Signal is fading with time in both polarities (TOF MS instruments) - WKB11902
Article number: 11902
SYMPTOMS
- Signal from direct infusion is decreasing with time
- Polarity switch temporarily resolves the issue
- Signal decrease is independent of polarity
ENVIRONMENT
- Xevo G2-S Qtof / TOF
- SYNAPT G2-Si
CAUSE
- Charging of ion block
- Clogged ESI probe capillary
- Clogged LockSpray capillary
FIX or WORKAROUND
- Verify that the probe capillary is not clogged and that the spray itself is stable. If not, rebuild the probe following the procedure from the user guide (pages 147-154 for ESI probe, pages 162-165 for LockSpray probe).
- Clean the ion block using the cleaning procedure from the user guide (pages 111-124). If the ion block is damaged, replace it with a clean spare (part number 700009088).
- Pump the instrument down, and verify that signal stability is restored.