Retention time shift and poor chromatographic resolution of peaks after the first injections - WKB12700

SYMPTOMS

• First injections, peaks elute at correct retention times
• Second injection, peaks elute at much earlier time and nearly co-elute
• Third injection, peaks co-elute at very early retention time
• Found: eluant is more than 30 days old

ENVIRONMENT

• ACQUITY UPLC H-Class
• HILIC Column
• Reverse-Reverse Phase chromatography
• Eluant: Acetonitrile (no additives), Water (0.05 mMol Ammonium Acetate)

CAUSE

Acqueous solvent degraded

FIX or WORKAROUND

Prepare new solvent

ADDITIONAL INFORMATION