-
- Posts: 38
- Joined: Tue Sep 13, 2022 1:09 pm
- Location: USA
We are having trouble with an unresolved, fairly large leading interference peak on the M+ 58 (confirmation ion) SIM that tails over the top of the smaller confirmatory ion peak at the LOQ. I am fairly sure it is a hydrocarbon of some sort. The solvents are clean, but the signal is still there for every injection. (Note that this is a peak and not a continuous background interference). I believe it is hydrocarbon-based because it also has the co-eluting M+ 43 signal.
We have tried new He cylinder, a new "large" He hydrocarbon/O2 scrubber. cleaning the injector, a new inlet liner, new septum, new column (all have been conditioned) and a new injector syringe. Also baked out the MSD and source.
Has anyone encountered this with EPA 522 or similar method? Anyone have suggestions?