Chromatography Forum

Hi Guys.

i am currently working with three Agilent 6890 GC's and these are sued for FAME analysis.

to produce consistency we determine CF's (correction factors) for each instrument and this usually gives us around 0.1-0.2% difference between the instruments.

Recently, the third instrument has been showing a difference to the other two instruments and is currently 0.7% lower than the other two instruments. the CF's obtained are similar to the other instruments so i must assume that it is injecting the standards properly and the same sample is used on all three instruments but when i inject the same sample on each instrument i get this problem.

Any suggestions to the cause of this/ any remedies?

Cheers

Steve

It's early here and my brain isn't working (not sure when it ever works but that is a different issue) but I am not sure what you mean. By difference between the instruments are you talking about different results, areas, peak times, etc? Are the correction factors for results, areas, etc? A little more information might help.

Need more information, including whether you use a split injection and capillary columns. And next time please make your post title more informative as well.

I'm "guessing" you refer to the relative response factors you get for the various chain lengths????