By Anonymous on Monday, August 4, 2003 - 07:12 pm:
Everybody,
GC with FID.
Everytime a very large peak is here in chrom after the instrument start work.( not caused by ignition)
Does it mean FID or Column was contaminated?
By Jason Ellis on Tuesday, August 5, 2003 - 08:56 am:
Do you mean that you see a large peak elute from the column on the first run (temperature program) after the GC has been sitting for a while? Is the peak always at the same retention time? If it is always at the same RT and only elutes on the first run after the GC has been idle for a while, then it is a strong indication that the contamination is coming from upstream of the column. This could be a contaminated inlet, poor carrier gas quality (bad gas supply/purity or saturated gas purifier) or septum bleed. Try cleaning the inlet and see if that helps.