7800 Low Sensitivity and Low Counts

Hello Everyone,

I have been having gradual issues with my sensitivity and low counts on our 7800 ICP-MS instrument. I have cleaned all of the glassware in a nitric soak, cleaned and inspected cones (which are fairly new), cleaned nebulizer (also very new), replaced all pump tubing, remade new tuning solution, replaced a new graphite gasket, replaced bonnet, etc. After no improvement, I navigated through the Agilent low sensitivity tool and still could not pin point the main issue, I will attach performance report history ( you will see how horrible the counts are), and an example of a recent tune report just in case I am not seeing something I should be. 

Thank you!

  • Hi, I was hoping to actually see the performance report screen with the meters and tune settings to compare. Are you running the full startup each day (torch axis, EM, plasma correction, standard lens tune, res/axis)? Also compare your IF/BK meter and your nebulizer gas BP meter over time. When there is a gradual loss in counts sometimes I can pinpoint it to something slowly drifting up or down like a vacuum pressure or Nebulizer blockage. 

  • Yes! sorry I think I sent the wrong screenshot the second time you asked. I will attach a report from yesterday (October 3rd) which has poor sensitivity, and I will attach a report when my counts were normal (April 26). Also, I do full startups everyday I run with everything you mentioned above.

  • Do you have performance reports you can generate and attach? The EPA tune reports don’t show all the meters :) 

Reply Children
  • I know you serviced the cones already but I would double check the condition of the orifice. Your IFBK is much lower than the previous report where the counts are good suggesting a possible blockage or deformed orifice. 

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