With ACQUITY UPLC FLR Detector and 2475 Multi-Wavelength Fluorescence Detector, flat baseline observed during sample injections - WKB118075

SYMPTOMS

• Flat, no-noise baseline observed
• Low standards missing; high standards present
• Random baseline spike

ENVIRONMENT

• ACQUITY UPLC FLR Detector
• 2475 Multi-Wavelength Fluorescence Detector

CAUSE

The FLR detector has been powered-on, with the lamp off when not in use, for several weeks, since the last preventive maintenance (PM) or lamp change.  Internal calibration and normalization diagnostics have not been performed since the PM.

FIX or WORKAROUND

1. Remove the LC column and install a union/restrictor.
2. Power cycle the FLR.
3. Flush the flow cell with 100% LC/MS grade (or equivalent) water for 30 minutes at 1.0 mL/min.
4. Perform wavelength calibration.
5. Perform normalization diagnostic.
6. Perform Raman signal-to-noise diagnostic.

ADDITIONAL INFORMATION

See also:

What is "normalized mode" on a 2475 or ACQUITY FLR? - WKB29076

FLR Detector - How often should you normalize? - WKB77456