How do I overcome low sensitivity during start-up?

Running a 7800 ICP-MS and during the past two weeks have been experiencing difficulties. The doubly charge percentage has continually risen with each day of testing. I have removed and cleaned the cones and lens stack and conditioned before use. I checked the nebulizer and spray chamber for blockages and build up and didn't find anything. I have removed and cleaned the torch/bonnet in a 5% HNO3 solution overnight then dried and replaced the components. 

After all these steps I started up went through the warm-up process and then received the following error during plasma correction.

HW Settings: Plasma Correction 

Hot plasma correction failed because sensitivity is too low(140 u below 3000 CPS). Ensure the tune solution is being introduced into the instrument. Check the sample introduction system (Nebulizer, Spray chamber) and carry out maintenance if needed. 

I spoke with Agilent and overrode the plasma correction error, but then the machine errored again during Auto tune as the auto tune failed due to low sensitivity as well. 

Any suggestions on what to do next is there something obvious that I am missing? 

Anything helps thank you! 

Parents Reply Children
  • Hello! I know you dealt with this issue last year, but we are experiencing the same problem, but on a 7900 ICP-MS. However, we are seeing no counts of mass 140. Could you point us to the direction of the bracket plate sensor that you are referencing? I did a search on agilent's store and could not find it anywhere. 


    I also saw your previous posts regarding your oxide/doubly charged ratios. I'm not sure what your application is, but on our system, we have been successful in keeping ours under 1.5%. I know you posted it a while ago (so I'm assuming you figured it out already), but if not, I have some solutions that you can run through your system that might drop it lower. 



  • The bracket is located underneath the torch box, it is part of the gold color contact piece that the platinum shield grounds too. This piece was sent directly from our field service technician and she walked me through the replacement. 

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