So before you get out your wrenches and screwdrivers, start pushing buttons, turning controls, replace parts or call your boss or the service department, check:
Extract all relevant information from a testchromatogram, check for "ghost"peaks and baseline disturbances. We advise to use a blank or a clean testsample.
Observe the peak shape:
Here are to examples to show how you could approach.
We have two chromatograms. The chromatogram on the left is the expected one. The chromatogram on the right is not what we want.
1. Observe the two chromatograms.
2. Collect your observations.
Here we see:
3. Analyse your observations.
4. Make possible explanations and draw preliminary conclusions
5. Action: Test these conclusions e.g. by changing the relevant parameters
Another example of an unexpected shift in retention times:
What are our observations?
Here we see two chromatograms of a blank temperature run from 0 - 300 0C. The bottom one is the original blank run, the top one after some time of use of the system.
So what could this be?
The quality of the column seems to be no problem since bleeding and noise appear OK.