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- Posts: 3
- Joined: Fri Oct 19, 2018 2:59 pm
Column 10x250mm Atlantis T3 (C18)
Mobile phase A=water, B=Acetonitrile, C=2% Formic acid in water
Flow rate 4.6 mls/min
Initial 45%A, 50%B, 5%C
30mins 55%A, 60%B, 5%C
31mins 0%A, 95%B, 5%C
32mins 0%A, 95%B, 5%C
33mins 45%A, 50%B, 5%C
cycle time 45 mins.
Injection volume 4 mls
My peaks of interest elute at 31 and 32 minutes as a partially resolved pair. For the first 15 or so injections these retention times were fairly constant, then there was a period where the retention decreased by 0.5 to 1 minute per run, then it would stabilise again, then drift again, etc, etc. By the end of 54 injections the retention times were approx 14 minutes and the separation very poor.
Does anyone have any ideas on whats causing this and/or what we can do to try and get the retention back?
Many thanks
Chris