Retention time shift - WKB21197

SYMPTOMS

• Chromatographic peaks shift in time; problem is seen only on the Xevo TQ MS with the Adlink EP

• On fast scans (e.g., dwell times and ISD of 0.005 s) there may be a problem with the timing of acquired scans

• Retention times of chromatographic peaks may appear to shift by up to -6 seconds for every minute of run time

• More likely with longer run times and later eluting peaks—for example, in an eight-minute run a peak seen at 7.2 minutes (with slow scan speeds)

  may appear to elute at 6.7 minutes

• The total time acquiring the run may also be increased (e.g., an 8-minute run may take nearly 9 minutes to acquire)

• Peaks seen in the ACQUITY Console plots maintain their true retention times

• There may be more scans acquired than the theoretical maximum for an acquisition

ENVIRONMENT

• Xevo TQ MS
• MassLynx

CAUSE

Bug in software: SCN 876, SCN 905, and SCN 950

FIX or WORKAROUND

1. Use a duty cycle (interscan delay + dwell time) of more than 0.100 seconds (100 ms). At this scan speed there is negligible effect on retention times.
2. Install patch SCN 948 (part 667005327), which was released to fix this issue.

ADDITIONAL INFORMATION

See Release Notes