- PDA baseline drifts upward during the organic portion of the gradient
- Lamp was replaced
- Mobile phase was made two months ago
- Solvent A: 99% water/1% ACN/0.1% TFA
- Solvent B: 99% ACN/1% water/0.1% TFA
- ACQUITY UPLC H-Class
- ACQUITY UPLC PDA Detector
Bad mobile phase
FIX or WORKAROUND
- Replace the mobile phase with freshly made solvent.
- Prime the system thoroughly with the new mobile phase.