Retention times shift, peaks co-elution (M-Class) - WKB7504

SYMPTOMS

• Peaks that are usually resolved are co-elution
• Typical retention times for peaks are shifted

ENVIRONMENT

• UPLC M-Class
• nanoACQUITY UPLC

CAUSE

Flow transducers need to be re-zeroed, usually due to the changes in lab environment

FIX or WORKAROUND

1. Check firmware version, and ensure that instrument has the latest version (currently for M-Class only firmware needs to be upgraded to version 1.56).
2. Perform Autozero Flow Transducers procedure for both pumps. Verify that results are "Pass".
3. Perform a test with a known sample to ensure that the issue is resolved. Occasionally, it may take up to 10 injections to get the new flow rates settled.

ADDITIONAL INFORMATION

New firmware (1.56) for the M-class uBSM improves the ruggedness of the auto-zero calibration and fixes the uBSM actuator cycle prior to the gradient. It is recommended to upgrade existing 1.53 or 1.55 firmware to this version as soon as possible.

Link to download new firmware and supporting documentation: http://www.waters.com/waters/support...enttype%7CDWNL