Disclosed is a HPLC system including a first dimension column, a second dimension column, a high pressure switching valve installed along the mobile phase flow path with the usual detector. At a predetermined time after injection of a sample into the mobile phase stream, the valve is actuated so that late eluted components, while still in the first dimension column, are back-flushed to waste by the flow of mobile phase while the analytes get separated in the second dimension column. Mixed-mode cation exchange and anion exchange columns are particularly suited for this application.

Disclosed is a HPLC system including a first dimension column, a second dimension column, a high pressure switching valve installed along the mobile phase flow path with the usual detector. At a predetermined time after injection of a sample into the mobile phase stream, the valve is actuated so that late eluted components, while still in the first dimension column, are back-flushed to waste by the flow of mobile phase while the analytes get separated in the second dimension column. Mixed-mode cation exchange and anion exchange columns are particularly suited for this application.

A method and a fluidic network for acquiring and injecting a chromatographic sample into a chromatography system flow include a metering pump module, a sample needle, a needle seal and an injection valve. The metering pump module includes a metering pump and a pressure transducer in serial fluidic communication. When the injection valve is in a first valve state, the injection valve is configured to fluidically terminate ports of the metering pump module. When the injection valve is in a second valve state, the injection valve is configured to fluidically couple a fluidic path that includes the metering pump module and sample needle into the system flow of a chromatography system without resulting in a substantial change in the pressure of the system flow.

A method and a fluidic network for acquiring and injecting a chromatographic sample into a chromatography system flow include a metering pump module, a sample needle, a needle seal and an injection valve. The metering pump module includes a metering pump and a pressure transducer in serial fluidic communication. When the injection valve is in a first valve state, the injection valve is configured to fluidically terminate ports of the metering pump module. When the injection valve is in a second valve state, the injection valve is configured to fluidically couple a fluidic path that includes the metering pump module and sample needle into the system flow of a chromatography system without resulting in a substantial change in the pressure of the system flow.

The present disclosure relates to methodologies, systems, apparatus, and kits for introducing a sample within a chromatography system. A makeup pump is configured to pump a makeup fluid through a first restrictor into the chromatography system upstream of the column and downstream of a mobile phase pump. The first restrictor is located upstream of a column and downstream of makeup pump and a sample fluid pump. Decreasing an output volume of the makeup pump can direct a sample fluid from the sample fluid pump through the first restrictor to the column. Increasing an output volume of the makeup pump can direct the sample fluid to a second restrictor located downstream of the makeup pump and in parallel with the column and the detector.

In an LC system using an ODS column (15) and UV detector (17), a cannabis-derived sample is analyzed by gradient elution using a phosphoric acid aqueous solution and phosphoric-acid-containing methanol. A control unit (3) regulates the openings of solenoid valves in a mixer (12) so that the increase rate of the mixture ratio of the phosphoric-acid-containing methanol in a second part of the analysis period is higher than in a first part. By this operation, ten active ingredients (including Total THC, Total CBD and CBN) contained in cannabis can be satisfactorily separated within an analysis time which is equal to or even shorter than approximately 30 minutes. Each ingredient separated by the column (15) is detected by the UV detector (17). An active ingredient identification processor (22) identifies the ten active ingredients based on the retention times of the peaks on a chromatogram created from the detection signals.

A system for pumping a compressible fluid, a chromatography system comprising the system for pumping a compressible fluid, and a chromatography method using the system for pumping a compressible fluid, the system for pumping a compressible fluid comprising at least two pumps including a first pump and a second pump, respective pump outlet lines of which are brought together in a connection piece and are guided out of this connection piece into a common outlet line, wherein the second pump is controllable by a control unit, wherein the control unit is operatively connected to a flowmeter and the pump output of the second pump is controllable as a function of the flow measurement by the control unit.

Liquid chromatography techniques are disclosed. Specifically, the liquid chromatography technique includes providing a liquid chromatography system having a coated metallic fluid-contacting element, and transporting a fluid to contact the coated metallic fluid-contacting element. Conditions for the transporting of the fluid are selected from the group consisting of the temperature of the fluid being greater than 150° C., pressure urging the fluid being greater than 60 MPa, the fluid having a protein-containing analyte incompatible with one or both of titanium and polyether ether ketone, the fluid having a chelating agent incompatible with the one or both of the titanium or the polyether ether ketone, and combinations thereof

Liquid chromatography techniques are disclosed. Specifically, the liquid chromatography technique includes providing a liquid chromatography system having a coated metallic fluid-contacting element, and transporting a fluid to contact the coated metallic fluid-contacting element. Conditions for the transporting of the fluid are selected from the group consisting of the temperature of the fluid being greater than 150° C., pressure urging the fluid being greater than 60 MPa, the fluid having a protein-containing analyte incompatible with one or both of titanium and polyether ether ketone, the fluid having a chelating agent incompatible with the one or both of the titanium or the polyether ether ketone, and combinations thereof

The invention provides a process of controlling the impurities of clindamycin hydrochloride, comprising a step of purifying said clindamycin hydrochloride by two-phase high performance liquid chromatography, wherein the chromatographic conditions are as follows: the detection wavelength is 200-220 nm; the column temperature is 20-40° C.; the flow rate is 0.8-1 ml/min; Mobile phase A: 0.025 mol/L potassium dihydrogen phosphate solution; Mobile phase B: Acetonitrile; and gradient elution is performed. The method of controlling impurities of the invention can solve the problem of the interference by excipients and the problem of the separation of many impurities at the same time. It also provides an effective method for setting quality standard of impurities in such a formulation.