No peaks and poor chromatography on an H-Class system - WKB24767

SYMPTOMS

• No peak for caffeine sample
• No peaks running the gradient test
• Pressure trace does not change with gradient changes for AB and CD
• Pump and system leak tests fail
• Peaks returned with GPV replacement show tailing and lower sensitivity
• Peaks missing again after I2V check valve replacement and primary head rebuild
• Peaks return with removal of sample loop
• Wash of system with phosphoric acid shifts retention times

ENVIRONMENT

• ACQUITY UPLC H-Class

CAUSE

Injection valve leaks to waste during injections.

FIX or WORKAROUND

Replace the injection valve cartridge (700005236).

• See section 3.12 in ACQUITY UPLC SM-FTN Overview and Maintenance Information (715005051)

ADDITIONAL INFORMATION