Column is not holding pressure for UPLC

nshah4
nshah4
in Software Products
My flow rate is 0.3 ml/min (65% acn) when i bump up the flow rate to 0.3ml/min pressure starts dropping to -10 to 300 to 2000. the usual pressure is around 6000psi. I have perform leak test needle seal test everything looks good and pass. I have purge whole system with Methanol and tried again same things happening. 

Answers

  • shaunwat
    shaunwat
    There must be a leak somewhere. At a flow rate of 0.3mL/min, it may take a while for visual evidence of a leak to buildup. I also caution that most Waters UPLCs are designed to channel leaks into the waste stream without tripping the leak sensors. 
  • nshah4
    nshah4
    so i have performed leak test at high pressure and it passed. I have replaced needle seal and it pass needle seal and characterization test. I have tried all the possible ways to find the solution of this issue.

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