GC-FPD - peak in blank

[stanniie]

Hi,

I am running samples on GC-FPD.

My calibration and sample peaks were all tailing so I was suggested to cut the end of the column from the detector and increase the carrier flow rate.

As I was cutting the column I noticed the detector inlet was not in the correct amount so I adjusted for that as well.

After cutting I ran my blank and did a bakeout. I have a total of 3 chromatographs (after column cut) and they all have an unidentified peak that was not present before.

Any suggestions on what I should do next?

[James_Ball]

I would think it is more on the inlet side of the column. Usually such problems come from high boiling point organics or inorganic materials accumulating in the inlet and the front end of the column, not so much the detector end.

Have you changed injection port liner or remove a few centimeters from the inlet end of the column?

[AICMM]

Three questions. 1) Sulfur or phosphorous mode? 2) Peak with no injection, just an oven run? 3) Sharp peak, ugly broad peak, what kind of peak?

Best regards,

AICMM