Because we detect 127N and 127C channels in each MS2 spectra we always have an indication of how much carrier channel isotopic impurity has leaked into 127C channel and we always have 127N channel as our internal "true empty" channel to detect the noise level of each mass spectrometry run. If 127N and 127C are not of interest to monitor carrier channel leakage and have an empty channel data for true noise estimation, then all MS2 spectra can be started from 127.5 m/z to include only single cell channels. Currently all ions including carrier channel TMT (for SCREEN this is 126 channel) are transported into the orbitrap for detection, in some cases, since majority of ions are TMT126 ions, that could lead to fast filling of the orbitrap cell, depending upon the AGC (automatic gain control) settings that was set for the analysis.