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- Posts: 6
- Joined: Mon Jan 22, 2018 5:48 am
I am attempting an analysis of Lactulose (a dissaccharide) using with the following setup:
- Waters System 600-717 Plus-2414 (RID)
- 150 mm x 4.6 mm, 3 micron NH2 Column
- Column and Detector temp: 38C
- Sensitivity: 128
- Mobile Phase: ACN:Buffer(Sodium dihydrogen phosphate) = 80:20
- Flow rate: 1.0 ml/min
- Injection vol: 20 microlitre
However I observed a retention time that is drifting in the forward direction (becoming earlier) between injections (19 mins, 18 mins, 17 mins...) of same sample.
Have anyone of you come across such cases? Is there a particular reason for the forward drift of the injections?
Your advice is much appreciated!