When I start our Agilent 7700x quadrupole ICP-MS, the plasma comes on, moves towards the cone and then shuts down producing the following error message:

1230, Error: Plasma was shutoff when opening gate valve

and occasionally:

1135, Error: Malfunction on gate valve open. Valve closed again.

Things I tried to fix the problem:

1. Switch from laser ablation to solution mode. This initially produced two new error messages:

1233, Error: RF generator has switched 48V power supply off
1218, Error: Plasma was shutoff (Plasma RF Monitor)

2. Cut back the fibre-optic cable in the source. This removed errors 1233 and 1218 but brought back errors 1230 and 1135.

I don't know if this is relevant, but the MassHunter software briefly reports an Analyzer Pressure of 8E+6 Pa immediately after the error. Then it changes back to the usual 9E-6 Pa. I don't know if this has anything to do with the problem. A megapascal of pressure seems rather impossible.

Pieter Vermeesch
London Geochronology Centre
University College London