I noticed recently that the ECD back signal on Agilent GC 7890 (using it for trace gas analysis) is oddly spiking (while the FID is a straight, consistent line). It never used to do this. I just recently changed the inlet septum, could this be as a result of incorrect installation of the new septum? I've attached a screenshot of what it looks like. Am I still ok to run my samples, or is this a serious issue?