Solvent Vent Mode; Stage 1: Sample And Vent - Agilent Technologies 6890 Series Service Manual

Gas chromatograph

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Programmed Temperature Vaporization Inlet (PTV)

Solvent vent mode

In solvent vent mode, the sample is injected into a cold inlet. During sampling,

and for the duration of the venting, the solenoid valve is open. The solvent

vaporizes and is swept out the vent, while the sample deposits on the liner

walls or packing. If conditions are properly chosen and the sample is suitable,

analytes deposit in the inlet liner while the solvent evaporates and is swept

out. Large or multiple injections can be used to concentrate sample in the

inlet before transferring it to the column for analysis. Figure 240-4 shows the

inlet flow control with the septum head installed.

In the septumless head, the flows are the same as in the septum head except

the septum purge vent is bypassed directly to the carrier flow through the

Agilent 6890 Gas Chromatograph Service Manual

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