QDa fails positive mass accuracy test; mass accuracy is more than 200 mDa - WKB97401

SYMPTOMS

• Mass accuracy test over five compounds (acetaminophen, caffeine, sulfadimethoxine, reserpine, terfenadine) always fails
• Some or all measured masses > 200 mDa compared with theoretical

ENVIRONMENT

• ACQUITY QDa Mass Detector
• Empower 3
• Qualification tests 
• Startup tests

CAUSE

Sampling rate in the instrument method is higher than 5 points/sec.

Example: At 10 points/sec, mass accuracy test fails and most of the measured masses are over 200 mDa specification.

FIX or WORKAROUND

Set 5 points/sec in the sampling rate feature to be accurate against the specifications and to pass the test.

ADDITIONAL INFORMATION