What is the Difference Between an EMC and an EMS Scan on a QTRAP® System?

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

Answer

The EMS and EMC scans are two different scan types that can be run on a QTRAP® system, making use of the linear ion trap (LIT) functionality. The EMS or enhanced mass scan is a full mass range MS scan in the LIT. The EMC or enhanced multiple charge scan is carried out in the LIT, where high charge state ions are selectively trapped and scanned.

In both scan types, ions are transmitted from the ion source though the quadruples (in RF mode only). In an EMS scan, once the ion trap is filled, the ions are scanned out axially to the detector. High CAD gas settings are used. In an EMC scan, after trapping the ions, only singly charged ions are emptied from the ion trap, leaving predominantly multiply charged ions behind. Next, the multiply charged ions are scanned out axially to the detector. Source and gas parameters are set the same as an EMS scan. The EMC scan type can be used for intact proteins.