57 results about "Liquid-liquid chromatography" patented technology

An ultrahigh-pressure dual on-line solid phase extraction / capillary reverse-phase liquid chromatography (DO-SPE / cRPLC) system is provided. The system comprises: a sample loading valve into which a first solvent and a sample to be analyzed are loaded; a first column valve in flow communication with a first solid-phase extraction column and a first reverse-phase liquid chromatography column; a second column valve in flow communication with a second solid-phase extraction column and a second reverse-phase liquid chromatography column; a column-switching valve for determining whether the sample is transferred to either the first column valve or the second column valve; a solvent selection valve in flow communication with the first and second column valves to supply the first solvent or a mixed solvent of the first solvent and a second solvent to the first and second column valves; a second solvent loading valve, in flow communication with a solvent mixer, into which the first and second solvents are loaded; a supply pump for loading the second solvent into the second solvent loading valve; and a supply pump for loading the first solvent into the sample loading valve, the second solvent loading valve and the solvent selection valve. The system requires minimal time (i.e. dead time) for column equilibration between successive experiments to shorten the total time required for the experiments by a factor of about two. In addition, the system enables rapid sample injection, on-line sample desalting and sample enrichment. Furthermore, the system is highly reproducible in terms of liquid chromatography (LC) retention time and can be operated at a pressure as high as 10,000 psi.

Polymer fibers having a novel cross-sectional geometry are used as stationary phase materials for liquid chromatography separations. Fibers of 20 to 50 micrometer diameters have surface-channel structures extending their entire lengths. Bundles of fibers having this novel cross-sectional geometry are packed in columns. Different polymer compositions permit the “chemical tuning” of the separation process. Channeled fibers composed of polystyrene and polypropylene have been used to separate mixtures of polyaromatic hydrocarbons (PAHs), Pb-containing compounds and fatty acids. Use of channeled fibers allows a wide range of liquid flow rates with very low backing pressures. Applications in HPLC, cap-LC, prep-scale separations, analytical separations, single fiber separations, waste remediation / immobilization, extraction of selected organic molecules / ions from solution, purification of liquid streams (process waste, drinking water, pure solvents), selective extraction of cell matter and bacteria from growth media, and immobilization of cell matter and bacteria are envisioned.

The present invention aims to provide a liquid chromatograph, an analysis system, and a gradient elution method, which are designed to permit a gradient change of eluent with higher precision and also permit a high sensitive detection or analysis. For attaining the object, there are provided: a liquid chromatograph having at least a liquid-feeding means for flowing an eluent E at a predetermined flow rate, a sample-pouring means for pouring a sample Sm into the eluent E, and a separation-column means for separating a solute So contained in the sample Sm into components, comprising an eluent-selecting means for forming branched flow paths having predetermined volumes by dividing a flow path of the eluent E fed from the liquid-feeding means, temporally storing eluents E1, E2, and soon in the branched flow paths, and pouring the sample Sm into the selected eluents E1, E2, and so on, and means for carrying out a gradient elution of a solute So; an analysis system comprising a mass spectrometer connected to the liquid chromatograph, and a gradient-elution method using the liquid chromatograph.

A solvent delivery subsystem for a chromatography device performs relatively low pressure, high flow mixing of solvents to form a gradient and subsequent high pressure, low flow delivery of the gradient to the separation column. The mixing of the gradient is independent and does not interfere with the gradient delivery. To form the gradient, the outputs of an aqueous pump and an organic pump are mixed to fill a storage capillary while a downstream point from the storage capillary is vented to atmosphere. After gradient formation, the vent to atmosphere is closed, the solvent delivery system rises to high pressure, and only the aqueous pump runs for gradient delivery. To maintain integrity of the fluid stream, the solvent delivery system uses feed forward compensation and controls at least one parameter selected from the group consisting of pressure and flow in the conduit means to follow a gradual ramp.

There is provided a method for thermally focusing the elution times of compounds of a liquid chromatography system comprising a pre-column and a separation column as well as to provide a liquid chromatography system, wherein the chromatographic separation of a mixture of substances is optimized.

The invention provides a liquid phase mobility separating device, a control method, and an interface used for liquid chromatography-mass spectrometry. The liquid phase mobility separating device comprises a separation capillary, a syringe pump, a sample introduction needle, a separation electrode, and a grounding electrode; one end of the separation capillary is provided with an electrospray point, and the other end is provided with a buffer injection point; the syringe pump is connected with the buffer injection point; the sample introduction needle is connected with the separation capillaryat a position close to the syringe pump; the separation electrode is connected with the syringe pump, or is connected with the separation capillary at a position close to the syringe pump; the grounding electrode is connected with the separation capillary at a position close to the electrospray point. The liquid phase mobility separating device is capable of realizing component separation of a complex sample system, and improving separation effect.

Embodiments of the present invention feature methods and apparatus for performing chromatographic separations. The invention feature methods and control means in the form of computer programs and software that control the formation of a concentration gradient at two or more total flow rates, with an elution period occurring in a slow flow rate and at least other portions of the gradient occurring during a fast total flow rate.