Chromatography Forum

Hi I would like to connect an old 6890 to a 6 port gas sampling valve but the only carrier control is a split split less EPC . What is the best way to connect this to the Gas sampling valve without going through the injector ? Can it be cut off and connected directly and tricked into a readback to the EPC ?

Hi I would like to connect an old 6890 to a 6 port gas sampling valve but the only carrier control is a split split less EPC . What is the best way to connect this to the Gas sampling valve without going through the injector ? Can it be cut off and connected directly and tricked into a readback to the EPC ?

The pressure reading comes from the split vent line so it will have to go through the inlet, but you can cut the line that supplies gas coming into the inlet top, run it to the gas sampling loop then out of the valve and back to where you cut the line going into the inlet. This is how most people plumb in purge and traps or headspace samplers. You can then do either a split or splitless injection from the gas sampling valve and loop and have the EPC control the pressure and flow.

I concur with James. This is how most of my customers tie a valve into an inlet. However, they usually do it because they want to split the incoming sample. Very important to cut the right line when you do this!

the other option would be to place a transfer line from the inlet to the 6-port valve and then from the valve to the column in the oven.

Keep in mind that in this scenario, you are very limited in the flow dynamic through the valve loop and could cause peak broadening.

Best regards,