Why did we get so high darbly charged ratio (305.13% and 68.337%) for ICP-MS 7800?

Hi Team, 

1. We run the performance check before I set my tune mode, everything including the doubly charged  70/140 ratio (1.269%)  is fine 1.269%.. 

2. however, my tune report showed me a 305.13% of doubly charged ratio in no He mode, and 68.337% in He mode. (see below the pictures) 

previously we ran the same method and did not find anything wrong. 

3. we are testing Li, Al, V, Co, Ni, Cu, As,  cd, Sb, Hg and Pb. 

4. Could anybody please tell me what happened?  

Thank you

best regards, 

Di Xu

Was this helpful?