Those spikes look like electronic signals caused by the a gap between the column and FID detector. Check to make sure the column is cut the correct length. Make sure it’s not trimmed at a weird angle or cracked. You could also clean/replace the FID Jet. Hold the Jet up to the light and look to see if anything is plugging the hole. To prove it’s the detector, plug the detector inlet and turn the FID on, essentially isolating the detector from the inlet and column. If you still see sharp spikes, then the problem is isolated to the detector. I suppose low purity gases can cause reactions at high temps leading to some signal spikes. I have also seen this spiking occur after changing gas cylinders. You definitely need to purge your FID with any newly replaced gas cylinders to get out any impurities caused by the changeover.
I trimmed it back, reset to 65mm on the tool, tightened it up and put it back into the detector. Baseline is currently stabilizing, we’ll see the results shortly. I think I’ll do a bake out at 350c for an hour or so, see how it looks before running the sequence.
For a bake out run, I like to cut head off column, reverse column (head is now at detector), and hold at the max column temp quoted by vendor minus 2C for 3hrs at normal gas flow. Detector at max temp also. Re-reverse column afterwards.
Would be good to change inlet hardware (gold seal, septum) before bake out. Also flush carrier gas through column at room temp (~10min) before raising temp due to O2 in atmosphere reacting with stationary phase at elevated temp.
