I have an odd problem tracking down an air leak in my 5890/5972. During a run, about every 15 minutes I get a brief spike that looks like an air leak. I've tried isolating the MS first by capping the transfer line. No more spikes. After reconnecting with a new ferrule, I checked for leaks with dust-off by scanning ion 51, and everything inside the oven seemed fine, so I did another run, and still had peaks. So, I disassembled the inlet completely and replaced everything from septum, liner, seal & etc. On my next run, the peaks are back.
I did notice something strange. This problem started when I switched to a new SGE column, and looking at it carefully, I see that the polyimide coating on the outside of the column seems to be in poor shave with pitting. Could a column flaw cause this problem?