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- Posts: 3
- Joined: Fri Oct 27, 2017 1:37 am
Over the last week one of our 1100's has had this problem:
https://ibb.co/cszKVm
With this pressure curve indicating a problem, the expected peaks are just all over the place. Often not even showing up until the next run.
Instrument:
Agilent 1100 Quaternary pump
The run conditions during this run are:
Mobile Phase A - 0.1% H3PO4
Mobile Phase D - Acetonitrile
Flow Rate: 0.4 mL/min
Column: C18 150x4.6mm 2.6um
Things tried so far:
-Complete flush with ACCN/MeOH/Iso/H2O on all four channels at high flow rate.
-Pump seals and check valves replaced.
-Pressure/leak test performed (pressure tightness confirmed; everything passed)
-Gradient test, gradient proportioning valve tests (using H2O on A/B and 0.5% Acetone on C/D) all passed
My gut is telling me that the valve is unable to proportion acetonitrile and that the low pressure mixing isn't happening. Has anybody dealt with a pressure curve looking like this?
Any help would be greatly appreciated. Thank you.