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Low sensitivity for low masses and high drift ICP-MS 8900

lisbenavides

Hi, we are having low sensitivity for low masses and high drift in our ICP-MS 8900. I've cleaned the lens and spray chamber, the cones and torch are new. I checked the nebulizer for any blockages and replaced the tubing. EM is not reaching near the limit. But the problem still persists. We have received a lot of ¨guides¨ and tests to do from Agilent representatives in Argentina, but no one has worked. We need urgent assistance.

  • 0 in reply to lisbenavides

    It seems like you have a shifted mass scale.

    Are you dealing with user/custom tune, and have selected "override hardware settings" ??

    If so, load a tune with valid settings and override the corrupt values with these ones.

    How did you measure the resistance of the shield?

  • 0 in reply to cschulz

    The above pictures were taken with "override hardware settings" active because Agilent representatives in Argentina asked for: 

    1. Increase 300V approximately pulse and analog voltages until you can do axis optimization with standard startup (do not run the full startup, just axis).

    It wasn't possible to do the axis optimization.

  • 0

    Hi Lisbenavides,  Were you able to resolve the low sensitivity issues?  Our lab is having the same issue after PM.  Any advice will be greatly appreciated.

  • 0 in reply to Metals

    Hi, I'm working in the same lab as Lisbenavides did.

    We do still have the same trouble, specially the sensitivity for low masses. Sometimes the start up throws 300 counts of 7u and sometimes it throws 20000.

    Agilent said us to use a 50 ppm Ca solution in 1% nitric acid for "conditioning the cones", like this article suggests.

    Regards, Lisandro.

  • 0 in reply to lisandrom91

    Hi Lisandro,

     Thank you for reaching out, and it’s good to connect with someone experiencing similar challenges.  It sounds like we’re facing common issue with sensitivity.

    I appreciate the tip about using 50 ppm Ca solution in 1% Nitric acid for conditioning the cones. 

     

    I am glad to report that my low sensitivity issue has been resolved.  An Agilent engineer noticed a smudge of residue on the octupole coming from the gloves in our laboratory. 

    He decided to replace the octupole again using clean, uncontaminated gloves that he brought himself.

    After allowing the instrument to vacuum down overnight, the low mass sensitivity has returned to its normal count and mass 89 and 205 values have doubled compared to their usual levels. 

     

    I hope this information is helpful.  Let me know if you have any questions.

    BTW:  Your email doesn't work

  • 0 in reply to Metals

    Hi Metals.

    I'm glad to see that you could solve the problem! And I'll take special note since our octopole has never been cleaned. We were told by Agilent that cleaning is meant to be done by Agilent's staff only. Thanks.

    Yes, that solution of Ca worked very well for us.

    Sorry, the forum doesn't allow to share email adress. Neverheless, we can keep in touch this way if needed.

    Regards,

    Lisandro.

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