PDA baseline noise (Guided Troubleshooting) - WKB97186

SYMPTOMS

• Baseline noise in PDA chromatogram.
• SQT test failing for noise specification.
• Customer having issues with quantification at lower levels.

ENVIRONMENT

• ACQUITY UPLC PDA Detector
• ACQUITY UPLC PDA eλ Detector
• 2998 Photodiode Array Detector
• ACQUITY Arc PDA 2998

STRATEGY

1. For ACQUITY PDA, inspect 250 psi back pressure regulator - WKB10081
2. On ACQUITY PDA, m​​​​inimize refractive index effects. If running at low UV wavelengths (less than 205 nm):
   1. Sonicate mobile phases - WKB1529
   2. For QSM, place all lines in a single mobile phase bottle - WKB95837
   3. If using a 30 cm column heater, insulate column outlet lines - WKB1035
   4. If possible, turn on Median Baseline Filter (MBF) - WKB95839
3. Inspect flow cell
   1. Clean flow cell - WKB9482
   2. For 2998, rebuild flow cell - WKB13746
   3. If necessary, replace flow cell - WKB23351
4. Replace lamp - WKB20304
5. Inspect solvent manager for pressure fluctuations
   1. If necessary, replace check valve - WKB73348
   2. If necessary, rebuild pump  WKB74137

ADDITIONAL INFORMATION