Turning off the Dynamic Window Extension when using the Scheduled MRM™ algorithm in Analyst® software

For research use only. Not for use in diagnostic procedures.

Answer

Scheduled MRM™ algorithm is a feature in Analyst® software that permits the efficient monitoring of large sets of multiple reaction monitoring (MRM) transitions by slating data acquisition for each analyte in a specific window around an analyte’s retention time.  This feature can be selected in an MRM acquisition method in the Scheduled MRM (sMRM) panel at the top of the acquisition method screen by selecting the Enabled box.

Selecting the Advanced option in the sMRM window reveals the dynamic window extension feature (highlighted below in the pink box), which, when selected, automatically extends the scan window, up to the duration of the scan window. Sometimes, the use of this feature results in lower dwell times for some analytes and inconsistent scan time between analytes, requiring the feature to be deactivated.

In Analyst® software 1.7.x, this can easily be done by unchecking the box for Dynamic Window Extension.

In Analyst® software 1.6.x, the above option is unavailable; however, using a very high value in the threshold column will disable the dynamic window extension feature. The value should be set significantly above the background signal level (e.g., 5.0e6)

Note: Using a very high threshold will also disable the primary/secondary feature in the advanced sMRM window.