Chromatography Forum

We have an HP5890 Series II GC interfaced to a HP5972 MSD and Tekmar 3100 P&T. We have recently been splitting the sample with a jet separator but are now in the process of removing it and splitting the sample through the injection port. Our column that''s being used is an Agilent 25m DB624 (model number 128-1324). Basically, after changing over, our problem is that we are not getting the EPC to work at all. There is also no flow coming out of the split vent, but there is flow going into the injection port and flow through the column (although not as much as I think there should be). The EPC reading is 0.6, and no matter what value you use to program it (say 10.0, for example), the reading does not change from 0.6. I've replumbed the injection port to make it active by taking the split vent line "S" attached from injection port and attached the other end to the bottom of split vent solenoid. I cut the carrier line "C" approx. 2" from the main body of the injection port, and connected the short end to the transfer line of our Purge and Trap unit and the longer end was then connected to the "Carrier In" fitting on P&T. I adjusted the DIP switches on EPC board and changed them to reflect using EPC. I zero calibrated the EPC . I installed a new gold seal and put in a new liner-4mm gooseneck. Any help and correspondence on this problem would be greatly appreciated.

Acrolein,

Sounds to me like one of three things. One, you have a leak that does not supply enough total flow to the injection port for the EPC to maintain back pressure. Possibly a missing o-ring on the gas fittings at the split valve? Two, you have not given the injection port enough total flow (via the total flow controller) for the EPC to meet its needs. Three, you have plumbed the splitter valve incorrectly. Go look at one of your split splitless injectors on your SVOA and make sure the tubes go to the correct locations.

Best regards.

AICMM,

Thanks so much for your input and suggestions. Turned out it was a bad o-ring as you suggested on the purge line. I replaced it, as well as a couple others on the gas line path and I'm now getting pressure and good flow. Thanks for your help again!