摘要:
A method for controlling pervaporation through a membrane includes assessing the vapor pressure of each component material of a mobile phase disposed on a retentate side of the membrane, and maintaining a designed environment on a permeate side of the membrane. The environment maintained on the permeate side of the membrane contains partial pressures of selected component materials of the mobile phase at a level substantially equal to or greater than the respective vapor pressures thereof.
摘要:
An example of a gas detection system includes a gas chromatograph oven, a gas detector, a sample gas moving device, and a flow detector. An example of a method for detecting gas includes flowing a sample gas from the oven, determining whether the flow rate equals or is less than a minimum, and determining whether the concentration of a first gas of the sample gas, such as a combustible gas, equals or exceeds a maximum. If either the flow rate or the concentration indicates an error condition or is out of bounds, an alarm response is initiated. The alarm response may include shutting off the flow of the first gas to the oven, and flowing a second gas, such as a safe gas, to the oven.
摘要:
A flow through isolation valve having a stationary member; a movable member, with a surface of the stationary member interfacing with a surface of the movable member; and at least one pin isolation valve. The pin isolation valve has a flow through internal conduit and is movable so that the internal conduit can fluidically communicate with at least one blank opening in the movable member and with a flow through internal conduit in the movable member. Movement is by rotation, linear or curvilinear translation. At least one pin isolation valve is fluidically coupled typically to a sample loop of a face seal valve, or to a pump supplying high pressure liquid to or to a column discharging liquid from a face seal valve of a high pressure liquid chromatography (HPLC) system or directly to the face seal valve.
摘要:
To avoid deposits on the restrictor that channels extractant into a collector, a heated capillary tube pressure release restrictor, has a thermally insulated outlet end in a collecting trap substantially colder than the capillary tube. The restrictor is heated between the insulation and the capillary tube by Joulean heating. The solvent in the trap is at a pressure of 5 to 200 psi above atmospheric pressure. The thermal resistance of the insulation is selected to reduce the heat added to the extractant to a minimum and yet cause the temperature of the extractant to be in a range within which it is sufficiently hot so it does not freeze when added to the collection solvent but not so hot as to reduce partitioning of the extract and extractant before the extractant leaves the collection solvent. It has a thermal conductivity no greater than 60 BTU's per hour, per square foot, per inch for a one degree Fahrenheit difference.
摘要:
A chromatograph includes an inlet for receiving a sample and a pressurized hydrogen gas flow and in response providing a sample/fluid mixture; a separation column located in a temperature-controlled zone for receiving the sample/fluid mixture and for providing a column effluent stream; a detector for receiving the effluent stream and for providing a detector output stream; and a gas storage system for receiving the detector output stream (and optionally a split flow and a septum purge flow in the instance of a split/splitless inlet) and for storing the received gas stream for subsequent reuse. In the preferred embodiments of the gas storage system, a plurality of metal hydride storage (MHS) systems are used.
摘要:
The relationship of variations in the retention time of a specific component of a measurement blood sample with respect to changes in change-over time of the eluting solution is determined. The retention time of the specific component of the measurement blood sample is measured under a particular analyzing condition. In case of a departure of the retention time from a predetermined reference range, a change-over time of eluting solution is obtained in accordance with the relationship, so that the retention time of the specific component can fall within the reference range. The change-ever time of eluting solution is updated as an analyzing condition for the subsequent analysis by using the obtained values.
摘要:
A method and device are disclosed for performing supercritical fluid chromatography in packed columns of at least about 0.5 mm inside diameter. The column provides at least 50,000, preferably at least 100,000, theoretical plates with pressure drop across the column of at least 25 bar. The outlet pressure is controlled by the back pressure regulator. The column may comprise a plurality of individual columns in series. Separation is performed at a rate of at least 25 plates/min, preferably at least 100 plates/min.
摘要:
To supply supercritical fluid to an automatic supercritical fluid extractor and collect extract from the extractor, sample holding cartridges are lifted one by one in series by an elevator plug into a pressure chamber. An inlet at the top of the cartridge engages a pressure vessel inlet for the extractant so that extractant flows into the cartridge and into the space between the cartridge and inner walls of the pressure chamber. The outlets from the cartridge and pressure vessel communicate with the collector and exhaust through passageways in the plug. The plug has cleaning ports for cleaning seals and the outlet from the cartridge flows past the seals. The collector lifts vials into place and can precool the collection solvent, and later as part of the collection procedure, heat and pressurize the collector.
摘要:
An apparatus for supercritical fluid extraction incorporates a removable extraction cartridge which in operation has insignificant pressure difference between its inside and outside walls. In one embodiment, the extractor includes a fraction collector for extractants, an automatic sample changer and an automatic cartridge transfer mechanism which provide completely automated extractions. To automatically perform extraction, valves for the fluids are automatically opened and closed in synchronism with the insertion and removal of the cartridges. These valves force a hard valve element into a softer valve seat with a valve stem that does not rotate significantly under the control of a rotary motor.