We currently deal with the folowing problem:
Our ICP-MS is an Agilent 7500ce and we usually operate it with shield plate. Since severals days, it is not possible to ignite the plasma when the shield plate is mounted. The plasma ignits, immediately fluctates and generates noise synchron to the fluctations. We usually switch off the plasma within 10 seconds manually. Shield plate and torch are completely new, but problem persist. Without shield plate, the plasma is fine.
Thanks a lot