- A rectangular slice is missing at the apex of the chromatographic peak
- Mass spectral ions at the apex of the peak are marked with "?" peak flags
- Upside-down "?" peak flags
- Detector saturation
- Xevo G2-XS QTof
- MassLynx 4.1
The detector has hit the point of saturation at the most intense (apex) part of the chromatographic peak.
FIX or WORKAROUND
- Increase the scan time or decrease the concentration of the injected sample.
Saturation occurs at about . . .
- 1e8 for a 1-second scan time
- 1e7 for a 0.1-second scan time
- 3e7 for a 0.03-second scan time