Resolution Enhanced Mode (REM)

Overview

Resolution Enhancement Mode (REM) provides an approximate 100 k increase in resolution by increasing ion flight path length from 47 m to 93 m. This is achieved by a timed deflection pulse on the first periodic lens, the start time and duration of which define the m/z range to undergo two passes of the analyzer.

For further details, see Understanding the modes of operation on the SELECT SERIES™ MRT

Important notes when operating in REM mode

• In REM, highest mass accuracy is achieved when the m/z of interest is within the m/z range of the calibration profile.
• For optimum mass accuracy, the user is advised to allow more than five minutes of settle time in REM before acquiring data. The same time duration should be applied to the initial data acquisition during manual calibration.
• When acquiring a mixed mode sample list (MRT and REM), optimum mass accuracy will be achieved if a blank injection(s) is performed after switching modes to allow for greater than five minutes settle time.
• In REM, space charge effects within the analyzer can lead to decreases in m/z resolution and may be observed for peak areas greater than 2 x 10⁶ at 1 Hz. The effect may be more prominent for multiply charged ions.

For more information, see the MRT software release notes 721028084.