Gas chromatographic system with controlled sample transfer
AssigneeThe Perkin-Elmer Corporation
InventorJohn V. Hinshaw
Life of this patent
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Abstract
In a gas chromatographic system that includes a column and an injector with a chamber, a carrier gas normally flows into the chamber at a constant rate, and a constant primary pressure is maintained at the column inlet. A sampling receptacle selectively communicates a sample vessel with a source of transfer gas or the chamber. The vessel is pressurized with the transfer gas to a starting pressure greater than the primary pressure. Analyte sample in transfer gas is then tranferred from the vessel to the chamber by the vessel pressure while the vessel pressure remains greater than the primary pressure. Carrier gas flow is discontinued during transfer, so that analyte sample transfers through the chamber into the column by the primary pressure linearly with time. Standby and venting states are provided.
Claims16
A method for transferring analyte sample in a gas chromatographic system that includes a gas chromatographic column with a column inlet, injector means with a chamber selectively receptive of a carrier gas flow and an analyte sample in a transfer gas with the chamber communicating with the column inlet for injecting carrier gas and sample into the column, flow means for effecting a carrier gas flow into the chamber at a constant flow rate, primary pressure means for maintaining a constant primary pressure at the column inlet, a transfer pressure source of a transfer gas, and transfer means for selectively communicating a sample vessel with the transfer pressure source or the chamber, the sample vessel containing an analyte sample, wherein the method comprises steps of initially pressurizing the sample vessel with the transfer gas from the transfer pressure source so as to effect a vessel pressure at a starting pressure greater than the primary pressure, and communicating the sample vessel with the chamber so as to transfer analyte sample in the transfer gas from the sample vessel to the chamber by the vessel pressure while declining from the starting pressure during a transfer period, the transfer period being such that the vessel pressure while declining from the starting pressure remains greater than the primary pressure, with the pressurizing and the carrier gas flow discontinued, whereby analyte sample is transferred through the chamber into the column by the primary pressure linearly with time during the transfer period.
A gas chromatographic system comprising:
- a gas chromatographic column with a column inlet;
- injector means with a chamber selectively receptive of a carrier gas flow and an analyte sample in a transfer gas, the chamber communicating with the column inlet for injecting gas and sample into the column;
- flow means for effecting the carrier gas flow into the chamber at a constant flow rate, including means for discontinuing the carrier gas flow during a transfer period;
- primary pressure means for maintaining a constant primary pressure at the column inlet;
- pressurizing means for pressurizing a sample vessel containing an analyte sample, the pressurizing being effected with the transfer gas to effect a vessel pressure at a starting pressure greater than the primary pressure;
- and
- transfer means for communicating the sample vessel with the chamber so as to transfer analyte sample in the transfer gas from the sample vessel to the chamber by the vessel pressure during the transfer period, the transfer period being such that the vessel pressure while declining from the starting pressure remains greater than the primary pressure, with the pressurizing and the carrier gas flow discontinued, whereby analyte sample is transferred through the chamber into the column by the primary pressure linearly with time during the transfer period.
A gas chromatographic system comprising:
- a gas chromatographic column with a column inlet;
- injector means with a chamber selectively receptive of a carrier gas flow and an analyte sample in a transfer gas, the chamber communicating with the column inlet for injecting gas and sample into the column;
- flow means for effecting the carrier gas flow into the chamber at a constant flow rate, including means for discontinuing the carrier gas flow during a transfer period;
- primary pressure means for maintaining a constant primary pressure at the column inlet;
- a transfer pressure source of a transfer gas;
- transfer means for selectively communicating a sample vessel with the transfer pressure source or the chamber, the sample vessel containing an analyte sample;
- and
- control means operatively connected with the transfer means for operating the chromatographic system through a set of operational states comprising, in sequence:
- a pressurizing state for pressurizing the sample vessel with the transfer gas, with the sample vessel being in communication with the transfer pressure source so as to effect a vessel pressure at a starting pressure greater than the primary pressure;
- and
- a sample transfer state for transferring analyte sample in the transfer gas from the sample vessel to the chamber by the vessel pressure during a transfer period, the transfer period being such that the vessel pressure while declining from the starting pressure remains greater than the primary pressure, with the pressurizing and the carrier gas flow discontinued, whereby analyte sample is transferred through the chamber into the column by the primary pressure linearly with time during the transfer period.
Dependencies are inferred from the claim text.