High moisture content in GCMS

During tuning my GCMS has high moisture content, but it is free of oxygen and nitrogen. The moisture filter is also ok, I also replaced the helium gas source, but the problem still exists.

Please  suggest me any probable causes?

Regards,

Parents
  • Please turn on the Collision Cell Gases. They must be on during tuning and running the QQQ system. On a 7000x system, the Helium should be 2.25 ml/min and the Nitrogen should be 1.5 ml/min.  It takes fifteen minutes or a bit longer for the Collision Cell temperature to equilibrate after the flows are changed, too, so be a bit patient for best results.

    The air/water test is invalid without them being on and stable.

Reply
  • Please turn on the Collision Cell Gases. They must be on during tuning and running the QQQ system. On a 7000x system, the Helium should be 2.25 ml/min and the Nitrogen should be 1.5 ml/min.  It takes fifteen minutes or a bit longer for the Collision Cell temperature to equilibrate after the flows are changed, too, so be a bit patient for best results.

    The air/water test is invalid without them being on and stable.

Children
  • Hi,

    I turned the collision cell gases on, and waited for long hours even days, but there is no significant difference on the moisture content. I attached the report for your reference. By the way, is it necessarily required to tune with the collision cell gases for scan mode of  analysis.?

  • Hi dag,

    Try varying the column flow to see if the moisture goes up or down with the changes. I have seen where a saturated gas trap will start bleeding moisture into the system. 

    Regards

    James

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