Close the slide valve then check whether the noise is from electronic or plasma 
Regards 


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On Tuesday, June 26, 2018, 9:45 PM, David Jones <[log in to unmask]> wrote:

I have never touched an IcapQ, but that sounds like electronic noise. Some information on the behaviour of the background signals would be needed to confirm this. My guess is either a failing component in the detector side of things or RF shielding, probably around the torch box, not doing its job. If you're lucky it's the shielding and you can quickly find where it has deteriorated or is not fitting correctly. 

David Jones
Chemist, Geochemistry
Brisbane

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-----Original Message-----
From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [mailto:[log in to unmask]] On Behalf Of Prasad Lavisetty
Sent: Wednesday, 27 June 2018 11:10 AM
To: [log in to unmask]
Subject: High Background at 4.5 and 220 mass

Hello,

We have Thermo IcapQ ICPMS, recently we are facing problems with high background at mass 4.5 and 220. The performance at both standard and KED modes are failing in background (both mass 4.5 and 220). I cleaned the cones, nebulizer and spray chamber. I didn't touch the torch and lens. Still the performance is not meeting criteria. Can anybody suggest to solve this problem.

Any suggestions greatly appreciated.

Prasad Lavisetty
Scientist, Teva pharmaceuticals, Inc.
Weston, FL