Importance

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Abstract

A precolumn separator provides a method of separating a solvent from a sample for use in a gas chromatograph. The precolumn has an independent carrier gas control mechanism which allows the carrier gas to be passed through the preseparation column at a rate favorable for stripping the solvent from the sample. The solvent-laden carrier gas is then purged through a purge vent which is separate from the gas chromatograph. After a period of time which effectively permits the carrier gas to be significantly removed from the sample, the flow rate of the carrier gas is reduced to the normal operating gas flow rate and the purge vent is closed. The sample is then passed through the column to the gas chromatographic column. A second purge vent can then be directed to the purge vent inlet in the gas chromatograph. Preferably, the preseparation column is a packed column which includes a separate heating element. The heating element, in turn, can be surrounded by an air cooled jacket. The air cooled jacket has an inlet at the bottom of the preseparation column and a spiral flow path around the heater. This will cause the bottom of the preseparation column to be cooler than the upper portion which, in turn, will cause a compression of the sample near the outlet. This permits stripping of a significant amount of solvent from the sample while, at the same time, eliminating the need to match the sample injection rate to the solvent evaporation rate.

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First Claim