When peak elutes, 2475 FLR or ACQUITY FLR detector records a negative response - WKB91369

SYMPTOMS

• When peak elutes, detector records a negative response, sometimes dropping sharply to -10,000 EU and producing a flat bottom peak

ENVIRONMENT

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

CAUSE

The PMT (Photomultiplier Tube) is oversaturated and responds by exhibiting negative response

FIX or WORKAROUND

1. Dilute the sample
2. Lower the PMT gain setting

ADDITIONAL INFORMATION

This picture shows the 2475 baseline drop