Discussion Category:  HPLC Pumps

Agilent 1100 Retention times shifting

I am running a reverse phase system on an Agilent 1100 with a quantenary pump.  My retention tiimes are shifting and the pressure is higher while running. 


Also when the purge valve is open the pressure is higher than it used to be.


I think I need to do the PM on it but wanted to see if there was anything else I should look at.

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DKH@Pace_ISGReply by

Higher pressure with the purge valve open almost always means the in-line PTFE frit in the purge valve is plugged. Replace that, and then check the pump's flow rate volumetrically using your method and column (e.g., ensure it takes 10 minutes for 10 mL to come out the waste line when running at 1 mL/min). A low measured flow rate is likely due to a leak somewhere. If the pressure is also fluctuating, it'sprobably a bad active inlet valve or cartridge. If the flow rate is okay and you're running a gradient, it's probably your gradient valve or your column.

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