I am using a GC6890N S/N US10124020 Firmware N.06.07 With auto injector and tray: G4513A, SN:CN1540278, FW:A.10.09 and G4514A, CN15450061, A.10.16. We were running on the back detector Splitless, pressure:5.4, Total flow:350.7ml/min, Column Const Pressure, Flow:6.8ml/min DET is FID. Not sure what else would be relevant but I guess on to the QUESTION
On one occurrence the back inlet would not maintain the pressure it always sat 0.1 below the setting. After checking all the normal things, column install, inlet, liner all fittings I moved the column to the front and it ran fine. No other methods run on the back have an issue. Recently another coworker went to run this method on the back again. No pressure issues. After running the method 3 times the system suitability failed area ratio of the peaks all times and areas were sometimes erratic. Making me think it is an injection problem, but as it is a ratio %RSD the ratio of the same vial being injected should not be really effected if the needle has a small air bubble problem effecting the injection volume. The analyst moved to the front inlet same injector, and solution . . . no problems.
The issue method is also the only splitless method we run on the back inlet all other are split and they run fine. Is there something that could get clogged that could affect a splitless method and not a split? Could this be something else.
Any help or suggestion would be greatly appreciated.