check a liquid delivery flow rate of the liquid delivery pump, and a measuring instrument for measuring an amount of a mobile phase delivered by the liquid delivery pump during the liquid delivery check mode. The liquid delivery checker is configured to obtain an actual measurement value of a flow rate of a mobile phase when operating the liquid delivery pump by setting the predetermined flow rate to the liquid delivery pump using a measurement value obtained by the measuring instrument in the liquid delivery check mode.

A sample management device which comprises a source flow path in which a fluidic sample can flow, a volume flow adjustment unit configured to adjust a volume flow of the fluidic sample to be branched off from the source flow path at a fluidic coupling point, and a fluidic valve fluidically coupled with the source flow path and with the volume flow adjustment unit, wherein the fluidic valve is switchable into a branch off state in which the fluidic coupling point is established within the source flow path to branch off an adjustable volume of the fluidic sample from the source flow path via the fluidic coupling point while a flow of the fluidic sample in the source flow path continues.

A liquid chromatography monitoring system comprises a computer or electronic controller comprising computer-readable instructions operable to: (a) draw a fluid into a syringe pump; (b) configure a valve so as to fluidically couple the pump to either a fluidic pathway through a fluidic system or to a plug that prevents fluid flow; (c) cause the syringe pump to progressively compress the fluid therein or expel the fluid to the fluidic pathway, while measuring a pressure of the fluid; (d) determine a profile of the variation of the measured pressure; (e) compare the determined profile to an expected profile that depends upon the fluid; and (f) provide a notification of a sub-optimal operating condition or malfunction if the determined profile varies from the expected profile by greater than a predetermined tolerance.

An injection valve switches between a first state in which a sample loop is connected to a separation flow path through which a mobile phase from a liquid sender flows and a second state in which the sample loop is disconnected from the separation flow path. A pump speed determiner, in a case where a sample intake operation by a syringe pump is started immediately after the injection valve is switched from the second state to the first state, and a filling operation of filling the sample loop with the sample by the syringe pump is started after the intake operation is completed, determines an intake operation speed of the syringe pump that is required in order for the filling operation to complete immediately before the injection valve is switched from the second state to the first state next time using a set injection interval time. The syringe pump operates at the intake operation speed determined by the pump speed determiner while performing the intake operation. The sample is injected by the injector at intervals of the set injection interval time.

A liquid chromatography solvent pump includes at least one motor, a first piston, a second piston, and a continuously variable output drive system coupling the at least one motor to at least one of the first and second pistons. The first piston and the second piston are configured to deliver a flow of solvent in a liquid chromatography system.

A sensor structure is disclosed comprising at least four planar layers subsuming at least one cavity housed but not contained by overlapping apertures through at least two of the planar layers, wherein the at least one cavity comprises a plurality of chambers, and wherein at least one chamber of the plurality of chambers is configured to be in fluid coupling with at least one other chamber. The plurality of chambers may be defined by overlapping apertures through a plurality of the planar layers. The plurality of chambers may include a Gas Chromatograph (GC) column. The planar layers may be flexible flat glass. The planar layers may be fused together. The layers may be made with apertures through the layers disposed in a desired pattern to define complex structures by the apertures overlapping between abutting layers when the layers are stacked. The planar layers may be configured to admit ultraviolet light.

The disclosure relates to a gradient twin column recycling chromatography method that is used to separate a mixture containing closely eluting compounds. In one embodiment, a sample includes a primary organic compound and one or more impurities that closely elute with the primary organic compound. A gradient mobile phase is initially used to remove unwanted early eluting and late eluting impurities from the sample. After the gradient removal of some of the impurities is complete, the remaining mixture of the primary organic compound and the closely eluting impurities are separated using recycle chromatography methodology with an isocratic mobile phase.

There is provided a mass spectrometer that can appropriately maintain the atmospheric pressure of a vacuum chamber, and a method of controlling the same. An example of a mass spectrometer according to the present invention includes first vacuum chambers, first vacuum pumps, an atmospheric pressure relating value acquiring unit, and an adjustment unit configured to adjust the effective exhaust velocity of the first vacuum pumps, and controllers. The controllers control the adjustment unit corresponding to an atmospheric pressure relating value.

A liquid chromatographic (LC) system and a method of exchanging a liquid in an LC system are disclosed. The LC system includes an LC pump with at least one pump head having a primary and a secondary pump head, each with a syringe-like cylinder body having an inner wall surface and a plunger translatable through the cylinder body leaving an interspace between the inner wall surface and the plunger when the plunger is translated through the cylinder body, an upstream inlet valve configured to allow liquid into the cylinder body and a downstream outlet valve configured to allow liquid out of the cylinder body. The LC system further includes at least one liquid-exchange pump connected either to the upstream inlet valve of the primary pump head or to the downstream outlet valve of the secondary pump head.