Signal is drifting
The chromatogram baseline is not a straight line. The signal increases or decreases during the time of analysis.
▌ Reason 1: The instability of the analysis conditions.
Check the analysis conditions, the detector settings, the column and solvents for impurities.
▌ Reason 2: Improper connection of the A/D converter (Colibrick, Int9, U-PAD2, ...) .
If you are using the A/D converter, check whether the cable shielding is properly connected. For more information see Fig "Connection of a Clarity station with a chromatograph"