Higher-Energy Collisional Dissociation in the Existing High Pressure Multipole Region of a Stand-Alone Ion Trap Mass Spectrometer

A method for higher-energy collisional dissociation (HCD) in an ion trap mass spectrometer (ITMS) has been developed. Precursor ions are selected in the ITMS and passed to the high pressure RF-only multipole (MP00) for dissociation. Fragment ions are then transferred back to the ITMS for mass analysis. Conventionally, collision induced dissociation in an ITMS is performed by resonantly exciting precursor ions (rCID) in the presence of buffer gas. This method is robust and informative. However, low-mass fragment ions are not captured and generally only primary fragmentation pathways of lower energy are observed. By performing HCD in MP00, both of these limitations are overcome, opening the way for applications such as peptide quantification by isotopic labeling strategies.