Oil response decreasing

[Morphy]

My oil response has been decreasing. I change the liner and recal but this has not helped that much. Any suggestions or clues as to what the problem is?

Thanks

[Consumer Products Guy]

More information is needed. And by oil, do you mean petroleum or liquid fatty acid triglyceride?

[Morphy]

[quote="Consumer Products Guy"]More information is needed. And by oil, do you mean petroleum or liquid fatty acid triglyceride?[/quote]

Petroleum Oil. My GC is a FID btw

Nice to meet you.

[skunked_once]

Murphy,

We still need more information in order to help you.

My oil response has been decreasing.

Do you mean that the results from the analysis are less than before or that your peaks are getting smaller or something else? Please explain in more detail. A complete list of your analysis conditions would help as well as information of whether this happened gradually or all at once.

[skunked_once]

Murphy,

Oops, I mean Morphy Must be thinking of Murphy's Law which applies to most of the posts on this forum

[Morphy]

[quote="skunked_once"]Murphy,

Oops, I mean Morphy Must be thinking of Murphy's Law which applies to most of the posts on this forum [/quote]

The area under the peak is getting less gradually. I seem to have to recal every two weeks.

It has been getting worse for about two months now. My analysis time is 40 minutes. I am wondering if it is the jet?

Thx for your interest.

[skunked_once]

Morphy (and others with questions),

When you call the repair shop to tell them that your car is broken and won't run the first thing the mechanic will ask is what kind of car is it, which engine, etc. He (or she) needs to know as much as possible about the vehicle in order to diagnose the problem.

So: Tell us all about your analysis conditions including brand of GC, carrier gas and detector gases with all flow rates, type of injection (split or splitless), column type and dimensions, temperature program, inlet and detector temperatures. Tell us more about your samples, sample prep, etc. Finally, what maintenance do you regularly perform and what have you tried since the problem began. Posting chromatograms of good runs and poor runs also helps. Have peak shapes or retention times changed? Has anything else changed in the lab? We look forward to your replies.