Chromatography Forum

Hi All,

I had this happen to me twice lately. I would appreciate if you guys/gals help me pinpoint where the issue exactly is. I am somewhat comfortable performing my own fix, but do not want to dissassemble everything without knowing what might be wrong with the system.

https://imgur.com/a/5O5W3Cp

Above image shows a sudden loss in pressure and subsequent stuttering.

I am suspecting a primary pump check valve failure.

I am positive that there are:
1) No leaks from pump heads
2) No air trapped in the system
3) Nothing wrong with the column

Thanks in advance!

Check valves. Time for new ones.

Appears to be no signal due to complete loss of prime. Basic troubleshooting must start to solve. Make sure the pump has been fully inspected and serviced (PM service). Next, prime ALL of the channels of the QSM, one-at-a-time with IPA. Check the outlet check valves to insure each one is primed (easy to do by cracking open the top fitting while pumping to confirm liquid wants to come out and it is not just pulsing back-and-forth). Verify the liquids being introduced to the pump are degasser (For a Waters Acquity QSM system, the degasser will last a maximum of five years before requiring replacement or professional service). It will be broken after this time period (normal lifetime). The degasser "error" warning only appear long after the degasser is broken (sometime years after it is broken!) so do not rely on them.

Here is an authoritative article on diagnosing these types of pressure issues:

• "Diagnosing & Troubleshooting HPLC Pressure Fluctuation Problems (Unstable Baseline) "

; https://hplctips.blogspot.com/2014/01/d ... -hplc.html