Peak fronting and distortion in UPLC systems - WKB12219

SYMPTOMS

• Peak fronting and peak distortion (see figures below)
  

ENVIRONMENT

• ACQUITY UPLC SM
• ACQUITY UPLC I-Class
• ACQUITY UPLC H-Class
• ACQUITY UPLC

CAUSE

• The sample diluent is too strong (stronger than gradient beginning) and Full Loop injection mode is applied.
• The weak wash solvent is too strong.

Weak wash issues are seen in Partial Loop (Pressure Assist) mode.

FIX or WORKAROUND

1. Reduce the percentage of organic solvent in the sample diluent (sample diluent should be weaker or equal to gradient beginning).
2. Reduce injection volume (dilute sample with weak wash solvent during injection).
3. Change Injection mode to PLUNO (Partial Loop with Needle Overfill).

ADDITIONAL INFORMATION