What could be the problem,
If you see no peaks at all, possible causes include:
- injector malfunction (nothing was injected)
- pump malfunction (no flow of mobile phase)
- detector malfunction (no signal)
- data system malfunction (signal not detected or recorded).
If you see *some* peaks and t0 is correct, but your creatinine peak is missing, possible causes include:
- it was never there in the first place. Check that your standard was correctly made up, and then re-run the standard.
- it was there, but now has gone. Make up a fresh standard and re-run.
- it is there, but you can't see it. Check the detector wavelength setting and sensitivity.
- it has moved. Check to see if any "new" peaks have appeared; if none are found, check to see if any of the other peaks have increased in area. If so, the problem is due to a change in the selectivity of your system. In this case, you should consider the following steps:
-- Check that the column temperature is correct (if the column compartment temperature setting is correct, use a thermometer to confirm the actual temperature).
-- Check to confirm that the mobile phase was correctly prepared (especially if the problem coincided with a new batch of mobile phase!).
-- Check to make sure that the correct type of column is being used (I'm not being sarcastic here; I've done it!
-- If the column is nearing the end of its useful lifetime, replace the column.
