Dropout at apex of chromatographic peak on Xevo G2-XS QTof - WKB11798

SYMPTOMS

• 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

ENVIRONMENT

• Xevo G2-XS QTof 
• MassLynx 4.1

CAUSE

The detector has hit the point of saturation at the most intense (apex) part of the chromatographic peak. 

FIX or WORKAROUND

1. Increase the scan time or decrease the concentration of the injected sample.

ADDITIONAL INFORMATION

Saturation occurs at about . . .

• 1e7 for a 1-second scan time
• 1e6 for a 0.1-second scan time
• 3e5 for a 0.03-second scan time