Provided is a chiller and system that may be utilized in a supercritical fluid chromatography method, wherein a non-polar solvent may replace a portion or all of a polar solvent for the purpose of separating or extracting desired sample molecules from a combined sample/solvent stream. The system may reduce the amount of polar solvent necessary for chromatographic separation and/or extraction of desired samples. The system may incorporate a supercritical fluid chiller, a supercritical fluid pressure-equalizing vessel and a supercritical fluid cyclonic separator. The supercritical fluid chiller allows for efficient and consistent pumping of liquid-phase gases employing off-the-shelf HPLC pumps. The pressure equalizing vessel allows the use of off-the-shelf HPLC column cartridges. The system may further incorporate the use of one or more disposable cartridges containing silica gel or other suitable medium. The system may also utilize an open loop cooling circuit using fluids with a positive Joule-Thomson coefficient.

The present disclosure relates to CO.sub.2-based chromatography for the efficient and precise separation of Vitamin D metabolites.

Methods and systems for pumping compressible fluids in high pressure applications such as high-pressure liquid chromatography (HPLC) or supercritical fluid chromatography (SFC) applications are disclosed. An improved cooling device for a pump head for use in a supercritical fluid chromatography (SFC) system is described. A system for chilling a pumping system, includes a Peltier cooling element in thermal contact with a pump head, wherein the cooling element chills the pump head and a mobile phase fluid flowstream prior to the mobile phase fluid entering the pump; a fluid-cooled heat exchanger, attached to the Peltier cooling element, which removes heat from the cooling element using a circulating fluid; and a second heat exchanger which cools the circulating fluid.

A supercritical fluid chromatography system is provided with an injection valve subsystem for introducing a sample into a flow of mobile phase fluid. The injection valve subsystem includes an auxiliary valve and an inject valve. The operations of the auxiliary and inject valves are coordinated in such a manner as to reduce sample carry-over and system pressure perturbations occurring during sample injection.

A supercritical fluid chromatography system is provided with an injection valve subsystem for introducing a sample into a flow of mobile phase fluid. The injection valve subsystem includes an auxiliary valve and an inject valve. The operations of the auxiliary and inject valves are coordinated in such a manner as to reduce sample carry-over and system pressure perturbations occurring during sample injection.

A supercritical fluid chromatography system is provided with an injection valve subsystem for introducing a sample into a flow of mobile phase fluid. The injection valve subsystem includes an auxiliary valve and an inject valve. The operations of the auxiliary and inject valves are coordinated in such a manner as to reduce sample carry-over and system pressure perturbations occurring during sample injection.

Exemplary embodiments are directed to vent valves, systems and methods generally involving a valve body that includes a seat retainer, a needle and a seat. The seat includes a bore extending there through and the needle includes a needle stem and a needle head. The seat is disposed inside the seat retainer. The needle stem is disposed inside the bore. The needle is configured to be pulled through the seat to stop flow through the bore. Exemplary embodiments are further directed to a system including a stem return spring mechanism and a solenoid return spring mechanism. A processing device is configured to actuate the solenoid return spring mechanism to permit the stem return spring mechanism to pull the needle through the seat to stop flow through the bore.

A supercritical fluid chromatograph includes a supercritical flow path, a mobile phase supply section for supplying a mobile phase containing liquid carbon dioxide, a sample introduction section, a sample separation section, a detector, and a pressure control valve. A valve post-stage flow path is connected to a fluid outlet of the pressure control valve, and the inside of the valve post-stage flow path is maintained by pressure maintaining means at a pressure by which a mobile phase from the fluid outlet of the pressure control valve is not vaporized.

A supercritical fluid chromatograph includes a supercritical flow path, a mobile phase supply section for supplying a mobile phase containing liquid carbon dioxide, a sample introduction section, a sample separation section, a detector, and a pressure control valve. A valve post-stage flow path is connected to a fluid outlet of the pressure control valve, and the inside of the valve post-stage flow path is maintained by pressure maintaining means at a pressure by which a mobile phase from the fluid outlet of the pressure control valve is not vaporized.

A supercritical fluid chromatograph includes a supercritical flow path, a mobile phase supply section for supplying a mobile phase containing liquid carbon dioxide, a sample introduction section, a sample separation section, a detector, and a pressure control valve. A valve post-stage flow path is connected to a fluid outlet of the pressure control valve, and the inside of the valve post-stage flow path is maintained by pressure maintaining means at a pressure by which a mobile phase from the fluid outlet of the pressure control valve is not vaporized.