trouble with FPD chromatogram....pesticides

[christine_mci]

I am running OP Pesticides on a GC-FPD (dual... S and P). I was able to run standards as low as 15ppb for a few months, but now I am getting terrible results. The peaks (well the ones that will show up) are broad and distorted.

I have not made any changes to the method program. I have changed out the liner, septum and trimmed the column on both ends.

Any more suggestions??

Thanks.

[tolo]

1. did you replace the gold plate in the inlet
2. did you check for leak in the system
3. did you check for height of ferrule to the front end of column in the inlet (4-6mm for the agilent inlet
4. did you check for height of ferrule to the rear end of column in the detector side (153mm for old agilent FPD, 145mm for enhanced agilent FPD)